Breeding Immature Cooper’s Hawk

Cooper’s Hawks are found throughout the US and they have become more numerous in recent years in the Delaware Valley. These woodland raptors sport powerful rounded wings and a long tail, enabling them to maneuver with ease through the forest in pursuit of birds and small mammals. As with all raptors there is a size dimorphism between the larger females and smaller males, but in the case of Cooper’s Hawks there is considerable size difference.

It takes two years for Cooper’s Hawks to reach adulthood and attain their adult plumage – gray back, wings and tail, orange barring down the breast and belly, and a red eye. There is a pair raising a brood at John Heinz NWR, aka Tinicum, where the male is in adult plumage and the female is still in her juvenile plumage – brown back, wings and tail, thin brown streaks on the breast that thin out on the belly, and a yellow eye. This is not totally unheard of. Studies have shown that between 6% and 22% of breeding females are 1st year birds. So that juvenile near a nest, may in fact not be this years offspring, but the mother!