American Kestrel: A Complete Guide

The American Kestrel holds the distinction of being the smallest, most numerous, and widely distributed North American falcon. This tiny bird of prey encompasses two subspecies in North America and ranges from Alaska to Tierra del Fuego in the southern tip of South America. Here, I delve into the American Kestrel’s appearance, habitat use, diet, breeding, and other important aspects of its natural history. The article provides links to other articles in case you want to go deeper into the topic. Join me as we explore the marvels concealed within the intricacies of its modest American Kestrel wingspan.

Common Names: American Kestrel and Sparrow Hawk

The name “American Kestrel” is descriptive and straightforward, indicating this small falcon species native to the Americas.

American: Denotes the geographical region, in this case, the Americas. It distinguishes the kestrel as a species native to the Americas.

Kestrel: The term “kestrel” has its origins in Old French. It comes from the Old French word “crescerelle,” meaning a small raptor or kestrel. The Old French term itself has roots in the Late Latin word “crepitaculum,” referring to a small bird of prey or rattle.

Sparrow Hawk

The name “Sparrow Hawk” for the American Kestrel has historical roots that date back to early European settlers in North America. When these settlers first encountered the small falcon, they noticed its size and behavior, which included hunting small birds like sparrows. The settlers, drawing from their familiarity, perhaps with the Common Kestrel of Europe also known as Sparrow Hawk. Settlers began referring to the American Kestrel as the “Sparrow Hawk.”

It’s important to note that the name “Sparrow Hawk” is a common colloquial name and may vary regionally. While it has historical usage, today the more widely accepted and recognized name for this species is the American Kestrel.

Appearance and Identification

The appearance of the adult American Kestrel ranks among the most attractively intriguing. Many birds of prey express their sexual dimorphism through size, with females typically larger than males. However, in the case of the kestrel, there is a unique distinction – unlike many raptors, the sexes exhibit different plumages, allowing for easy identification in the field. This characteristic proves tremendously helpful in advancing our knowledge and study of these tiny predators.

The following table summarizes the key plumage differences between males and female American kestrels, emphasizing size, color variations, and distinctive markings. 

Feature	Male	Female
Overall Size:	Smaller (75-88 g, 2.6-3.1 oz)	Larger (80-105 g, 2.8-3.7 oz)
Wingspan:	32-38 cm (12.6-15 in)	36-42 cm (14.2-16.5 in)
Head:	Patterned head showing a blue-gray top of the head with rufous crown. Conspicuous black strips on both sides of the head.	Patterned head showing similar features as the male. The black stripes on both sides of the head are not as bold as in the male.
Back:	Orange-brown with bold black barring of varying thickness.	rufous-brown back finely barred with black, appearing more mottled and earthy.
Wings:	Slate-blue. Color of the wings contrasts with the range-brown of the back.	Rufous-brown that blends seamlessly with the back.
Tail:	Orange-brown without markings and a single black band at the tip.	Similar pattern and coloring to the back. The  barring on the  tail is generally finer.
Underparts:	Pale buff or cream with sparse, dark streaks and dots concentrated on the breast and sides.	Pale buff with more prominent, blurry reddish-brown streaks across the entire underside.

Juvenile American Kestrel

Another difference between the American Kestrel and other raptors is the similarity between the juvenile and adult plumage. The juvenile plumage, acquired after the down feathers, already shows the sex differences. Although duller than in the adult, the pattern and colors are similar to those of adult birds.

The two juvenile kestrels shown in this photo are newly fledged. Notice that both are male showing the orange-brown back, blue-gray wings, and spotted underparts. Another details is the variation in plumage with one bird showing warmer color in the underparts than the other.

Exploring the Kestrel’s Habitat 

The American Kestrel excels in open spaces, showcasing a mastery of diverse habitats that share essential elements: open spaces, short vegetation cover, and available perches.

• Open Fields: Vast expanses of grasslands, meadows, savannas and farmland are the Kestrel’s quintessential haunts. Here, they perch atop fence posts, power lines, and snags, scanning the landscape for unsuspecting prey.
• Grasslands: Rolling plains and prairies provide a plethora of insects and small rodents, fueling the Kestrel’s aerial acrobatics.
• Woodland Edges: Where forest meets open fields, the Kestrel finds a blend of open hunting grounds and sheltered nesting sites.

Regional Variations:

• Mountains: In regions with rugged terrain, Kestrels adapt the foraging to small clearings, nesting in  cavities on cliffs.
• Deserts: Arid landscapes pose no challenge, with Kestrels utilizing cacti and rock formations for perches and nesting.
• Urban Landscapes: Surprisingly, cities can offer suitable habitat, with parks, open spaces, and even rooftops providing hunting grounds and nesting opportunities.

The Kestrel’s habitat is not confined to these broad categories. Local factors like topography, vegetation, and prey availability play a crucial role in shaping their habitat preferences.

See more about American Kestrel Habitat.

The American Kestrel’s Shifting Range

The American Kestrel’s range dances with the rhythm of the seasons, transforming from a summer resident in the northerly reaches of its range to a winter visitor in the milder weather towards the south. Let’s unpack its shifting range across the year.

Summer range: As temperatures rise and daylight stretches, the Kestrel expand their range. During the peak of the summer, it claims vast territories in open landscapes ranging from Alaska and the Canadian tundra down to the northern reaches of Mexico.

Winter Retreat: Driven by shortening days and dwindling food resources, they embark on a southward migration, leaving the northerly reaches to settled within a smaller range. By November, much of the Kestrel population has relocated to their wintering grounds, stretching from the northern states in the United States into Mexico and Central America.

Some kestrels establish winter territories close to their summer territories. Others travel south thousands of miles to establish winter territories. Winter territories often overlaps with those of the year-round resident kestrels in the south.

American Kestrel: Master of the Hunt

The American Kestrel is not just one of the most attractive birds of prey; it’s a cunning predator with a diverse hunting toolkit. It employs a variety of tactics to spot and capture its prey.

Master of Observation

• The Silent Perch: The Kestrel patiently surveys its domain from atop fence posts, snags, or power lines. Its keen eyes, eight times sharper than ours, scan the ground below, searching for the slightest movement.
• Opportunistic Swoop: A grasshopper on a grass blade, a lizard darting through the brush – nothing escapes the Kestrel’s sharp eye. Swift dives with its  talons extended to snatch its unsuspecting prey.

Aerial Artistry

• Hovering Maestro: This is where the Kestrel truly excels. Suspended in mid-air, beating and adjusting its wings in response to the wind, the kestrel keeps its head still, allowing it to spot its prey as if perched on a pole. Below, unsuspecting insects and rodents are pinpointed, and with a sudden drop, the Kestrel claims its prey.

• Agile Acrobats: When the opportunity presents itself, the American Kestrel engages in rapid chases, weaving through scrub, light foliage, and branches to pursue smaller birds. Its lightning-fast reflexes and maneuverability leave them little chance of escape.

Dietary diversity

The Kestrel is an adaptable eater, adjusting its menu to the bounty available. Its preferred prey includes:

• Insects: Grasshoppers, crickets, beetles – an insect smorgasbord keeps the Kestrel’s energy levels high.
• Rodents: Mice, voles, and even young rabbits fall prey to the Kestrel’s aerial attacks.
• Small Birds: Sparrows, finches, and other songbirds can become targets, especially during migration or in areas with limited alternative prey.
• Reptiles: Lizards and even small snakes aren’t safe from the Kestrel’s sharp talons.

Adaptations for foraging and finding food

The Kestrel’s hunting style and menu can vary depending on habitat, season, and individual preferences. This adaptability is key to its success in a diverse and ever-changing world.

• Hovering Mastery: Their ability to hang suspended in mid-air in areas lacking perches allows Kestrels to scan for prey and launch lightning-fast dives, a skill perfectly suited for open and windy areas.
• Sharp Vision: Boasting incredible eyesight, Kestrels can spot prey from long distances, maximizing their success in vast landscapes.
• Variable Diet: From insects and rodents to lizards and even small birds, Kestrels adapt their food choices to the bounty available in their specific habitat.

• Ultraviolet Vision: The American Kestrel possesses a secret weapon – the ability to see ultraviolet light. This allows it to detect rodent urine trails, leading it to hidden feasts beneath the grass.
• Cache and Carry: To prepare for future lean times, the Kestrel will sometimes stash captured prey in hidden locations, later retrieving them for a snack.

See more about the Diet and Feeding of the American Kestrel.

American Kestrel migration

As the days shorten and autumn sets in, many Kestrels embark on journeys southward, trading open fields for warmer climes. Some populations, particularly those breeding further north, migrate long distances, traversing hundreds of miles to wintering grounds along the Gulf Coast, Mexico, and even Central America. 

Others, from milder southern regions, remain year-round residents, enjoying the bounty of their familiar landscapes.

But the Kestrel’s migration story is more than just miles and maps. It’s a tale of changing landscapes, shifting prey availability, and an innate drive to ensure survival and perpetuate their lineage. 

The following link will immerse you deeper into details of the fascinating world of Kestrel migration [link to article on Kestrel migration].

Behavior

Kestrel Courtship 

The American Kestrel boasts a hidden world of intricate social interactions. As one walks in kestrel habitat, it is likely to encounter a performing aerial display of some sort.

Mating Rituals:

• A Dazzling Air Show: Males take center stage, soaring high above their chosen territory, performing breathtaking aerial acrobatics. Dives, swoops, and tight turns in the air, a visual display captivating potential mates.
• The detail of the tail: A male’s  orange-brown tail fan wide, displaying the bold black subterminal band, drawing the attention of watching females.
• Shower of gifts: To further impress, males offer “nuptial gifts” – freshly caught prey presented to their desired partner. The female accepts the offering, assessing the provider’s prowess.

Calls

The Kestrel’s display is not limited to plumage and acrobatics. Their shrill “killy killy killy of klee klee klee” call is a staple sound echoing through open fields, serving multiple purposes:

• Territorial Defense: A stern warning to rivals, staking claim to their chosen hunting grounds and nesting sites.
• Courtship Calls: A soft, melodic variation of the “killy” is reserved for seeking the attention and approval of a potential mate. 
• Alarm Cries: A rapid series of calls erupts at the sight of potential threats, alerting his partner, fledglings and other Kestrels in neighboring territories. 

Read more about the Calls and Sound of the American Kestrel.

Territorial Defense and Acrobatics

The Kestrels’ hunting prowess seamlessly transitions into territorial defense. When intruders encroach, aerial battles ensue, featuring swooping dives, feints, and lightning-fast chases that highlight their remarkable maneuverability. These aerial encounters serve as a reminder of the assertive nature concealed within their plumage.

Preserving the American Kestrel

The American Kestrel, once commonly observed as a fiery presence in the expansive sky, is currently undergoing a decline comparable to the fading embers of its plumage. However, this situation is not a tale of surrender; it serves as a call to action, urging efforts to protect the species before it diminishes beyond recognition.

• Habitat Loss: The vanishing images of open fields, grasslands, and meadows, replaced by sprawling development and intensive agriculture, shrinks the hunting grounds and nesting sites crucial for Kestrel survival.
• Pesticide Peril: Pesticides meant for insects claim unintended victims. These toxins accumulate in the Kestrel’s food chain, weakening their bodies and reducing reproductive success.
• Deadly Roads: Highways and busy roads bisect their flight paths, transforming into silent snares. Collisions with vehicles leave a tragic toll, claiming countless Kestrels every year.

Hope Amidst the Shadows

But the Kestrel’s story isn’t one of despair. Dedicated conservation efforts are fighting back:

• Habitat Restoration: Projects are restoring lost fields and grasslands, creating safe havens for Kestrels to hunt and thrive.
• Pesticide Alternatives: Research into safer pest control methods offers a promise of a future where fields no longer hold hidden dangers.
• Public Awareness: Education campaigns are spreading the word about the plight of the Kestrel, inspiring communities to become stewards of these feathered marvels.

You Can be the Spark

Every individual can play a role in safeguarding the Kestrel’s future:

• Support Conservation Organizations: Donate to or volunteer with groups working to protect Kestrel habitats and combat threats.
• Adopt Sustainable Practices: Choose organic produce and support initiatives promoting farming practices that minimize pesticide use.
• Be a Voice for Nature: Advocate for policies that protect open spaces and prioritize wildlife conservation.
• Spread the Word: Educate your community about the Kestrel’s plight and inspire others to join the fight for their survival.

By taking action, however small, we can collectively become the wind beneath the Kestrel’s wings, ensuring their fiery spirit continues to ignite the open sky for generations to come. Remember, this is just a starting point.

References

• Ardia, D., K. Bildstein. 1997. Sex-related differences in habitat selection in wintering American kestrels, Falco sparverius. Animal Behavior, 53: 1305-1311.
• BirdLife International, 2012. “Falco sparverius” (On-line). IUCN Red List of Threatened Species. Accessed November 01, 2013 at http://www.iucnredlist.org/details/22696395/0.
• Johnsgard, P. 1990. Hawks, Eagles, and Falcons of North America. United States: Smithsonian Institution.
• Smallwood, J. A. and D. M. Bird (2020). American Kestrel (Falco sparverius), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.

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