Merlin

The merlin is a small falcon of the Northern Hemisphere. Males typically have wingspans of 53–58 centimetres, with females slightly larger. These are swift fliers and skilled hunters that specialise in preying on small birds in the size range of sparrows to doves, as well as medium-sized shorebirds. There are numerous subspecies throughout North America and Eurasia. (Wikipedia, general species account)

The merlin breeds in the northern Holarctic, and some birds migrate to subtropical and northern tropical regions in winter. It has a long-standing presence on both sides of the Atlantic, and the genetic distinctness between Eurasian and North American populations suggests they are probably best treated as distinct species, with gene flow having ceased at least a million years ago, although more study is needed first. Colour variation in each group follows Gloger's rule. (Wikipedia, general species account)