The time between when a bird starts building a nest and when it lays eggs can vary greatly depending on the species. Some birds lay eggs very soon after nest completion, while others have a more extended period between nesting and egg laying. Factors like food availability, climate, mating behaviors, and evolution all influence the nesting-to-egg timeline.
Quick Answers
– Most small songbirds lay eggs 1-2 weeks after completing a nest.
– Larger birds like hawks, eagles, and owls usually lay eggs 2-4 weeks after nest building.
– Cavity nesting birds that use nest boxes or natural holes often lay eggs inside the cavity before constructing a proper nest.
– Tropical species in consistently warm climates may nest and lay on a more flexible schedule.
– The interval between nest completion and egg laying depends on factors like food supply, climate, mating habits, and threats. Birds instinctively try to maximize survival and reproduction.
Typical Timeline for Common Backyard Birds
For many common backyard breeding birds in temperate areas, the typical timeline between nesting and egg laying is short, often just a week or two.
Songbirds
Small passerine songbirds like finches, warblers, sparrows, and swallows usually have the shortest interval between completing a nest and laying eggs. Some species lay eggs just a few days after finishing the nest structure.
For example:
– American Robins build a nest for 2-6 days and lay eggs 1-3 days later.
– Barn Swallows nest for 1-2 weeks and lay eggs about 1 week after.
– Eastern Bluebirds nest for 5-10 days and lay eggs within 1-2 days of completing the nest.
– European Starlings construct a nest over 5-10 days and then lay eggs about 2 days later.
Backyard Birds
Other common backyard breeding birds have slightly longer periods between nest building and egg laying, but still typically lay eggs within 1-3 weeks.
| Species | Time Between Nesting and Eggs |
| Mourning Dove | 1-2 weeks |
| American Crow | 1-3 weeks |
| Carolina Wren | 1-2 weeks |
| Northern Mockingbird | 2-3 weeks |
| Blue Jay | 2-4 weeks |
Extended Nesting-to-Egg Timelines
While most small birds lay eggs within 1-2 weeks of finishing a nest, some species have longer delays before they start laying. This is most common in larger birds.
Raptors
Large birds of prey like hawks, eagles, and owls generally lay their eggs 2-4 weeks after nest construction. However, a few raptor species are known for quicker turnarounds. For example:
– Bald Eagles typically lay eggs 2-3 weeks after completing a large stick nest.
– Great Horned Owls lay eggs about 3-4 weeks after nesting.
– The American Kestrel has a shorter interval around 2 weeks between nesting and egg laying.
– Ospreys also lay eggs quite quickly about 1 week after finishing a nest.
Waterfowl
Many ducks and geese also fall on the longer end of the spectrum between nest completion and egg laying.
– Mallards commonly lay eggs 2-4 weeks after nest building.
– Canada Geese lay 1-2 weeks after finishing a nest.
– Wood Ducks are on the quicker end, laying eggs about 1 week after nesting.
Late Nesters
| Species | Weeks Between Nesting and Eggs |
| Great Blue Heron | 4-6 weeks |
| Sandhill Crane | 2-5 weeks |
| Pileated Woodpecker | 3-4 weeks |
| Brown Thrasher | 4-6 weeks |
Some species like herons, cranes, and woodpeckers have extended delays between nest building and egg laying up to 4-6 weeks. Their breeding cycles are adapted to match the timing of specific food sources.
Why the Variation?
Many factors account for the wide variation in the time different bird species lay eggs after completing a nest.
Climate
Birds nesting in consistently warm tropical climates often start incubating eggs as soon as possible after nest construction. But species nesting in highly seasonal habitats with cold winters and springs usually delay laying for weeks or months until temperatures warm up and food becomes abundant.
Food Availability
Birds time their breeding and nesting to coincide with peaks in the food supply needed to raise young. Species like eagles, owls, and herons lay eggs when prey like fish and small mammals are most plentiful. Songbirds nest when insects emerge or berries ripen.
Mating Habits
Some birds are monogamous and breed soon after pairing up and nest building. Others like grouse and quail form male display grounds where females mate with multiple males before nesting. This mating delay prolongs the time between nesting and egg laying.
Evolution
The nesting-to-egg-laying timeline evolved in each species to maximize reproductive success. Natural selection favors adaptations like opportunistic egg laying in swallows and extended preparation in eagles. Instincts guide birds to nest and breed on ideal schedules.
Threat Avoidance
Birds may delay egg laying to avoid common threats. For example, ducks avoid laying eggs during the peak season for mammalian egg predators. Raptors time eggs to avoid the period when blood-sucking insects that threaten nestlings are most abundant.
When Do Birds Lay Eggs Before Nesting?
While most birds lay eggs after they build a nest, some species actually lay eggs first, prior to nest construction. This occurs in situations where the egg itself is well protected.
Cavity Nesters
Birds that use tree cavities or nest boxes for nesting sites often deposit their first eggs inside the cavity and then build a nest around the eggs and incubate them.
This is common in species like:
– Woodpeckers
– Owls
– Swallows
– Bluebirds
– Wood Ducks
– Goldeneyes
Since the cavity itself provides protection, the eggs are safe while the nest is constructed. The female may even sleep directly on the eggs inside the cavity to incubate them before adding nest material.
Brood Parasites
Brood parasites like cuckoos and cowbirds lay their eggs in the nests of other bird species. They remove a host egg, lay their own, and then abandon the nest. So they lay eggs first before any nest construction.
Some other examples:
– Grebes often build a floating platform nest after laying eggs that are protected floating on the water.
– Loons and some seabirds nest right on rocky and sandy substrates after laying eggs with protective coloration.
– Male brush turkeys build massive nesting mounds of debris long before females lay eggs inside the mixture.
How Long Do Birds Take to Build Nests?
Nest building timelines also vary significantly based on the species, nesting materials, and construction effort.
Open-Cup Nests
Small songbirds weave together loose materials like grasses and twigs to form open-cup nests. This can take anywhere from just 2-3 days to two weeks.
– Chipping Sparrows build open nests in just 2-4 days.
– American Robins construct more elaborate mud and grass nests over 2-6 days.
– Baltimore Orioles weave pendulous nests over 5-8 days.
Cavity Nests
Excavating a cavity nest inside a tree trunk takes woodpeckers 1-3 weeks of pecking and hollowing.
Secondary cavity nesters reuse these cavities or natural holes:
– Eastern Bluebirds line a cavity with grass in 1-5 days.
– Tree Swallows add feathers to a nest box in just 1-2 days.
Large Stick Nests
Raptors like hawks, eagles, and ospreys build some of the largest and sturdiest stick nests. This extended construction takes 2-4 weeks for most species.
For example:
– Bald Eagles carry branches to construct massive nests over 2-4 weeks.
– Red-tailed Hawks add sticks and twigs over about 3 weeks.
– Ospreys build large structured stick nests in 2-3 weeks.
Thick-Walled Nests
Thrushes like robins and bluebirds construct nests from layers of mud reinforced with grasses. Finishing these sturdy structures takes 5-10 days.
Woven Nests
Weaverbirds and orioles are masters at weaving and knotting plant fibers into hanging woven nests that can take 1-2 weeks to finish.
| Species | Nest Building Time |
| Baltimore Oriole | 5-10 days |
| Bay-breasted Weaverbird | 10-14 days |
| Village Weaver | 4-8 days |
Conclusion
While most small songbirds lay eggs within 1-2 weeks of completing a nest, larger birds may wait 2-6 weeks before starting to lay eggs. The highly variable timeline between nesting and breeding in each species matches up with habitat, food availability, climate, mating behaviors, predator avoidance, and reproductive strategies. Birds instinctively construct nests and lay egg clutches on schedules optimized by evolution to maximize reproductive success.
