BirdForum is the net's largest birding community, dedicated to wild birds and birding, and is absolutely FREE! You are most welcome to register for an account, which allows you to take part in lively discussions in the forum, post your pictures in the gallery and more.
Length 24-33 cm (10-13 inches), wingspan 50-67 cm, weight 150-210 g (male), 190-255 g (female)
A smallish falcon with pointed wings and relatively short tail, and a less distinct facial 'moustache' bar than most falcons, just a slightly darker slash.
Sexes differ in size, male smaller than female
Male blue-grey to blackish above, with underparts buff to orangey, streaked darker
Female brown, more heavily streaked below
Juvenile and immature similar to female
See also Subspecies, below, for variation between specific populations.
In Europe breeds in Iceland and the Faroes, throughout northern Scandinavia, sporadically in the Baltic States and widespread across northern Russia. Also very patchily in the uplands of the north and west British Isles although now extremely rare in south-west England. Dispersive in south-west Iceland and the British Isles, but elsewhere a summer visitor, with mainland European birds migrating to coastal Britain, Denmark and southern Sweden south to the Mediterranean, and on some of the larger islands and in North Africa north of Sahara. Recorded as a vagrant north to Svalbard and south to Madeira and the Canary Islands.
F. c. aesalon breeds from Europe to northwestern Siberia, winters southern Europe and the Mediterranean region. Medium tones.
F. c. insignis breeds in north-central Siberia and winters in China. Medium tones.
F. c. pacificus breeds in northeast Siberia and winters in Japan. Medium tones. Some authors consider it synonymous with F. c. insignis.
F. c. pallidus breeds in steppes of west-central Asia, winters south to India. Palest subspecies.
F. c. lymani in the mountains of central Asia (eastern Altai, Tien Shan and western China); wintering area not reported. Medium tones.
There have been proposals to split the North American group from the European group, as they have more than 2% sequence divergence; more recent data places them close, with no suggestion of paraphyly in the species with respect to any other falcons, though these authors also support this split.
Hunts over open grassland, moors, coasts and mudflats; will also hunt out to sea to catch tired migrating birds. American Merlins are known for their aggressive behavior, even during migration going out of their way to mob larger birds of prey.
Wink, M., et al. (1998). Molecular systematics of holarctic raptors (Order Falconiformes). In: Chancellor et al. (eds.): Holarctic Birds of Prey: 29-48.
Fuchs, J., Johnson, J. A., & Mindell, D. P. (2015). Rapid diversification of falcons (Aves: Falconidae) due to expansion of open habitats in the Late Miocene. Molecular Phylogenetics and Evolution 82: 166â€“182.
Warkentin, I. G., N. S. Sodhi, R. H. M. Espie, A. F. Poole, L. W. Oliphant, and P. C. James (2005). Merlin (Falco columbarius), version 2.0. In The Birds of North America (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.44
White, C.M., Boesman, P., Kirwan, G.M. & Marks, J.S. (2018). Merlin (Falco columbarius). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53231 on 8 December 2018).