The northern goshawk (Accipiter gentilis) is a large bird of prey that inhabits forested areas across the northern hemisphere. Goshawks have a complex life cycle that revolves around breeding, nesting, and migrating in order to survive.
What does the northern goshawk look like?
The northern goshawk is a large, powerful raptor with broad wings and a long tail. Adults have slate-blue upperparts, barred underparts, and a white eye stripe. They have bright red eyes and yellow feet and legs. Adult females are significantly larger than males. Juveniles are mottled brown above and streaked below. The goshawk’s size, up to 24 inches long with a 4-foot wingspan, and aggressive predatory nature make it an imposing bird.
Where does the northern goshawk live?
The northern goshawk has a circumpolar distribution, living across forested areas of North America, Europe, and Asia. In North America, they breed in boreal and temperate forests of Canada and the northern U.S. Some populations migrate south in winter, while others remain in their breeding territory year-round. Prime goshawk habitat consists of mature conifer and deciduous forests with relatively dense canopies.
What does the northern goshawk eat?
As an apex avian predator, the goshawk eats a variety of prey including birds, mammals, reptiles, and insects. Key avian prey includes grouse, crows, jays, woodpeckers, and passerines. Squirrels, rabbits, and hares are important mammalian foods. The goshawk hunts from perches and in flight, relying on stealth and surprise to ambush prey. It is a formidable and aggressive hunter. Prey is plucked and eaten on the ground or carried back to a feeding perch.
When does breeding occur?
Northern goshawks become sexually mature and begin breeding between one and three years of age. Courtship and pairing occur in late winter and early spring. Both members of a breeding pair engage in spectacular aerial displays including steep dives, rolls, and slow-motion flight. Nests are built new each year, typically 30-50 feet up in a large tree. Breeding season is relatively short, with most egg-laying occurring from mid-March through early April.
How many eggs does the female lay?
The typical northern goshawk clutch contains 2-4 eggs, though clutch size can range from 1-5. Eggs are bluish-white with brown blotches and average about 2 inches long. The female does all incubation and brooding, while the male provides food. Incubation lasts approximately 35 days.
How does the northern goshawk raise its young?
Goshawk chicks hatch over 2-5 days in the order they were laid. Hatchlings have thick white down and rely on the female for warmth, protection, and food. The male continues to provision the female and eventually the chicks with prey items. Chicks fledge at 34-41 days but remain dependent on the parents for another 20-30 days, learning to hunt. Juveniles reach independence and disperse from the parents’ territory after 8-10 weeks.
How long do northern goshawks live?
Wild northern goshawks may live up to 12 years though lifespans of 4-8 years are more typical. Threats to survival include starvation, predation, accidents, disease, and human activity. Survival rates are up to 60% for first-year birds and around 80% annually for adults. The oldest known wild goshawk was over 17 years old. With few predators and abundant prey, goshawks can live much longer in captivity.
What are the stages of the northern goshawk’s life cycle?
The northern goshawk goes through the following life stages:
Egg
– Laid by female in nest, early spring
Hatchling
– Hatches after 35 days incubation
– Covered in white down
– Fed by parents
– Grows flight feathers by 3-4 weeks
Fledgling
– Leaves nest at 34-41 days
– Makes first flights, parents still provide food
– Develops hunting skills over 8-10 weeks
Juvenile
– Reaches independence at 10-12 weeks
– Disperses from parents’ territory
– Highly vulnerable to starvation and predators
Immature
– Reaches sexual maturity between 1-3 years
– May migrate or remain on breeding grounds
Adult
– Breeds annually or biennially
– Defends breeding territory
– Experiences higher survival rates
– Lifespan averages 4-8 years in wild
How does the goshawk population fluctuate across the seasons?
Goshawk populations undergo seasonal fluxes as a result of breeding chronology and migratory patterns:
Spring
– Adults return to breeding areas in March/April
– Courtship displays occur
– Nest building and egg-laying occur through April
– Resident adults defend territories
Summer
– Chicks hatch in May, fledge in June/July
– Parents care for and feed dependent fledglings
– Dispersal of juveniles begins in July/August
Fall
– Juveniles complete dispersal, adults molt
– Migratory populations move south in September/October
– Residents remain on territories through winter
Winter
– Northern populations experience die-offs if prey scarce
– Migrants overwinter in southern range until spring
– Courtship begins again in February/March
How has the goshawk population changed over time?
Historic goshawk numbers were limited by natural food availability. Persecution and habitat loss caused declines from the 19th to mid-20th centuries. With legal protection and forest regrowth, populations increased across the later 1900s. However, habitat loss continues to affect goshawks in parts of their range. Here is a table summarizing population trends:
Time Period | Goshawk Population Status |
---|---|
Pre-1800s | Lower populations limited by natural prey densities |
1800s-1940s | Declines due to habitat loss and persecution as pest |
1950s-1990s | Increases and range expansions with forest regrowth |
2000s-Present | Declining in west from forest fragmentation |
Conclusion
In conclusion, northern goshawks have a dynamic life cycle that is shaped by breeding seasonality, nesting behaviors, juvenile development, and migratory patterns. Goshawk populations fluctuate across the seasons and have declined historically due to human pressures. Maintaining mature forest habitats across their range will be key to conserving these impressive raptors into the future. Their lifecycle and populations are intricately tied to the northern forest ecosystems they inhabit and rule as apex predators.