The house sparrow is one of America’s most ubiquitous birds. Introduced from Europe starting in 1851, this sparrow has expanded widely. House sparrows primarily nest in cavities but are flexible and can nest in anything that resembles an enclosure, dense vines, and trees. They are aggressive and are known to displace native cavity-nesting birds. This article is intended to aid in identifying house sparrow nests and eggs.
House sparrow breeding facts
|Breeding Period:||Early May through late September.|
|Nest type:||Nests outside an enclosure have a dome shape with a side entrance. Nests inside cavities consist of a cup surrounded with coarse nesting material.|
|Substrate & Location:||Preferably inside a cavity, but can nest anywhere that resembles an enclosure at any height and location.|
|Nest measurements:||Dome-shaped nests outside cavities have an approximate diameter of 8 to 12 in.|
|Nesting Activities:||Male picks the nesting site and builds a pilot nest. Both males and females finish building the nest.|
|Egg Description:||Eggs are oval. The color ranges from light brown to greenish or bluish-white. The egg marking is variable but is generally wreathed towards the wide side with a mix of gray to brown dots and spots.|
|Egg Length and width:||0.82 in x 0.6 in.|
|Egg-laying:||It begins a day or two after nest completion. Female lays one egg every morning.|
|Clutch size:||Typically 5 eggs on average but ranges between 1 to 8 eggs.|
|Number of broods:||Multiple broods per year.|
|Incubation Period:||Typically 11 days but can extend to 14 days in regions of cold temperatures.|
Breeding range and habitat
House sparrows were first introduced in New York in 1851. They have colonized just about every urban and semi-urban area throughout North, Central, and South America.
House sparrows are year-round residents and breed where they occur. Their breeding requirements are rather flexible. They prefer cavities and enclosures to build a nest but can nest on ledges of houses and buildings, inside pipes, under awnings and roofs, and any place that offers an enclosure-like structure with space where to place a nest.
House sparrows favor open and semi-open habitats and generally do not enter woodlands. Favorite habitats include parking lots, gas stations, park-like areas, and any urban environments. They thrive in agriculture and farmland.
Migration and social behavior
House sparrows are year-round residents. Studies on house sparrow movements found that young birds are more likely to move away from the natal areas. Once sparrows reach adult age, they become sedentary.
Young birds form flocks that move about in search of suitable places to colonize and breed. Adults also form flocks that center around sources of food, roosting, and nesting sites.
House sparrows from higher and cold latitudes are known to move south during the coldest months of the year.
House sparrows are highly social, where flocks maintain a structured hierarchy among members. As shown by the amount of black on their bibs, older males occupy the highest ranking and have prime access to food, females, and nesting places. Old females rank above young males that have little to no black on their bibs.
House sparrows have a relatively long breeding period. In North America, the first eggs have been recorded in early March, and the last dependent chicks have been observed in late September. The onset of the breeding season is influenced by temperature. In higher latitudes, breeding starts later than in warmer temperatures.
House sparrow nest appearance
The nest appearance depends on nest placement. When a nest is built outside an enclosure or cavity, it adopts a round or dome-like shape of approximately 8 to 12 inches across. Nests outside an enclosure or cavity are roofed and have a side entrance that leads to a cup that holds the eggs.
The exterior part of the nest is built with coarse material, including dry grasses, twigs, pieces of plastic, paper, and strings. The cup inside the dome is lined with fine material that includes hair, mammal fur, feathers, and other fine fibers.
Nests built in cavities, nesting boxes, and other types of enclosures do not usually have any roofing but only a cup, particularly when the enclosure is small. Large enclosures tend to be filled with nesting material with a central cup.
House sparrows can build adjacent nests sharing common walls. The size of communal nesting places is variable.
House sparrows do not excavate cavities nor enhance existing structures to fit their needs. They can build their nest inside or outside cavities.
They prefer cavities or any enclosure for nesting. When these are not available, they can build a nest in trees with dense and intertwined branches, in vines, ledges of houses or buildings, spaces under awnings, traffic lights, large pipes, and in the letters of large signs.
Houses, barns, buildings, and utility structures provide plenty of nesting places to house sparrows. They readily take nesting boxes and are known to be aggressive, at times displacing other birds regardless of the nesting stage the current tenants may be.
As shown in this photo (right), house sparrows have built a nest in a bluebird box. Notice how the sparrows have filled up most of the interior with nesting material.
The initiation of nest building depends on whether males are still unmated or the pair is already formed. Unmated males find a nesting site and build a nest or start one. The male advertises his presence and the nest site by calling persistently while perched next to the nest site. Prospective females inspect the nest site and stay or move on. Once a pair is formed, the female takes over mainly to make the interior cup and lining.
Mated pairs build the nest jointly or repair the nest they used the year before or the one they used for an earlier brood.
The house sparrow eggs are oval with an approximate length of 0.82 in and breath of 0.6 in. The color and markings can vary from nest to nest and even within the same clutch.
Egg color ranges from light brown to greenish or bluish-white. Markings are also variable but are generally wreathed towards the wider side with a mix of gray to brown dots and spots.
The female house sparrow begins to lay eggs as soon as the nest is finished. Eggs are laid every day, usually in the early morning hours.
House sparrows regularly re-use the same nest for the following brood. Field observations indicate that females can start laying eggs for the next brood as soon as 8 days after the chicks of the earlier brood have left the nest. However, in some cases, it took much longer for a sparrow female to start laying eggs after the preceding brood left the nest.
The female house sparrow typically lays clutches of 5 eggs on average. But studies of nesting house sparrows found that clutches can range from 1 to 8 eggs.
Incubation of the eggs
The female sparrow begins to incubate the eggs after she lays the next-to-last egg. She roosts inside the nest upon starting to lay eggs, but she does not incubate the eggs.
When incubation starts, both males and females take turns. The male spends only a few hours incubating the eggs during the first days, but as time passes, he increases the time he spends incubating the eggs to up to 50% of the time. The female does most of the incubation initially and settles for about 50% of the time towards the end of the incubation period.
House sparrows incubate the eggs for an average of 11 days before egg hatching. In higher latitudes which normally imply cold average temperatures, eggs take longer to hatch and may take up to 14 days.
- Cordero, P. J., S. C. Griffith, J. M. Aparicio and D. T. Parker. 2000. Sexual dimorphism in House Sparrow eggs. Behav. Ecol. Sociobiol. 48: 353-357.
- Jackson, J. A., and J. Tate Jr. (1974). An analysis of nest box use by Purple Martins, House Sparrows and Starlings in eastern North America. Wilson Bulletin 86: 435–449.
- Lowther, P. E. (1979a). Growth and dispersal of nestling House Sparrows: sexual differences. Inland Bird Banding 51:23-29.
- Lowther, P. E. (1979b). The nesting biology of House Sparrows in Kansas. Kansas Ornithological Society Bulletin 30:23-26.