Bald eagles typically lay their eggs in late winter or early spring and the eaglets hatch around mid-spring. The exact timing of egg laying and hatching varies across the bald eagle’s range, but generally occurs between February and May. Bald eagles breed earlier in southern parts of their range and later in northern areas.
When do bald eagles build their nests?
Bald eagles begin constructing or repairing their massive nests in late winter in preparation for the breeding season. Nests are usually located high up in large trees near water. Bald eagle pairs often use and expand the same nest year after year.
When does egg laying occur?
Egg laying usually begins between late February and early April. Bald eagles typically lay between 1-3 eggs, with 2 being the most common. The eggs are laid with 1-4 days between each one. Incubation doesn’t start until the last egg is laid, ensuring the eaglets hatch around the same time.
How long does incubation last?
Once the last egg is laid, both parents take turns incubating and keeping the eggs warm. The incubation period lasts approximately 35 days, although it can range from 34-36 days. The female bald eagle does the majority of incubation duties.
When do the eaglets hatch?
Since incubation starts when the last egg is laid, all the eaglets should hatch within a few days of each other, if all the eggs are viable. Hatching typically occurs in mid- to late April in southern areas and mid-May in northern areas. Here are some average hatching dates for different regions:
Region | Average hatching period |
---|---|
Florida | Late March – Early April |
Chesapeake Bay area (Maryland, Virginia) | Mid- to late April |
Great Lakes (Minnesota, Wisconsin, Michigan) | Mid- to late May |
Pacific Northwest (Oregon, Washington) | Late April – Mid May |
Alaska | Late May – Early June |
How do the eaglets hatch?
About a day before hatching, the egg starts to pip, meaning the baby eaglet pokes a hole in the shell from the inside with its egg tooth. This starts the hatching process.
Over the next 12-48 hours, the eaglet continues making the hole bigger until it can break free from the rest of the shell. This vigorous process helps strengthen the eaglet and get its muscles ready to use.
The parents do not assist the eaglets in hatching – they have to do it all on their own! Once all fluffy and wet, the hatchlings are generally much smaller than their parents, averaging around 3 ounces at birth.
Development of Eaglets
After hatching, bald eagle eaglets are quite vulnerable and completely dependent on their parents for warmth, protection and food. Here is an overview of their development:
Weeks 1-4
– Covered in soft white or gray down feathers
– Very weak neck muscles, unable to hold up their head
– Remain in the nest where parents provide warmth and protection
– Parents feed eaglets by tearing up prey and the eaglets eat directly from their beak
Weeks 5-8
– Dark feathers start growing in
– Better head and neck control
– Sit up without aid and crawl around nest
– Tear up prey brought by parents
– Occasional wing flapping, building strength
Weeks 9-12
– Covered in juvenile feathers, losing downy appearance
– Very active – walking, jumping, flapping
– Tearing up prey on their own
– Parents start leaving prey in nest for eaglets to feed themselves
Week 13
– Fully feathered and ready to take first flight from the nest
– Fledging – first flight may be brief and clumsy but skills improve quickly
– Parents continue to provide food for newly fledged juveniles
Weeks 14-15
– Improving flight skills and confidence
– Start to capture own prey but still rely on parents for food through summer
– Stay close to nest and parents for protection from predators & weather
So in summary, bald eagle eaglets hatch in mid-spring, fledge by early summer, but continue to learn hunting skills and develop independence through the summer and early fall, before migration for northern birds.
Challenges for Hatchlings and Fledglings
Bald eagle hatchlings and fledglings face many threats during these vulnerable early life stages:
Weather
Extreme weather like storms, wind, heatwaves or cold snaps can directly threaten young eagles. Exposure can be deadly for small hatchlings. Older eaglets near fledging age may get blown out of the nest prematurely.
Predators
Common nest predators include raccoons, coyotes, owls, eagles from other territories, and even bears. If protective parents are away from the nest, eggs and eaglets are at risk. Fledglings on early flights are also more exposed.
Human Activity
Tree cutting, construction, roads and other encroachments near nest sites can scare away parents and leave eggs/eaglets vulnerable. Toxic chemicals and lead ammunition can impact development and survival.
Sibling Rivalry
The older, larger eaglet often gets a greater share of food and will sometimes kill its younger sibling. First hatching eaglets have a competitive edge over later hatchlings in times of low food resources.
Famine
A lack of available food from parents can slow development, lower fledging success and increase mortality. Late season ice covering waterways reduces fishing opportunities.
Disease & Parasites
Bacteria, viruses and blood parasites can make eaglets ill, especially in unsanitary nest conditions. Salmonella and avian pox are some known bald eagle diseases. Mites and lice may infest chicks.
Approximately 70-80% of bald eagle hatchlings typically survive to successfully fledge each year. Remaining healthy and safe during their first summer after fledging greatly improves an eaglet’s long-term chances.
Conclusion
Bald eagles time their breeding season so that eaglets hatch in mid-spring, when weather improves and food sources increase. After hatching, the parents devote all their efforts to protecting and feeding their helpless chicks. Within about 12-13 weeks, the eaglets grow dark flight feathers and leave the nest on their first flight. Fledgling bald eagles hone their flying and hunting skills through the summer and early fall before migrating south or toughing out the northern winter. The hatching and rearing season is an incredibly vulnerable time, but also marks the future of the bald eagle population.