Birds of Prey Reproduction A. Sexual maturity. In general, smaller species begin breeding at an earlier age than larger species. Small Accipiter hawks, falcons, and harriers usually start to breed at one to two years. Buteo hawks, kites, and large falcons breed at two or three years.
Ospreys begin breeding at three or more years.
Large eagles usually start to breed at four to nine years, and vultures up to 12 years. First-time breeding may be delayed if competition for food is high or territories are unavailable. B. Reproductive behavior. Most diurnal birds of prey are monogamous. Some birds keep the same mate for several years, such as ospreys, while others have different mates each year, such as snail kites.