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
Choiseul pigeon pigeon may be a link between that species and the crowned pigeons. The adult pigeon was largely blue-grey, with a buffy orange belly and a distinctive slaty-blue crest. It is unknown how this crest was held by the bird in life. The bird's head sported a blue frontal shield surrounded by black feathers and a bicoloured beak. The wings were brown and the short tail was a blackish purple. It was described as having a beautiful rising and falling whistling call. As the bird became extinct before significant field observations could be made, not much is known about its behaviour.