If all goes well, the breeding cycle of a Black Sparrowhawk takes about six months. If something happens, like the loss of eggs and the birds lay a second clutch of eggs, the time spent breeding is much longer.
In the first stages the female becomes very lethargic and the male starts doing most of the hunting. He is rewarded for his provisioning by being allowed to mate with her. This also happens when he begins to build on the nest. With each addition of sticks to the nest his reward is the same. Females will also do some nest building, especially if the male is very young and hasn’t quite grasped the concept, but mostly she will reorder his placement of sticks to her satisfaction. The nest is lined with greenery (eucalyptus leaves, pine needles etc.) which is added almost throughout the nestling stage, although this seems to vary with the individual pairs.
It is thought that because nearly all the greenery is aromatic that it helps keep parasites like lice and mites at bay. It is also thought that the greenery on the nest might serve as a signal to other Black Sparrowhawks that the territory is already occupied.
Eventually when the female is ready, she lays up to three eggs. She does most of the incubation but the male will sit on the eggs for a period each day to allow her to eat, bathe, preen and stretch her legs.
The chicks hatch between 35 and 40 days.
At first they are little bundles of fluff, but this changes very quickly. At about 45 days from hatching they are busy climbing out of the nest and into the branches getting ready for their first flight.
Once the young birds take flight they then have to learn the skill of hunting for their living. For at least the next 3 months the adults will hunt with their offspring teaching them what they need to know to survive.
By the time the youngsters reach a year old they are already beginning to grow their adult plumage. Surprisingly enough, if they can find a territory and attract a mate, they can begin to breed in their second year.
The bird on the left, who was ringed as a chick, was only 15 months old when she started nesting.
The bird on the right was so young when she started nesting that you can still see brown feathers on her chest.