51 Wetland Birds of Colorado: ID, Habitat, & Sounds Guide

Discover the wetland birds of Colorado with this identification guide featuring 51 species plates. To simplify bird ID across the Sooner state, we categorize resident and migrant birds by size—from massive pelicans to secretive rails. Learn to recognize key traits, habitats, and behavior within Colorado’s vast marshes and swamps.

How to use this Guide

Click on any of the four size groups below (Crane, Stork, Egret, and Gallinule) to explore the species included in the category. You can also use the Table of Contents below this section to browse the entire guide.

While weight offers a useful starting point, appearances can be deceiving—plumage, body shape, and leg length often make a bird look larger or smaller than its true size.

Colorado Wetlands

Colorado contains approximately 400,000 to 500,000 hectares (1 million to 1.25 million acres) of wetlands, which represent about 1.5% to 3% of the state’s total area. 

• Disproportionate Biodiversity: While wetlands and riparian areas cover less than 3% of the Colorado landscape, they support a disproportionate share of its biodiversity, including more than 90% of the state’s bird species during some portion of their life cycles.
• Summer Breeding Diversity: During the summer months, Colorado’s wetlands provide critical breeding habitat for at least 82 different bird species, including 16 types of ducks, 8 types of wading birds, and 32 species of songbirds.
• Historical Decline: It is estimated that Colorado has lost approximately 50% of its original natural wetlands over the last two centuries due to land-development pressures, though some new ancillary wetlands have been created through irrigation and land-use changes. 

Wetlands constitute less than 5% of the land area of the contiguous United States.

More about wetlands: Understanding Wetlands: An Overview for State Bird Guides

Birds of Colorado’s Marshes, Swamps, and Riparian Wetlands

This guide highlights the 51 bird species most closely tied to Colorado’s water systems. It features classic wading species—herons, egrets, and ibises—along with other wetland regulars like loons, grebes, coots, rails, and snipes.

While these species are the focus of this guide, they are rarely the only birds you’ll find in the marsh. For a broader overview of the species commonly seen in open water, shallows, and grassy edges, explore our Guide to the Ducks, Geese, and Swans of Colorado.

The breakdown of wetland birds by group is as follows:

• Herons, Egrets, and Bitterns: This group contains 11 species, representing approximately 21.6% of the total.
• Gulls & Terns: This group contains 7 species, representing approximately 13.7% of the total.
• Grebes: This group contains 6 species, representing approximately 11.8% of the total.
• Rails, Coots, Gallinules, and Swamphens: This group contains 6 species, representing approximately 11.8% of the total.
• Ibises: This group contains 4 species, representing approximately 7.8% of the total.
• Loons: This group contains 3 species, representing approximately 5.9% of the total.
• Raptors (Hawks, Kites, Eagles, Osprey): This group contains 3 species, representing approximately 5.9% of the total.
• Blackbirds: This group contains 3 species, representing approximately 5.9% of the total.
• Avocets and Stilts: This group contains 2 species, representing approximately 3.9% of the total.
• Pelicans, Cormorants, and Anhinga: This group contains 2 species, representing approximately 3.9% of the total.
• Snipe & Woodcock: This group contains 2 species, representing approximately 3.9% of the total.
• Single-Entry Species: The Sandhill Crane, Belted Kingfisher, and Killdeer are represented by a single entry each, collectively making up the remaining 5.9% of the list.

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Very Large Wetland Birds of Colorado (>10 lb)

This category includes the true giants of Colorado’s wetlands. Though few in number, these species command attention with their size, broad wingspans, and body mass. Individuals in this group range from approximately 11 to over 16 pounds, making them the heaviest regularly occurring wetland birds in the state. Their size, slow wingbeats, and visual presence distinguish them clearly from all other waterbirds.

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American White Pelican

Silent

Identification: Adult: Snowy white with black flight feathers visible in flight. Yellow-orange bill and legs; breeding adults show a yellow chest patch and grow a bill horn. Immature: Mostly white with dusky head, neck, and back.
Habitat: The American White Pelican (Pelecanus erythrorhynchos) forages in shallow inland marshes, lake and river edges, estuaries, sloughs, and inlets.
Status and Movements: The American White Pelican is a summer resident and transient in Colorado. These majestic birds arrive in spring, nesting on large reservoirs, and depart by early fall, offering impressive sights on open water.
Behavior: Forages by dipping bill at the water’s surface to scoop fish; also upends like dabbling ducks. Known for cooperative foraging, driving fish toward shore. Highly gregarious.
Diet: Primarily small fish, but also salamanders, tadpoles, crayfish, and game fish.
Nest: A shallow depression on the ground, sometimes lined with vegetation. Nests in colonies.
Breeding: Season: April-late August | Clutch: 2 chalky white eggs | Incubation: ~30 days | Nestling period: 63–70 days.
Lifespan: At least 23 years, 6 months.
How many are there? Global population estimated at ~450,000.
Conservation Status: Low conservation concern.

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Sandhill Crane

Identification: Adult: Slate gray with rusty wash, pale cheek, red crown, black legs. Juvenile: Gray and rusty brown, lacking pale cheek and red crown.
Habitat: The Sandhill Crane (Antigone canadensis) forages in open wetlands, prairies, bogs, lakes, croplands.
Status and Movements: The Sandhill Crane is a prominent migrant and transient through Colorado, with some localized breeding. Large flocks pass through in early spring and again in fall, offering spectacular viewing opportunities across the plains.
Behavior: Forages for food by gleaning/probing. Social. Pairs perform elaborate dances.
Diet: Sandhill cranes feed on invertebrates, small vertebrates, seeds, berries, tubers.
Nest: Cup-shaped structure of dominant vegetation, 30–40 in across, on the ground.
Breeding: Season: Jan to May. Breeding age: 2–7 years | Clutch: 1–3 pale brownish yellow/gray markings eggs | Broods: 1 | Incubation: 29–32 days | Offspring dependency: 9–10 months.
Lifespan: At least 37 years, 3 months.
How many are there? The global population of Sandhill Cranes is estimated to be between 650,000 and over 800,000 individuals.
Conservation Status: Low concern.

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Common Loon

Identification: Breeding: black head, spotted back, white breast. Nonbreeding: gray back/head, white throat. Juvenile: like nonbreeding with scalloping. Large, rounded head, dagger-like bill.
Habitat: The Common Loon (Gavia immer) favors clear freshwater lakes, ponds, islands, seacoasts, reservoirs, estuaries, rivers.
Status and Movements: The Common Loon is a transient and winter visitor to Colorado. Look for this distinctive diver on larger lakes during spring and fall migration, with some individuals remaining through winter on unfrozen waters.
Behavior: Stealthy divers, catch fish underwater. Monogamous pairs; vocal nocturnal choruses. Males yodel for territory.
Diet: Common loons feed on fish, perch, sunfish, croaker, silversides, crustaceans, snails, leeches, aquatic insect larvae.
Nest: Mound of dead sedges and grasses on protected lakeshores or islands near water.
Breeding: Season: May-Oct | Clutch: 1-2 brown, with dark splotches eggs | Broods: 1 | Incubation: 26-29 days | Nestling: 1-2 days.
Lifespan: At least 29 years, 10 months.
How many are there: There are ~1.2 million Common Loons globally.
Conservation Status: Low Concern.

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Large-Wetland-Birds of Colorado (5-10 lb)

This category includes four species weighing between approximately 5 and 10 pounds. Members of this group are substantial in size and often appear even larger due to elongated legs and tall, upright posture. Their height and broad wingspans contribute to a strong visual presence in wetland habitats, placing them clearly above medium-sized species but below the heaviest wetland birds in the state.

Bald Eagle

Identification: Striking white head and tail contrasting with a dark brown body and wings, plus yellow legs and bill. Immatures are dark with mottled brown-and-white, and take about five years to acquire full adult plumage.
Habitat: The Bald Eagle (Haliaeetus leucocephalus) is found in forests near large bodies of water with tall mature trees for nesting. In winter, they use dry open uplands as well.
Status and Movements: The Bald Eagle is a year-round resident and common winter visitor in Colorado. Numbers swell significantly from November to March as northern birds arrive, often seen near open water and along major rivers.
Behavior: Powerful fliers that hunt, steal prey from other animals, scavenge carrion, and even feed on garbage.
Diet: Primarily fish, but also birds, reptiles, amphibians, crabs, rabbits, and muskrats.
Nest: Bald Eagles have the largest nests of any North American bird. Nests are placed in tall trees, cliffs, or occasionally on the ground.
Breeding: Season: December-mid-May (South) | Clutch: 1–3 dull white, usually unmarked eggs | Broods: 1 | Incubation: 34–36 days | Nestling period: 56–98 days.
Lifespan: At least 38 years.
How many are there? Over 316,000 individuals in the U.S. Lower 48.
Conservation Status: Low Concern.

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Great Blue Heron

Identification: Largest North American heron with long legs, S-shaped neck, and dagger-like bill. Blue-gray plumage, black eye stripe, and shaggy head. A white morph occurs in the Florida Keys.
Habitat: The Great Blue Heron (Ardea herodias) favors fresh, saltwater, brackish wetlands, ditches, and farmland.
Status and Movements: The Great Blue Heron is a widespread resident and summer breeder across Colorado. While present year-round, their numbers peak during the breeding season, often found stalking prey in shallow waters statewide.
Behavior: Hunts by standing still or stalking in shallow water. Flies with neck tucked and legs trailing. Defends feeding territories.
Diet: Fish, amphibians, reptiles, mammals, insects, and birds. Prey grabbed or impaled with bill.
Nest: Great Blue Herons build a stick platform in trees; also on ground, bushes, or man-made structures. Often in colonies.
Breeding: Season: March–August | Clutch: 2–6 pale blue eggs | Broods: 1–2 | Incubation: 27–29 days | Nestling: 49–81 days.
Lifespan: At least 24 years, 6 months.
How many are there?? About 700,000 globally.
Conservation Status: Stable, low concern.

Medium-sized Wetland Birds of Colorado (4–1 lb)

This group includes species that fall within an intermediate weight range of approximately 3.7 to 1 pound. It represents one of the most diverse and potentially confusing size categories, as body shape and structure vary considerably within the same weight bracket. Some species appear large and long-limbed, while others are compact and low-profile, creating notable contrasts despite overlapping weights.

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Pacific Loon

Identification: Breeding: gray head, black back with white lines, black throat. Nonbreeding: gray-brown above, white below. Juveniles: pale-edged feathers. Sturdy, pointed bill.
Habitat: Tundra, taiga lakes, coastal ocean, bays, estuaries, reservoirs.
Status and Movements: The Pacific Loon is a rare transient in Colorado, primarily observed during fall migration from late October through November. Spring sightings are less common, typically occurring in late April to early May.
Behavior: Forages by diving with slight forward leap. Highly territorial during breeding; social during migration.
Diet: Small fish, snails, mollusks, insect larvae, zooplankton, squid, seeds.
Nest: Mud and vegetation mound on islands or shorelines; occasionally floating.
Breeding: Season: Jun-mid Oct | Clutch: 1-2 buff, brown, or olive-green eggs | Broods: 1 | Incubation: 23-28 days | Nestling: 1-2 days.
Lifespan: Up to 20 years.
How many are there: There are ~840,000 Pacific Loons globally.
Conservation Status: Low Concern.

Double-crested Cormorant

Identification: Adult: Brown-black plumage, yellow-orange facial skin. Breeding adults show double crests (black/white). Immatures browner, with pale neck/breast.
Habitat: The Double-crested Cormorant (Nannopterum auritum) favor freshwater and saltwater habitats, coasts, large inland lakes.
Status and Movements: The Double-crested Cormorant is a common summer resident and transient in Colorado. These fish-eating birds arrive in spring to breed on reservoirs and depart by early fall, often seen drying wings on snags.
Behavior: Dives to catch small fish, spreads wings to dry. Flies in V-shaped flocks, nests colonially.
Diet: Double-crested Cormorants feed on mainly small fish.
Nest: Bulky stick nest, often in tree colonies.
Breeding: Season: Varies in every region | Clutch: 1-6 unmarked pale blue eggs | Broods: 1-2 | Incubation: 25-28 days | Nestling: 21-28 days.
Lifespan: At least 23 years, 8 months.
How many are there? Abundant.
Conservation Status: Low concern.

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Osprey

Identification: Dark brown upperparts, white underparts. White head marked with a bold brown eye stripe. Juveniles have white spots on the back and buff-tinted breast shading.
Habitat: Ospreys (Pandion haliaetus) inhabit open waters with abundant fish; plus elevated nesting sites.
Status and Movements: The Osprey is a summer resident and transient in Colorado. This skilled fish-hawk arrives in spring to nest near water bodies, departing south by early fall after raising its young, a true fishing marvel.
Behavior: Hunts live fish by hovering and diving feet-first. Mostly solitary; males perform aerial “sky-dance” displays.
Diet: Ospreys feed almost exclusively live fish (99%), occasionally fish remains, birds, snakes, voles, squirrels.
Nest: Large, untidy stick platforms, often on poles, snags, dead trees, or artificial platforms.
Breeding: Season: mid April-early September | Breeds spring–fall | Clutch: 1–4 cream spotted with reddish eggs | Broods: 1 | Incubation: 36–42 days | Nestling period: 50–55 days.
Lifespan: At least 25 years, 2 months.
How many are there? ~1.2 million global breeding population.
Conservation Status: Low Concern.

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Red-throated Loon

Identification: Breeding: gray neck, rusty throat patch, black-and-white neck stripes. Nonbreeding: blackish above, white face/underparts. Juvenile: grayish brown above, pale below. Slender with bill tipped upward.
Habitat: The Red-throated Loon (Gavia stellata) favors tundra, taiga lakes, marine coasts, large lakes, bays, estuaries, sounds, shallow coastal waters.
Status and Movements: The Red-throated Loon is a very rare transient in Colorado. This species is most often noted during fall migration, typically from October to November, with extremely infrequent spring observations.
Behavior: Dives for fish; scans underwater by dipping head. Highly mobile; social during migration, forming large flocks.
Diet: Red-throated loons feed on fish, leeches, copepods, crustaceans, mollusks, squid, polychaete worms, aquatic insects.
Nest: Mounds of moss, mud, and vegetation built on shorelines or shallow water of small ponds.
Breeding: Season: May-Sep | Clutch: 1-2 brown to olive, speckled eggs | Broods: 1 | Incubation: 24-31 days | Nestling: <1 day.
Lifespan: At least 23 years and 7 months.
How many are there: Estimated global breeding population is ~260,000.
Conservation Status: Low Concern.

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Western Grebe

Identification: Crisp black-and-white, sharp neck transition. Black head, white below eye. Yellowish bill, red eyes. Juveniles have blackish or silvery down. 
Habitat: The Western Grebe (Aechmophorus occidentalis) favors freshwater lakes, marshes, reeds, rushes, ocean shores, bays, rivers, estuaries. 
Status and Movements: The Western Grebe is a summer resident and transient in Colorado. Known for its elegant courtship dances, this species arrives in spring to breed on larger lakes, departing by fall for warmer climes.
Behavior: The Western Grebe forages by deep diving. Synchronized “rushing” and “weed” ceremonies. Colonial; territorial at nest. 
Diet: Western grebes feed on fish, salamanders, crustaceans, marine worms, grasshoppers, aquatic insects, larvae. 
Nest: Floating vegetation mound anchored in emergent plants. Nests in colonies of hundreds. 
Breeding: Season: Jun-mid Aug | Clutch: 2-3 pale bluish eggs | Broods: 1 | Incubation: 24 days | Nestling: <1 day. 
Lifespan: At least 11 years. 
How many are there?: There are ~87,000 Western Grebes globally. 
Conservation Status: Least Concern.

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Clark’s Grebe

Identification: Blackish above, white below. White face surrounds red eye; black cap. Vivid orange bill; long, slender neck. Young ride on parents’ backs. 
Habitat: The Clark’s Grebe (Aechmophorus clarkii) favors marshes, freshwater lakes, emergent vegetation, saltwater coasts, sheltered bays, rivers, estuaries. 
Status and Movements: The Clark’s Grebe is a summer resident and transient in Colorado, often found alongside Western Grebes. It arrives in spring to breed on large lakes, departing for warmer climes by fall, a striking presence.
Behavior: Forages by deep diving far from shore. Famous “rushing” and “weed” courtship ceremonies. Colonial and territorial.
Diet: Clark’s grebes feed on fish, salamanders, crustaceans, marine worms, grasshoppers, aquatic insects, larvae. 
Nest: Floating vegetation mound anchored in emergent plants. Nests in colonies of hundreds on large lakes. 
Breeding: Season: Jun-mid Aug | Clutch: 2-3 pale bluish eggs | Broods: 1 | Incubation: 24 days | Nestling: <1 day. Breeding information not well known, but likely similar to that of the Western Grebe.
Lifespan: Not known. 
How many are there?: There are ~11,000 Clark’s Grebes globally. 
Conservation Status: Low Concern.

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American Herring Gull

Identification: Breeding: White head, light gray back, black wingtips with white spots, yellow bill with red spot, pink legs. Nonbreeding: Brown streaking on head and neck. Juvenile: Brown-mottled overall, dark bill, pinkish-brown legs; gradually pales over four years.
Habitat: The American Herring Gull (Larus smithsonianus) favors coasts, lakes, rivers, estuaries, mudflats, fields, landfills, parking lots.
Status and Movements: The American Herring Gull is a common winter visitor and transient in Colorado. These large gulls arrive in late fall, frequenting reservoirs and landfills throughout the winter months, departing by spring.
Behavior: The American Herring Gull forages by scavenging or stealing. Social, found in large flocks and colonies.
Diet: Fish, crustaceans, mollusks, insects, eggs, refuse, carrion.
Nest: Shallow scrape on ground lined with grass, seaweed, or feathers. Breeds in colonies.
Breeding: Breeding Months: Late April-August | Clutch: 1-3 olive, buff, or bluish eggs | Broods: 1 | Incubation: 27-30 days | Nestling: ~5 days.
Lifespan: At least 29 years, 3 months.
How many are there?: There are ~430,000 breeding American Herring Gulls.
Conservation Status: Least Concern.

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White Ibis

Identification: Adult: All white with black wingtips, red/pink legs, face and bill. Juvenile: Brown above, white below, streaked brown neck, orange-pink legs and bill.
Habitat: The White Ibis (Eudocimus albus) inhabits shallow wetlands, swamps, mangroves, flooded pastures, lawns, and parks.
Status and Movements: The White Ibis is an accidental visitor to Colorado, far outside its typical range. Any sighting of this striking wading bird is considered extremely rare and noteworthy within the state, a true rarity.
Behavior: Forages, flies, and nests in flocks. Feeds by walking and probing muddy bottoms.
Diet: Insects, crayfish, earthworms, fish, frogs, lizards, and snails.
Nest: Messy stick platform built in trees or shrubs within colonies. Nest locations change yearly.
Breeding: Season: March-Mid-October | Clutch: 2-4 cream to blue-green with brown splotches eggs | Broods: 1-2 | Incubation: 21-23 days | Nestling: 40–60 days.
Lifespan: At least 16 years, 4 months.
How many are there? Global population is about 2.4 million.
Conservation Status: Low concern

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Black-crowned Night-Heron

Identification: Stocky heron with light-gray body, black back and crown, and all-black bill. Immatures are brown with white spots, streaks, and yellow-and-black bills.
Habitat: The Black-crowned Night-Heron (Nycticorax nycticorax) forages in freshwater, brackish, and saltwater wetlands.
Status and Movements: The Black-crowned Night-Heron is a summer resident and transient in Colorado. This nocturnal heron arrives in spring to breed in colonies, departing by fall, though some may linger through mild winters.
Behavior: Feeds at night or dusk; rests by day perched in trees.
Diet: The Black-crowned Night-Heron feeds on fish, frogs, insects, small mammals, birds, carrion, plant matter, and garbage.
Nest: Stick platform in trees, shrubs, or cattails; nests colonially.
Breeding: Season: January-August | Clutch: 3–5 greenish-blue eggs | Incubation: 24–26 days | Nestling: 29–34 days.
Lifespan: Up to 21 years, 5 months.
How many are there? About 3 million globally.
Conservation Status: Low concern.

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American Coot

Identification: Adult: Plump, chickenlike, dark gray to black, bright white bill and forehead, small red forehead patch. Juvenile/nonbreeding: Duller gray with less distinct forehead patch.
Habitat: The American Coot (Fulica americana) prefers freshwater wetlands with emergent vegetation. Also found anywhere with standing water; ponds, city parks.
Status and Movements: The American Coot is a widespread resident and abundant migrant in Colorado. Present year-round, their numbers swell significantly during migration and throughout the winter on unfrozen waters, a common sight.
Behavior: The American Coot forages by plucking plants while walking, swimming, dabbling, or diving. Highly social in winter.
Diet: Primarily aquatic plants. Also takes insects, snails, tadpoles, and salamanders.
Nest: Floating platform anchored to emergent vegetation, woven into a shallow basket over water.
Breeding: Season: May-mid-August | Clutch: 8–12 buff with dark speckles eggs | Broods: 1–2 | Incubation: 23–25 days | Chicks: Down-covered, alert, leave nest within 6 hours.
Lifespan: At least 22 years, 4 months.
How many are there? Global breeding population about 7.1 million individuals.
Conservation Status: Low conservation concern.

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Yellow-crowned Night-Heron

Identification: Medium heron with cloudy gray plumage, black head, creamy yellow crown, and white cheek patches. Immatures are brown with fine white spots and streaked underparts.
Habitat: The Yellow-crowned Night-Heron forages (Nyctanassa violacea) in coastal wetlands; also inland in swamps, and wet fields.
Status and Movements: The Yellow-crowned Night-Heron is a rare summer visitor in Colorado. It typically arrives in late spring, breeding sparingly, and departs by early fall.
Behavior: Forages day and night with a hunched, forward-leaning posture.
Diet: The Yellow-crowned Night-Heron feeds primarily on small crabs and crayfish; also fish, snakes, and small mammals.
Nest: Stick platform with shallow center, built near or over water.
Breeding: Season: March–August | Clutch: 2–6 pale bluish-green eggs | Incubation: 24–25 days | Nestling: 30–43 days.
Lifespan: At least 6 years.
How many are there? About 400,000 globally.
Conservation Status: Low concern.

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American Bittern

Identification: Medium-sized heron with compact body, short legs, and thick neck. Warm brown and buff with bold streaks.
Habitat: The American Bittern (Botaurus lentiginosus) prefers shallow freshwater marshes with dense reeds and emergent vegetation.
Status and Movements: The American Bittern is an uncommon summer resident and transient in Colorado. It arrives in spring for breeding in marshy habitats, departing by autumn.
Behavior: When alarmed, points bill upward to blend with reeds.
Diet: The American Bittern feeds on insects, crustaceans, fish, frogs, lizards, and small mammals.
Nest: Platform of reeds lined with grasses in dense marsh vegetation.
Breeding: Season: April–August | Clutch: 2–7 beige to olive eggs | Incubation: 24–28 days | Nestling: 7–14 days, chicks remain nearby for weeks.
Lifespan: At least 8 years, 4 months.
How many are there? About 2.5 million globally.
Conservation Status: Low concern, though declining in some regions.

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Great Egret

Identification: Large white heron with long black legs, and yellow bill. Smaller than Great Blue Heron, larger than Snowy Egret. Breeding adults grow long back plumes.
Habitat: The Great Egret (Ardea alba) inhabits freshwater, brackish, and coastal wetlands.
Status and Movements: The Great Egret is an uncommon summer visitor and transient in Colorado. It appears from spring through fall, often seen foraging in wetlands and along rivers.
Behavior: Hunts by standing still in shallow water, striking quickly at prey.
Diet: Great Egrets feed on primarily fish; also amphibians, reptiles, birds, mammals, and invertebrates.
Nest: Large stick platform in trees or shrubs, usually in colonies.
Breeding: Season: March–July | Clutch: 1–6 pale greenish-blue eggs | Broods: 1–2 | Incubation: 23–27 days | Nestling: 21–25 days.
Lifespan: Up to 22 years, 10 months.
How many are there? About 9.5 million in North America.
Conservation Status: Low concern; populations increasing.

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Red-shouldered Hawk

Identification: Adult: Barred reddish-peach underparts, strongly banded tail, checkered wings, pale wing crescents near tips. Immature: Brown above, white below streaked with brown, pale wing crescents.
Habitat: The Red-shouldered Hawk (Buteo lineatus) inhabits tall woods near water, including swamps, riparian forests, and suburban parks.
Status and Movements: The Red-shouldered Hawk is a rare transient and winter visitor in Colorado. Occasional sightings occur from late fall through early spring, typically near wooded waterways.
Behavior: Hunts from perches with swift descents. Soars and glides frequently. Males perform a “sky dance” display during courtship.
Diet: Feeds on small mammals, lizards, snakes, amphibians, voles, chipmunks, and birds.
Nest: Large stick nests (~2 ft diameter), placed in tree crotches near water. Often reused in subsequent years.
Breeding: Season: Late March-July | Clutch: 2–5 dull white to bluish, brown-blotched eggs | Broods: 1 | Incubation: 32–40 days | Nestling period: 42–49 days.
Lifespan: At least 25 years, 10 months.
How many are there? Global breeding population about 1.9 million.
Conservation Status: Low conservation concern.

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Caspian Tern

Identification: Largest tern species. White overall. Breeding adults have a black crown and a coral-red bill. In winter and juveniles, the crown is partially black with grayish speckling.
Habitat: Caspian Terns (Hydroprogne caspia) are found along ocean coasts, barrier islands, interior lakes and rivers.
Status and Movements: The Caspian Tern is an uncommon transient in Colorado. This large tern passes through in spring and fall, often pausing at large reservoirs and lakes during migration.
Behavior: Caspian Terns fly slowly before plunging for fish. Roosts and rests in flocks.
Diet: Primarily fish; also crayfish, large insects, and occasionally scavenged invertebrates.
Nest: A shallow scrape in open areas lined with dried vegetation and ringed with pebbles, or other debris.
Breeding: Season: mid-May-late August | Clutch: 1-3 buff with dark spots eggs | Broods: 1 | Eggs: | Incubation: 25–28 days | Nestling: 1–2 days.
Lifespan: At least 32 years, 1 month.
How many are there? ~530,000 global breeders.
Conservation Status: Low Concern.

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White-faced Ibis

Identification: Adult: glossy maroon, metallic green/bronze wings. Pink legs, white mask. Juvenile/non
Breeding: matte brown, no white facial outline, duller legs.
Habitat: The White-faced (Plegadis chihi) favors shallow wetlands, marshes. Wet agricultural fields.
Status and Movements: The White-faced Ibis is a common summer resident in Colorado. Arriving in spring, it breeds in wetlands and departs by early fall, often in large flocks.
Behavior: White-faced Ibises forage by probing in water/mud or picking surface prey. Usually in flocks.
Diet: Earthworms, crayfish, spiders, snails, leeches and insects.
Nest: Flat platform of twigs built in emergent vegetation or shrubs.
Breeding: Season: Mid-May through late July | Clutch: 3-5 bluish green to turquoise eggs | Broods: 1 | Incubation: 17-21 days.
Lifespan: At least 12 years, 3 months.
How many are there? Globally approx. 7.2 million. U.S./Canada
Breeding: 1.3 million.
Conservation Status: Low conservation concern.

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Glossy Ibis

Identification: Deep maroon body with metallic green, bronze, and violet wing coverts. It appears black in the distance.
Habitat: The Glossy Ibis (Plegadis falcinellus) uses freshwater, brackish, and saltwater marshes and rice fields.
Status and Movements: The Glossy Ibis is a very rare transient in Colorado. This species is an infrequent visitor, with scattered sightings primarily during spring or fall migration periods.
Behavior: Feeds and nests in flocks. Forages by probing wet substrates or gleaning.
Diet: Glossy Ibises feed on aquatic invertebrates, crabs, fish, amphibians, grain, crops.
Nest: Bulky platform of sticks/reeds, on ground or in trees up to 12 ft high, in colonies.
Breeding: Season: April-June | Clutch: 3–4 eggs | Broods: 1 | Incubation: 20–22 days | Nestling: 8–9 days.
Lifespan: At least 21 years.
How many are there? In North America: 13,000–15,000 individuals.
Conservation Status: Low concern.

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Ring-billed Gull

Identification: Breeding: White head, yellow bill with black ring, yellow legs, light gray mantle, black wingtips. Nonbreeding: Streaked brown on head and neck. Juvenile: Brown-mottled overall, pinkish legs, black-tipped pink bill; becomes gray-backed with distinct tail band by second winter.
Habitat:The Ring-billed Gull (Larus delawarensis) is found in lakes, rivers, coasts, mudflats, docks, landfills, parking lots, fields.
Status and Movements: The Ring-billed Gull is a common resident and abundant migrant in Colorado. Present year-round, its numbers swell significantly during spring and fall migrations across the state.
Behavior: The Ring-billed Gull forages by scavenging or dipping. Highly social, nests in large colonies.
Diet: Fish, insects, earthworms, grain, rodents, refuse, carrion.
Nest: Scrape on ground lined with grass, twigs, or lichens. Breeds in large colonies.
Breeding: Breeding Months: late April – mid-August | Clutch: 2-4 olive gray with dark brown spots eggs | Broods: 1 | Incubation: 21-28 days | Nestling: ~5 days.
Lifespan: At least 27 years, 6 months.
How many are there?: There are ~2.5 million Ring-billed Gulls.
Conservation Status: Least Concern.

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Pied-billed Grebe

Identification: Small, chunky brown waterbird. Adults have a dark crown and nape, and a whitish bill with a black band in breeding season (yellow-brown outside breeding). Juveniles show distinctive striped faces.
Habitat: The Pied-billed Grebe (Podilymbus podiceps) occupies ponds, marshes, lakes, sluggish rivers, and areas with emergent vegetation or open water.
Status and Movements: The Pied-billed Grebe is a common summer resident and migrant in Colorado. It breeds in wetlands, arriving in spring and departing by late fall, though some may overwinter.
Behavior: Forages by diving to pursue prey. Typically solitary but may form small winter flocks.
Diet: Pied-billed Grebes feed on crayfish, shrimps, fish, frogs, tadpoles, and salamanders.
Nest: Floating open-bowl nest built anchored among emergent plants.
Breeding: Season: February-November | Clutch: 2–10 bluish white, unmarked eggs | Broods: 1–2 | Incubation: 23–27 days | Chicks: Leave the nest within 1 day.
Lifespan: At least 4 years, 7 months.
How many are there? Global breeding population about 3.1 million.
Conservation Status: Low conservation concern.

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Horned Grebe

Identification: Breeding: Dark gray back, cinnamon neck and sides, yellow head-tufts, black head. Nonbreeding: Grayish above, white below, black cap, white cheek. 
Habitat: The Horned Grebe (Podiceps auritus) favors freshwater ponds, lakes, rivers, bays, oceans, marshes, emergent vegetation. 
Status and Movements: The Horned Grebe is an uncommon winter visitor and transient in Colorado. It arrives in late fall, frequenting open waters, and departs by early spring as ice melts.
Behavior: Forages by surface diving. Highly territorial when nesting; forms small flocks during winter and migration. 
Diet: Horned grebes feed on fish, crustaceans, insects, larvae, salamanders, frogs, tadpoles, leeches, marine worms. 
Nest: Floating mass of aquatic vegetation anchored to plants or bottom near shoreline. 
Breeding: Season: Mid May-September | Clutch: 3-8 White, brownish, or bluish-green eggs | Broods: 1 | Incubation: 23-24 days | Nestling: <1 day. 
Lifespan: At least 5 years, 11 months. 
How many are there?: There are ~620,000 Horned Grebes globally. 
Conservation Status: Tipping Point Yellow Alert, due to significant long-term population declines.

Small Wetland Birds of Colorado (< 1 lb)

This group includes the lightest wetland species in the state, ranging from just under one pound to only a few ounces. Despite their small size, they occupy a wide variety of wetland habitats and can vary noticeably in structure and proportions. Several members of this category are notably secretive, often detected by voice rather than sight as they move quietly through dense marsh vegetation.

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Snowy Egret

Identification: All-white heron with black bill, black legs, and yellow feet. Immatures have duller greenish legs. Breeding adults grow filmy curving plumes.
Habitat: The Snowy Egret (Egretta thula) forages in fresh, salt, and brackish water wetlands.
Status and Movements: The Snowy Egret is a common summer resident and transient in Colorado. It arrives in spring to breed in wetlands, departing by early fall.
Behavior: Hunts in shallow water, spearing or chasing prey; uses yellow feet to stir or herd fish before striking.
Diet: Snowy Egrets feed on small fish, frogs, shrimp, and insects.
Nest: Shallow twig platform, usually over water.
Breeding: Season: March–July | Clutch: 2–6 pale greenish-blue eggs | Incubation: 24–25 days | Nestling: 20–24 days.
Lifespan: At least 17 years, 7 months.
How many are there? About 2.1 million globally.
Conservation Status: Low concern.

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Tricolored Heron

Identification: Slim, medium-sized heron with blue-gray and lavender upperparts, white belly, and dagger-like bill. Breeding adults show pale plumes; juveniles have rusty neck and feather edges.
Habitat: The Tricolored Heron (Egretta tricolor) forages salt, fresh, and brackish water wetlands, and ditches.
Status and Movements: The Tricolored Heron is a rare transient in Colorado. Infrequent sightings occur primarily during spring and fall migration, often near larger bodies of water.
Behavior: Hunts by stalking, or chasing; often spins with sudden stops and wing flaps.
Diet: Mainly small fish; also other small vertebrates.
Nest: Tricolored Herons build a bulky stick platform in trees or shrubs; often in colonies.
Breeding: Season: May–July | Clutch: 3–5 pale greenish-blue eggs | Broods: 1 | Incubation: 21–24 days | Nestling: 17–21 days.
Lifespan: At least 17 years, 8 months.
How many are there? About 194,000 breeding in the U.S.
Conservation Status: Low concern.

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Eared Grebe

Identification: Breeding: Black with chestnut flanks, golden plumes behind red eyes. Nonbreeding: Grayish-black, smudgy cheeks, white neck. Immatures are similar to nonbreeding adults.
Habitat: The Eared (Black-necked) Grebe (Podiceps nigricollis) favors shallow lakes, ponds, wetlands, saline waters, salt ponds, ocean coastlines. 
Status and Movements: The Eared Grebe is a common summer resident and migrant in Colorado. It breeds on prairie lakes, arriving in spring and departing by late fall, with some overwintering.
Behavior: Forages by diving or surface pecking. Highly social, breeds in colonies and migrates in massive flocks. 
Diet: Eared Grebes feed on brine shrimp, brine flies, aquatic invertebrates, small fish, mollusks, amphibians. 
Nest: Floating platform of aquatic plants attached to emergent vegetation. Breeds in colonies. 
Breeding: Season: May-Aug | Clutch: 1-8 whitish eggs | Broods: 1 | Incubation: 20-23 days | Nestling: <1 day. 
Lifespan: At least 8 years, 7 months. 
How many are there?: There are ~2.7 million Eared Grebes globally. 
Conservation Status: Low Concern.

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Cattle Egret

Identification: Stocky heron with short, thick neck. Adults are white with buff plumes in breeding season; bill turns bright red before pairing. Juveniles lack plumes and have black bills.
Habitat: The (Western) Cattle Egret (Bubulcus ibis)Wet grasslands, pastures, farmlands; favors drier open areas more than other herons.
Status and Movements: The Cattle Egret is an uncommon summer visitor and transient in Colorado. It arrives in spring, often associated with livestock, and departs by early fall.
Behavior: Walks with a distinctive head-pumping strut. It often follows cattle.
Diet: Cattle Egrets feed on mainly insects and other invertebrates.
Nest: Stick platform in trees, or marsh vegetation; nests colonially with other wading birds.
Breeding: Season: March–June | Clutch: 3–4 pale bluish-white eggs | Broods: 1 | Incubation: 23 days | Nestling: 30 days.
Lifespan: Up to 15 years.
How many are there? 3.8–6.7 million globally.
Conservation Status: Least Concern.

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Little Blue Heron

Identification: Adults are dark blue-gray with purple-maroon head and neck, greenish legs, and pale gray-and-black bill. Juveniles are all white; immatures are patchy white and blue.
Habitat: The Little Blue Heron (Egretta caerulea) forages in most types of wetlands and flooded fields.
Status and Movements: The Little Blue Heron is a rare transient in Colorado. This species is an infrequent visitor, with scattered records occurring mainly during spring and fall migration.
Behavior: Stand-and-wait predator, also moves slowly searching for prey.
Diet: Small fish, frogs, shrimp, insects, and other invertebrates.
Nest: The Little Blue Heron builds a porous twig platform in shrubs or small trees over water; often in mixed colonies.
Breeding: Season: March–October | Clutch: 3–4 pale bluish-green eggs | Incubation: 22–23 days | Nestling: 35–49 days.
Lifespan: Up to 13 years, 11 months.
How many are there? About 1.1 million globally.
Conservation Status: Low concern, though populations have declined.

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American Avocet

Identification: Striking black-and-white body, long upturned bill, and bluish-gray legs. In summer, the head and neck are rusty; in winter, they turn grayish-white.
Habitat: The American Avocet (Recurvirostra americana) forages in shallow freshwater and saltwater wetlands, rice fields, and flooded pastures.
Status and Movements: The American Avocet is a common summer resident in Colorado. Arriving in spring, it breeds in shallow wetlands and alkali flats, departing by early fall.
Behavior: Forages by sweeping its bill side to side, pecking, or plunging. Often associated with other shorebirds in flocks.
Diet: American Avocets feed on aquatic invertebrates, plus small fish and seeds.
Nest: A shallow ground scrape, sometimes unlined, located on islands or dikes, with little or no vegetation.
Breeding: Season: late April-early August | Clutch: 3–4 greenish brown with dark spots eggs | Broods: 1 | Incubation: 18–30 days | Nestling: able to walk within 24 hours.
Lifespan: At least 15 years.
How many are there? Global breeding population ~450,000.
Conservation Status: Low Concern.

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Common Gallinule

Identification: Charcoal gray with a distinct white side stripe. Adults feature a bright red forehead shield and red bill tipped in yellow. Immatures are similar but lack the red shield and bill coloration.
Habitat: The Common Gallinule (Gallinula galeata) inhabits freshwater and brackish wetlands. Also found in ditches, rice fields, sewage, and stormwater ponds.
Status and Movements: The Common Gallinule is a rare summer resident and transient in Colorado, typically observed from late spring through early fall in marshy habitats.
Behavior: Swims, walks on floating vegetation with a crouched posture, often flicking its tail. Highly territorial during breeding.
Diet: Aquatic vegetation and seeds, plus snails and insects.
Nest: A broad bowl, typically 10–12 inches wide, placed on thick aquatic plant mats.
Breeding: Season: April-August | Clutch: 3–15 light gray with darker specks/spots eggs | Broods: 1–2 | Incubation: 19–22 days | Chicks: leave the nest within 1 day.
Lifespan: At least 9 years, 10 months.
How many are there? Apparently declining.
Conservation Status: Low Concern.

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Franklin’s Gull

Identification: Breeding: Black hood, thick white eye arcs, dark gray mantle, white-tipped black wingtips, pinkish-white breast. Nonbreeding: White face with dark half-hood covering back of head. Juvenile: Brownish-gray back, partial black hood, dark ear patch, black tail band.
Habitatr: Franklin’s Gull (Leucophaeus pipixcan) favors prairie marshes, flooded fields, agricultural lands, coastal estuaries, bays.
Status and Movements: Franklin’s Gulls are a common spring and fall transient in Colorado, with some individuals remaining as uncommon summer residents. Look for them during migration.
Behavior: The Franklin’s Gull forages by aerial hawking or walking. Highly social, breeds in massive colonies.
Diet: Insects, earthworms, crustaceans, small fish, snails, seeds.
Nest: Floating platform of aquatic vegetation anchored to emergent plants. Breeds in dense colonies.
Breeding: Breeding Months: Late April-July | Clutch: 2-3 Olive, dark-spotted eggs | Broods: 1 | Incubation: 23-26 days | Nestling: ~5 days.
Lifespan: At least 9 years, 4 months.
How many are there?: There are ~1 million to 1.5 million Franklin’s Gulls globally.
Conservation Status: Least Concern.

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Bonaparte’s Gull

Identification: Breeding: Black hood, white eye-arcs, red legs, white outer-wing wedges. Nonbreeding: White head, prominent black ear spot, pinkish legs. Juvenile: Brown-scaled upperparts, black “M” pattern across wings, pinkish legs, dark tail band.
Habitat: The Bonaparte’s Gull (Chroicocephalus philadelphia) prefers boreal lakes, rivers, coastal bays, estuaries, mudflats, open ocean, sewage lagoons.
Status and Movements: Bonaparte’s Gull is a common spring and fall transient in Colorado. This small gull passes through rapidly, often seen over larger bodies of water during migration periods.
Behavior: The Bonaparte’s Gull forages by surface-picking or plunging. Highly social, often found in large flocks.
Diet: Insects, small fish, crustaceans, marine worms, snails.
Nest: Small platform of sticks and moss built in coniferous trees. Nests solitarily or in loose groups.
Breeding: Breeding Months: Late May-July | Clutch: 2-4 buffy-green with dark blotcher eggs | Broods: 1 | Incubation: 22-25 days | Nestling: ~6-7 days.
Lifespan: At least 18 years.
How many are there?: There are ~475,000 to 700,000 Bonaparte’s Gulls globally.
Conservation Status: Least Concern.

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Green Heron

Identification: Small heron with velvet-green back, rich chestnut body, and dark cap. Juveniles are browner with pale neck streaks and wing spots.
Habitat: The Green Heron (Butorides virescens) forages in most types of wetlands and ditches.
Status and Movements: The Green Heron is an uncommon summer resident in Colorado, arriving in late spring and departing by early fall. It favors dense vegetation along slow-moving water.
Behavior: Hunts by standing still or walking slowly in shallow water; strikes quickly when prey approaches.
Diet: Green Herons feed on small fish, shrimp, frogs, and insects.
Nest: Simple stick platform, in trees or shrubs. It is a solitary breeder.
Breeding: Season: February–July | Clutch: 3–5 pale green to bluish eggs | Broods: 1–2 | Incubation: 19–21 days | Nestling: 16–17 days.
Lifespan: Up to 8 years, 11 months.
How many are there? About 1.2 million globally.
Conservation Status: Bird in steep decline (~51%).

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American Woodcock

Identification: Plump bird, very long straight bill, short tail. Cryptic plumage. Hatchlings covered in thick down.
Habitat: The American Woodcock (Scolopax minor) if founs in forests openings and clearings, young shrubby deciduous forests, old fields, wet meadows.
Status and Movements: The American Woodcock is a rare transient and very rare summer resident in Colorado. Its cryptic plumage makes it challenging to spot in damp woodlands during spring and fall.
Behavior: Forages probing soil for earthworms. Often rocks body while walking. Generally solitary; sometimes small clusters (2–4).
Diet: Earthworms, invertebrates, snails, millipedes, spiders, flies, beetles, ants. Plant material: sedges, pigweed.
Nest: Shallow depression on ground. Made by the female in leaf and twig litter. Usually in young upland woods.
Breeding: Breeding Months: January through May | Clutch: 1-5 grayish orange with splotches of brown eggs | Incubation: 20–22 days | Nestling: ~30 days (Independence).
Lifespan: 11 years, 4 months.
How many are there? Global population ~3.5 million individuals.
Conservation Status: Low Concern.

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Black-necked Stilt

Identification: Elegant black-and-white with long rose-pink legs, slender black bill, and a white patch around the eye. Females and juveniles show browner-black plumage in dark areas.
Habitat: The Black-necked Stilt (Himantopus mexicanus) is found in shallow wetlands, mudflats, sewage or evaporation ponds, and mangrove swamps.
Status and Movements: The Black-necked Stilt is a common summer resident in Colorado, arriving in April and departing by September. Its striking black and white plumage is distinctive in shallow wetlands.
Behavior: Forages by wading and pecking, sometimes swinging the bill through water. Loud alarm calls and group displays help deter predators.
Diet: Black-necked Stilts eat primarily aquatic invertebrates; also take small amounts of seeds and plant material.
Nest: Shallow ground scrape on islands, in vegetation, or on floating mats.
Breeding: Season: April-August | Clutch: 2–5 tawny olive, dark brown speckling eggs | Broods: 1 | Incubation: 24–29 days | Nestling: Able to run within ~2 hours.
Lifespan: At least 12 years, 5 months.
How many are there? Estimated global, 900,000 individuals.
Conservation Status: Low Concern.

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Belted Kingfisher

Identification: Stocky, large-headed bird with shaggy crest, thick bill. Blue-gray above, white below with blue breast band. Females have rusty belly bands. Juveniles show rusty spotting.
Habitat: The Belted Kingfisher (Megaceryle alcyon) forages at streams, rivers, ponds, lakes, estuaries, and human-made pits.
Status and Movements: The Belted Kingfisher is a common resident throughout Colorado, often seen perched over clear water. Its distinctive rattle call and diving prowess are observable year-round.
Behavior: Forages alone from a perch or by hovering, diving for prey. Territorial and solitary. Loud rattling calls.
Diet: Fish, crayfish, insects, amphibians, young birds, small mammals, berries.
Nest: Burrow in earthen bank near water, 3–6 ft deep, sloping upward to unlined chamber.
Breeding: Season: Mid-March-Late July | Clutch: 5–8 pure white eggs | Broods: 1–2 | Incubation: 22–24 days | Nestling: 27–29 days.
Lifespan: Typically 6 to 10 years.
How many are there? Global breeding population ~1.8 million.
Conservation Status: Low Concern.

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Forster’s Tern

Identification: Breeding adults are gray above, white below, with a black cap and an orange bill tipped in black. Nonbreeding adults have a thick black eye patch and a pale head. Juveniles resemble nonbreeding birds but have tan upperparts, a pale bill base, and shorter tails.
Habitat: The Forster’s Tern (Sterna forsteri) uses freshwater, brackish, and saltwater wetlands and bodies of water.
Status and Movements: Forster’s Tern is a common summer resident in Colorado, arriving in spring to breed at wetlands and departing by early fall. Look for its elegant flight over water.
Behavior: Forages mainly by plunge-diving for fish; sometimes hunts from perches. Highly social, often in flocks.
Diet: Forster’s Terns feed on small fish and insects.
Nest: A shallow scrape or rough bowl on the ground in marsh vegetation, floating mats, or atop muskrat lodges.
Breeding: Season: May-mid August | Clutch: 1–4 olive with dark spots eggs | Broods: 1 | Incubation: 23–28 days | Nestling period: 2–7 days.
Lifespan: At least 15 years, 10 months.
How many are there? ~98,000 global breeders.
Conservation Status: Low Concern.

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Great-tailed Grackle

Identification: Male iridescent black, white eyes, massive keel-shaped tail. Female dark brown, white eyes. Juveniles have dark brown eyes. Overlaps with similar Boat-tailed Grackle (above) in coastal Texas, but Boat-tails are confined to salt marshes and have brown eyes, unlike the white-eyed Great-tailed Grackle found in varied habitats.
Habitat: Marshes, lakes, lagoons, agricultural fields, feedlots, suburbs.
Status and Movements: The Great-tailed Grackle is an increasingly common resident in Colorado, particularly in urban and suburban areas. Its distinctive calls and long tail are noticeable year-round.
Behavior: Highly social, loud birds. Often form large flocks. Forages in urban settings.
Diet: Grains, fruits, insects, tadpoles, frogs, fish, small mammals.
Nest: Bulky cup woven from grasses, bark, and weeds. Lined with mud and fine grasses.
Breeding: Breeding Months: mid-March-late July | Clutch: 1-5 bright blue to bluish gray, dark brown splotches eggs | Broods: 1-2 | Incubation: 13-14 days | Nestling: 20-23 days.
Lifespan: At least 7 years, 9 months.
How many are there? Global population ~30 million individuals.
Conservation Status: Low Concern.

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Wilson’s Snipe

Identification: Pudgy bird, very long straight bill. Intricately patterned. Hatchlings tan/chestnut down, black blotches, white crown streak.
Habitat: The Wilson’s Snipe (Gallinago delicata) forages in marshes, bogs, fens, wet meadows, rivers, ponds, wet pastures, muddy pond edges, and damp fields.
Status and Movements: Wilson’s Snipe is a common transient and uncommon summer/winter resident in Colorado. This secretive shorebird favors wet meadows and marshes, often flushing unexpectedly.
Behavior: Probes wet soil methodically. Swallows prey without removing bill. Elusive. Performs winnowing courtship display.
Diet: Wilson’s snipes feed on aquatic invertebrates, insect larvae, worms, snails, crustaceans. Occasionally lizards, frogs, and fish.
Nest: Shallow scrape in moist soil. Lined with coarse and finer grasses. Hidden on ground near water.
Breeding: Breeding Months: Mid-March-late August | Clutch: 2-4 olive brown splotched dark brown eggs | Incubation: 18-20 days | Nestling: Chicks leave the nest day of hatching.
Lifespan: At least 9 years, 3 months.
How many are there? Global population ~2 million individuals.
Conservation Status: Low Concern.

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Killdeer

Identification: Brownish-tan above, white below, with two distinct black breast bands and a black-and-white patterned face. Chicks with a single black breast band.
Habitat: The Killdeer (Charadrius vociferus) forage on lawns, pastures, golf courses, athletic fields, parking lots.
Status and Movements: The Killdeer is a common summer resident and uncommon winter resident in Colorado. Its distinctive “kill-deer” call and broken-wing display are familiar sights in open areas.
Behavior: Forages by running and stopping to search the ground for food. Famous for the “broken-wing” distraction display to protect nests.
Diet: Killdeer feed on earthworms, grasshoppers, beetles, aquatic insect larvae, seeds, and frogs.
Nest: A shallow ground scrape, often decorated with rocks, shells, sticks, or debris.
Breeding: Season: March-October | Clutch: 4–6 buff with heavy blackish markings eggs | Broods: 1–3 | Incubation: 22–28 days | Nestlings: leave nest as soon as down is dry.
Lifespan: At least 10 years, 11 months.
How many are there? ~2.3 million global breeders.
Conservation Status: Low Concern.

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Least Bittern

Identification: Tiny heron; males are blackish above and buffy-brown below, females and juveniles are more uniformly brown. Juveniles appear scaly.
Habitat: The Least Bittern (Ixobrychus exilis) forages in freshwater and brackish marshes with tall cattails or reeds.
Status and Movements: The Least Bittern is a rare summer resident in Colorado, arriving in late spring. This secretive marsh bird is best located by its low “coo-coo-coo” call from dense cattails.
Behavior: Hunts by standing still perched on standing reeds. When disturbed, compresses the body, raises neck and bill, and sways with reeds for camouflage.
Diet: The Least Bittern feeds on small fish, frogs, shrimp, mice and, dragonflies.
Nest: Well-hidden platform of reeds and sticks, about 6-30 inches above water.
Breeding: Season: April–July | Clutch: 2–6 pale blue or green eggs | Broods: 1–2 | Incubation: 17–20 days | Nestling: 6–15 days.
How many are there? About 310,000 globally.
Conservation Status: Low concern.

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Virginia Rail

Identification: Small, chickenlike with bill and short, upturned tail. Rusty overall with a gray face and black-and-white barred sides. Legs and bill are reddish.
Habitat: The Virginia Rail (Rallus limicola) inhabits shallow freshwater wetlands as well as muddy bottoms, saltmarshes, and brackish wetlands.
Status and Movements: The Virginia Rail is a common summer resident and uncommon winter resident in Colorado. Its “kid-ick” call is often heard from dense marsh vegetation, though it’s rarely seen.
Behavior: Forages by probing mud for prey. Usually solitary. Notable for jerky movements and frequent tail flicking.
Diet: Virginia Rails feeds on insects, small fish, frogs, and plant material including seeds in winter.
Nest: Woven basket of wetland vegetation, placed on floating mats at or just above the water surface.
Breeding: Clutch: 4–13 white/buff with sparse irregular brown spots eggs | Broods: 1–2 | Incubation: 18–20 days | Young: Leave nest after 3–4 days.
Lifespan: Not available.
How many are there? Trends appear stable, though difficult to estimate due to secretive behavior.
Conservation Status: Low conservation concern.

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Sora

Identification: Small, chubby rail with mottled gray and brown plumage. Distinctive yellow bill, black mask and throat patch. Females are duller with less black on the face and throat; juveniles lack the mask. Short tail is often cocked upward.
Habitat: The Sora (Porzana carolina) inhabits freshwater and brackish wetlands, wet pastures, ditches, and flooded fields during migration and winter.
Status and Movements: The Sora is a common summer resident and transient in Colorado. Its distinctive “sora-sora” call is a hallmark of freshwater marshes from spring through early fall.
Diet: Soras feed on seeds and aquatic invertebrates.
Nest: Shallow basket of cattails or sedges, built on mounds or attached to stems above shallow water.
Breeding: Season: May-August | Clutch: 6–10 cream to cinnamon with irregular brown spots eggs | Broods: 1–2 | Incubation: 17–20 days | Chicks: Leave the nest within 1 day.
Lifespan: Not available.
How many are there? Stable; Considered abundant.
Conservation Status: Low conservation concern.

Yellow-headed Blackbird

Identification: Breeding: Adult male black with bright yellow head/breast, white wing patches. Female/Immature male: Dull yellow head/breast, dusky brown body, lacks wing patches. Nonbreeding: Males retain yellow, but feathers tipped with dusky; females/immatures even duller. Juvenile: Buff-colored head and throat, brownish-gray body.
Habiat: The Yellow-headed Blackbird (Xanthocephalus xanthocephalus) uses freshwater marshes, wetlands, agricultural fields, pastures, prairies.
Status and Movements: The Yellow-headed Blackbird is a common summer resident in Colorado, arriving in spring. Males with their striking yellow heads and black bodies are conspicuous in cattail marshes.
Behavior: The Yellow-headed Blackbird forages by gleaning and ground-picking. Highly social; breeds in dense, territorial colonies.
Diet: Insects, spiders, seeds, grains.
Nest: Deep, woven cup of wet vegetation lashed to standing marsh plants. Breeds in colonies.
Breeding: Breeding Months: May–July | Clutch: 2–5 Grayish-white, brown-spotted eggs | Broods: 1–2 | Incubation: 11–13 days | Nestling: 9–14 days.
Lifespan: At least 11 years, 8 months.
How many are there?: There are ~11 million Yellow-headed Blackbirds globally.
Conservation Status: Least Concern.

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Black Tern

Identification: Breeding: Jet-black head and underparts, gray wings and tail, white undertail coverts. Nonbreeding: White face and underparts, dark crown and ear patch, dark smudge on breast sides. Juvenile: Similar to nonbreeding adult but with brown scaling on back and wings.
Habitat: The Black Tern (Chlidonias niger)Freshwater marshes, lake edges, wet prairies, coastal lagoons, open ocean.
Status and Movements: The Black Tern is a common summer resident and transient in Colorado, arriving in late spring. Its graceful, buoyant flight over wetlands is a characteristic summer sight.
Behavior: The Black Tern forages by hovering and dipping. Social, breeds in loose colonies, migrates in flocks.
Diet: Insects, small fish, spiders, crustaceans, tadpoles.
Nest: Fragile, floating cup of vegetation in shallow water. Breeds in loose colonies.
Breeding: Breeding Months: Mid-May-August | Clutch: 2-4 olive, dark-spotted eggs | Broods: 1 | Incubation: 17-22 days | Nestling: 18-24 days.
Lifespan: At least 11 years, 3 months.
How many are there?: There are ~850,000 Black Terns globally.
Conservation Status: Least Concern.

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Red-winged Blackbird

Identification: Adult males are glossy black with bright scarlet-and-yellow shoulder patches. Females are streaky dark brown with a paler breast and a whitish eyebrow.
Habitat: The Black Tern (Chlidonias niger) uses freshwater or saltwater marshes and the like, agricultural fields, feedlots, wet roadsides, and even golf courses.
Status and Movements: The Red-winged Blackbird is an abundant resident throughout Colorado. Males with their vibrant red epaulets are a familiar sight and sound in wetlands and open fields year-round.
Behavior: Males sing from high perches and aggressively defend territories. Highly social, with winter roosts often numbering in the millions, mixed with other blackbirds.
Diet: Red-winged Blackbirds feed on insects in summer; seeds and grains in winter.
Nest: Females build a cup-shaped nest in marsh vegetation, shrubs, trees, or crops.
Breeding: Season: April-early August | Clutch: 2–4 pale blue-green to gray with dark markings eggs | Broods: 1–2 | Incubation: 11–13 days | Nestling: 11–14 days.
Lifespan: At least 15 years, 9 months.
How many are there? ~180 million globally.
Conservation Status: Low concern.

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Black Rail

Identification: Tiny bird with gray-black plumage speckled white, black crown, chestnut nape, and red eyes. Immatures have less white and amber to hazel eyes.
Habitat: The Black Rail (Laterallus jamaicensis) occupies shallow wetlands, riparian zones, coastal prairies, saltmarshes, and rice fields.
Status and Movements: The Black Rail is an extremely rare summer resident and transient in Colorado. This tiny, secretive rail inhabits dense marshes, making it one of the most challenging birds to observe.
Behavior: Forages by gleaning invertebrates. Males defend territories and sing.
Diet: Black Rails feed on small invertebrates, as well as seeds from bulrush and cattail.
Nest: Circular bowl of fine grasses placed on the ground at the base of tall vegetation, often with a ramp of dead plant material.
Breeding: Season: March-early September | Clutch: 4–13 creamy white with fine brown spots eggs | Broods: 1–2 | Incubation: 17–20 days | Chicks: Leave the nest within 1 day.
Lifespan: Estimated at 5–9 years.
How many are there? Eastern subspecies numbers only 355–815 breeding pairs.
Conservation Status: The eastern subspecies is listed as Threatened under the U.S. Endangered Species Act.

Foraging Strategy and Habitat use as tools to Identify Colorado Wetland Birds

Even though many birds share wetlands, they don’t all feed in the same way. Each species uses specific strategies—diving, wading, probing mud, or hunting from the air—based on its food preferences and adaptations. For birdwatchers, knowing these foraging groups helps predict where certain species are most likely to be found in a wetland, making it easier to spot and identify them.

The table below summarizes the main foraging groups of Colorado’s wetland birds, their preferred habitats, and representative species.

Foraging Group	General Description of Strategy	Preferred Habitat Type	Representative Species
Diving Birds	Forage by diving beneath the water’s surface to find food.	Open, deep water (lakes, rivers, coastal areas)	Grebes, cormorants, anhingas
Open Water Waders	Forage by wading in shallow water with low-density vegetation.	Shallow water with low vegetation	Herons, egrets, ibises, storks, cranes, spoonbills, avocets, stilts
Dense Vegetation Waders	Forage by wading in shallow water surrounded by dense vegetation.	Shallow water with dense vegetation	Night herons, green herons, bitterns, rails, limpkin
Dipping/Dabbling Foragers	Forage by surface dipping or “tipping” in shallow water.	Shallow water, ponds, marshes with dense vegetation	Coots, gallinules
Moist-soil Foragers	Forage in muddy or moist-soil areas along the shoreline.	Muddy areas, moist soil, shorelines	Ibises, killdeer, rails, gallinules
Aerial Piscivores/snail eaters	Use perches or flight to spot and dive for prey.	Open water, often near perches or trees	Terns, kingfishers, eagles, osprey

Colorado Wetland Bird Hotspots: Top 5 Locations for Viewing

Colorado’s diverse aquatic habitats support substantial concentrations of herons, rails, coots, grebes, and others. These ecosystems, ranging from high-altitude basin lakes to eastern prairie marshes, provide essential nesting and migratory stopover grounds for a wide variety of specialized wetland species. 

Alamosa National Wildlife Refuge: Located in the high-altitude San Luis Valley, this refuge features an extensive mosaic of freshwater marshes and oxbow ponds. It serves as a vital breeding area for high-value species. Likely sightings include the White-faced Ibis, Sora, and Black-crowned Night-Heron. 

Monte Vista National Wildlife Refuge: Situated in south-central Colorado, this site is famous for its intensively managed wetlands and wet meadows. It is a premier location for viewing massive waterfowl and crane migrations. Key birds found here include Sandhill Cranes, American Avocets, and Clark’s Grebes.

Barr Lake State Park: Located northeast of Denver, this park centers on a large freshwater reservoir surrounded by extensive marshes and cottonwood groves. It is a renowned destination for nesting raptors and waterbirds. Expect to see Bald Eagles, Great Blue Herons, and Western Grebes.

John Martin Reservoir State Park: Found in southeastern Colorado, this site encompasses a vast reservoir and the lush riparian wetlands of the Arkansas River. Its diverse habitats attract rare migrants and shorebirds. Notable residents include American White Pelicans.

Hecla Junction (Browns Canyon National Monument): Located along the Arkansas River near Salida, this area features critical riverside riparian zones and seasonal backwater pools. It is a hotspot for species favoring moving water and mountain-valley wetlands. Look for Common Mergansers.

Photo Credits:

The photographic material used in this guide was made available on various websites. Many thanks to Andrew Morffew, Mark Mochell, Elizabeth Milson, Duzan Brinkhuizen, Dennis Church, Wendy Miller, Rick From Alabama, John Benson, Mick Thompson, Steve Guttman, Victor Espinoza, Kelly Colgan-Azar, Andy Reago, Chrissy McLaren, Garry C., Linda Fortuna, Vicky DeLoach, Paul Hurtado, Tom Murray, Tom Wilberding, Kenneth Cole-Schneider, Doug Greenberg, Brian Garrett, David White, Becky Matsubara, Dan Mooney, Hal Trachtenberg, Lloyd Davis, Denis Fournier, Gregory Heaton, hharryus, Greg Lavaty, Dona Hilkey, Joshua Mayer, Aaron Maizlish, Ashley Tubs, Richard George, Sandra Minica, Nick, Jon valentine, Steve Valasek, Mitch Walters, Kurayba and Julio Mulero.

Voices:

Most recordings were made by Paul Marvin (Xeno-canto https://xeno-canto.org/contributor/RFTXRYBVBX)

References and Sources:

• Allaboutbirds.org
• eBird. (https://ebird.org/)
• Birds of the World: https://birdsoftheworld.org/bow/home
• Gill, Frank B., 1994. Ornithology – 2nd Edition, W. H. Freeman and Company.
• Sibley, David, 2000, The Sibley Guide to Birds. Alfred A. Knopf, Publisher.
• Species Longevity Data: United States Geological Survey (https://www.usgs.gov/)
• The Sibley Guide to Bird Life and Behavior, 2001. Chris Elphick, John Dunning, and David Sibley (eds). Alfred A. Knopf, New York.

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