Sparrows typically have two to three broods per breeding season, which takes place between March and August. The exact timing of nesting and egg laying varies by species and location, but here is a general overview of when sparrows breed and raise their young:
March – April
– Sparrows start scouting for nesting sites and building nests. House sparrows and tree sparrows are early nesters and may start nesting activities as early as late February in warmer climates.
– Egg laying typically begins in March through April depending on the species and climate.
– The first clutch is usually 3-5 eggs which are incubated for 10-14 days before hatching.
May – June
– Sparrows raise their first brood of nestlings, which fledge from the nest at 10-14 days old.
– Adults start building nests for their second brood while still feeding the fledglings from the first brood.
– Second clutch of 3-5 eggs is laid and incubated.
July – August
– Second brood fledges and adults may begin a third clutch.
– The third brood is more common in house sparrows than native North American sparrows.
– Nesting activities wind down in August as daylight decreases and preparations for autumn migration begin.
So in most cases, baby sparrows are likely to be found in nests from April through August, with peak activity in May, June and July. The exact timing depends on factors like weather, food availability, and latitude. Further details on the breeding chronology of specific sparrow species is provided below.
Breeding Biology of Common Sparrow Species
Here is a more detailed look at the nesting seasons of some of the most abundant sparrow species found across North America:
House Sparrow
The house sparrow is one of the earliest nesting birds in North America. They often build nests and begin egg-laying in late winter:
| Nest Building Starts | February to March |
| Egg Laying | March to August |
| Incubation | 11-14 days |
| Nestling Period | 11-14 days |
| Broods per Season | 2-3 |
House sparrows are prolific breeders, raising up to 3 broods per season in urban and suburban areas where food is abundant. The male continues to feed fledglings from previous broods while the female starts a new clutch.
Song Sparrow
Song sparrows breed across much of North America. They can begin nesting activities in late winter in southern parts of their range:
| Nest Building Starts | March to May |
| Egg Laying | April to August |
| Incubation | 12-14 days |
| Nestling Period | 9-12 days |
| Broods per Season | 2-3 |
Song sparrows may raise up to 3 broods per season depending on the local climate. The male cares for fledglings from previous nests while the female incubates a new clutch.
Chipping Sparrow
Chipping sparrows breed across northern North America. They have a shorter breeding season centered on early summer:
| Nest Building Starts | April to May |
| Egg Laying | May to July |
| Incubation | 11-13 days |
| Nestling Period | 10-12 days |
| Broods per Season | 1-2 |
Chipping sparrows migrate earlier than other sparrows so their breeding season is condensed into spring and early summer. They may raise a second brood farther south in their range.
Field Sparrow
Field sparrows nest in fields across eastern and central North America. Their breeding timeline is similar to that of chipping sparrows:
| Nest Building Starts | April to May |
| Egg Laying | May to July |
| Incubation | 11-13 days |
| Nestling Period | 9-12 days |
| Broods per Season | 1-2 |
Field sparrows may occasionally raise two broods per season, especially in southern parts of their range. But they more commonly just raise one brood per summer.
White-throated Sparrow
White-throated sparrows breed across Canada and the northern United States. They nest later in the season due to the colder climate:
| Nest Building Starts | May to June |
| Egg Laying | June to July |
| Incubation | 12-14 days |
| Nestling Period | 10-12 days |
| Broods per Season | 1 |
White-throated sparrows only have time to raise one brood per short northern summer. The parents work together to care for the nestlings until they fledge.
Dark-eyed Junco
Juncos breed at higher elevations and more northerly latitudes. Their breeding season is shifted later to align with conditions:
| Nest Building Starts | May to July |
| Egg Laying | June to August |
| Incubation | 12-13 days |
| Nestling Period | 10-13 days |
| Broods per Season | 1-2 |
Dark-eyed juncos may raise a second brood in July or August depending on the length of the season and food availability. Both parents help build the nest and care for young.
Ideal Conditions for Breeding
Sparrows time their breeding to match optimal conditions for nesting success. Here are some factors that help create favorable conditions for raising young:
Food abundance
– Sparrows feed mainly on seeds and insects. A good supply of these foods helps ensure adults can produce eggs and provision nestlings.
– Abundant spring rains boost vegetation growth, insect populations, and availability of freshly sprouted seeds.
Nesting sites
– Sparrows nest in shrubs, trees, and on the ground. Adequate cover from predation is key.
– Nesting habitat must be available at the right time of year for courtship, nest building, and rearing nestlings. Migratory sparrows’ arrival is timed with seasonal growth of vegetation.
Moderate weather
– Extreme cold, heat, or heavy rainfall can jeopardize egg incubation, chick survival, and finding food.
– Sparrows delay nesting until spring temperatures allow eggs and chicks to develop properly. Hot midsummer weather can inhibit late nesting.
– Sheltered nest sites help buffer from severe weather. Food is harder to find if heavy rains flood nests or make foraging difficult.
Parental Care of Nestlings
Once the eggs hatch after 10-14 days of incubation, both adult sparrows share the tasks of caring for the altricial nestlings:
Keeping nestlings warm
– Sparrow chicks hatch with no feathers and are unable to regulate their own body heat.
– Parents brood the chicks, sitting on the nest with wings spread to shelter the babies.
– As feathers grow, the chicks require less continuous brooding. But parents still shelter them at night or during cold snaps.
Feeding the nestlings
– Chicks are totally dependent on the parents to provide every meal.
– Parents gather insects, spiders, worms, snails, seeds and fruit to bring back to the nest.
– They make frequent feeding trips, up to 20-40 times per hour during peak demand.
Sanitation
– Parents remove chick’s waste sacs from the nest to keep it clean and reduce smell that might attract predators.
– Some fledglings will beg to be fed but no longer need it; parents control overfeeding with decreased responses to begging calls.
Predator defense
– Sparrows are on constant alert for threats to eggs or young, giving alarm calls or aggressively swooping at intruders.
– Nest sites in dense vegetation provide camouflage from predators like snakes, cats, raptors.
– If humans get too close to a nest, parent birds may abandon it or refuse to return to feed.
Fledging
– After 10-14 days in the nest, chicks are fully feathered and ready to take their first flights. This is the fledging stage.
– Parents encourage fledglings to stretch their wings and fly up to nearby branches. First flights are often clumsy.
– Fledglings beg loudly for food as parents lead them to forage. Parents continue to feed and teach survival skills.
– Juveniles become independent after 4-6 weeks, once they can fly competently, feed themselves, and escape predators.
– Survival rates are low for the vulnerable fledgling period. Causes of mortality include predation, accidents, starvation and bad weather.
Conclusion
Sparrows undertake intensive parental care to raise multiple broods each spring and summer. Their breeding success is closely tied to seasonal conditions like food availability, moderate temperatures, and low predation risk. While the exact nesting timeline varies by species and region, most sparrows have eggs in the nest from April through August, with a peak in May, June and July. After a brief 10-14 day incubation and nestling period, adults still have work to do, caring for and feeding fledglings for several weeks until juveniles become independent. With persistence and luck, some young sparrows will survive to breed again the following year.
