Merlin (bird) this phenomenon is due to the fluctuations of supplementary food stocks discussed above. Merlin (bird) The merlin ("Falco columbarius") is a small species of falcon from the Northern Hemisphere, with numerous subspecies throughout North America and Eurasia. A bird of prey once known colloquially as a pigeon hawk in North America, the merlin breeds in the northern Holarctic; some migrate to subtropical and northern tropical regions in winter. Males typically have wingspans of , with females being slightly larger. They are swift fliers and skilled hunters who specialize in preying on small birds in the size range of sparrows to
Passenger pigeon the genus "Accipiter" and falcons pursued and preyed upon pigeons in flight, which in turn executed complex aerial maneuvers to avoid them; Cooper's hawk was known as the "great pigeon hawk" due to its successes, and these hawks allegedly followed migrating passenger pigeons. While many predators were drawn to the flocks, individual pigeons were largely protected due to the sheer size of the flock, and overall little damage could be inflicted on the flock by predation. Despite the number of predators, nesting colonies were so large that they were estimated to have a 90% success rate if not disturbed. After