Quick Answer
Harris hawks typically have 1-5 eggs per clutch, with 2-3 being most common. The female lays the eggs over a period of several days, and incubation lasts about 35 days. Once hatched, the young hawks will stay in the nest for around 5-6 weeks before fledging. So in a single breeding season, a Harris hawk pair can raise anywhere from 1-5 chicks, though average brood size is 2-3.
How Many Eggs Do Harris Hawks Lay?
Harris hawks build nests in trees, saguaros, or on cliff ledges. The female lays between 1-5 eggs per clutch, with the average being 2-3 eggs. The eggs are whitish with brown blotches and measure about 2 inches long.
The eggs are laid over a period of several days, rather than all at once. This is known as “asynchronous hatching” and it establishes a size hierarchy among the chicks – the first hatchling will be larger and dominant over later hatchlings.
Incubation and Hatching
The female Harris hawk incubates the eggs for about 35 days before they hatch. She rarely leaves the nest during this time, while the male brings food for her.
Hatching of the chicks is also asynchronous, mirroring the staggered laying pattern. The first eggs to be laid are usually the first to hatch.
The hatchlings are altricial, which means they are helpless, blind, and covered in white downy feathers. They rely completely on their parents for warmth, protection, and food.
Development of the Chicks
For the first couple weeks after hatching, one parent (usually the female) stays at the nest to brood the chicks while the other hunts. The male brings food back for the female and chicks.
As they grow, the chicks become more active and start exploring the nest and flapping their wings to build muscle. Their flight feathers begin to grow in at around 3 weeks.
By 5-6 weeks old, the chicks are ready to take their first flights from the nest, a process called fledging. They won’t be strong fliers yet though. The parents will continue bringing the fledglings food as they learn to hunt on their own.
Typical Brood Size
So during a single breeding season, a Harris hawk pair will usually raise a brood of 2-3 chicks. Occasionally they may only have 1 chick, while other times they can raise up to 5.
The asynchronous hatching sets up a hierarchy where the oldest, largest chick gets the most food. If food is scarce, later hatchlings may not survive. So brood reduction is common in Harris hawks to ensure adequate resources for the strongest chicks.
Here is a summary of typical Harris hawk brood sizes:
- Average clutch size: 2-3 eggs
- Average number of chicks that hatch: 2-3
- Typical brood size at fledging: 2-3 chicks
- Range of brood size: 1-5 chicks
Do Both Parents Care for the Young?
Yes, Harris hawks exhibit unusual cooperative breeding behavior where several birds help care for the chicks.
A mated pair forms the nucleus of the group. Other adult “helper” birds may be previous offspring of the pair who stay with their parents rather than dispersing. Unrelated birds may also join the group.
Having this cooperative group improves the chance of breeding success. The female is able to lay more eggs because she gets more help incubating them and feeding the chicks after hatching.
The male and other helpers bring food like rabbits, rodents, and reptiles for the chicks. They pass it to the female, who tears it into smaller pieces to feed the brood.
So while the female takes the lead in incubating and brooding, it really does take a village to raise Harris hawk chicks! The more birds that help, the more chicks can be successfully fledged each season.
How Often Do Harris Hawks Breed?
In the wild, Harris hawks may start breeding as early as 2 years old, but more commonly begin around age 3. They are seasonally monogamous, pairing up with a mate each breeding season.
Harris hawks breed once per year, timing egg laying with the peak of prey availability in their desert habitat. This maximizes food resources for rearing hungry chicks.
The breeding season varies across their range, but typically runs from March-July in the Southwest U.S. and February-June in Mexico. Further south, breeding may occur as early as December.
After a successful breeding season and rearing chicks, the pair bond breaks and the hawks roam independently in the non-breeding season. They reunite with their previous mate or find a new one the next spring.
With a long reproductive lifespan of up to 12 years in the wild, Harris hawks may breed and raise up to several dozen chicks over their lifetime. Their cooperative breeding strategy allows them to maximize breeding success each season.
Conclusion
Harris hawks are prolific breeders, capable of raising as many as 2-3 chicks on average each breeding season. Key points:
- Typical clutch size is 2-3 eggs
- Incubation lasts 35 days
- Chicks fledge at 5-6 weeks
- Average brood size is 2-3
- Range is 1-5 chicks per season
- Cooperative breeding increases success
With a long breeding lifespan, a mated Harris hawk pair can produce dozens of offspring over the years with the help of their loyal band of helpers!
