 (Alaudidae), pipits (Anthus) or house sparrows (Passer domesticus)—and inexperienced yearlings always a favorite. Smaller birds will generally avoid a hunting merlin if possible. In the Cayman Islands (where it only occurs in winter), bananaquits were noted to die of an apparent heart attack or stroke, without being physically harmed, when a merlin went at them and they could not escape.
Larger birds (e.g. sandpipers, flickers and even rock pigeons as heavy as the merlin itself) and other animals—insects (especially dragonflies and moths), small mammals (especially bats and voles) and reptiles—complement its diet. These are more important outside the breeding season, when they can make up a considerable part of the merlin's diet. But for example in Norway, while small birds are certainly the breeding merlin's staple food, exceptional breeding success seems to require an abundance of Microtus voles.
Corvids are the primary threat to eggs and nestlings. Adult merlins may be preyed on by larger raptors, especially peregrine falcons (F. peregrinus), eagle-owls (e.g., great horned owl, Bubo virginianus), and larger Accipiter hawks (e.g., northern goshawk, A. gentilis). In general however, carnivorous birds avoid merlins due to their aggressiveness and agility. Their desire to drive larger raptors away from their territory is so pronounced that it is an identifying characteristic. Quoting from one popular raptor watching reference, "An observer may use this aggressive tendency for identification purposes and as a means of detection. High-flying merlins often betray themselves and distinguish themselves because they are vigorously harassing another raptor (even ones as large as the Golden Eagle)."
Breeding occurs typically in May/June. Though the pairs are monogamous at least for a breeding season, extra-pair copulations have been recorded. Most nest sites have dense vegetative or rocky cover; the merlin does not build a proper nest of its own. Most will use abandoned corvid (particularly Corvus crow and Pica magpie) or hawk nests which are in conifer or mixed tree stands. In moorland—particularly in the UK—the female will usually make a shallow scrape in dense heather to use as a nest. Others nest in crevices on cliff-faces and on the ground, and some may even use buildings.
Three to six (usually 4 or 5) eggs are laid. The rusty brown eggs average at about 40 mm × 31.5 mm (1.57 in × 1.24 in). The incubation period is 28 to 32 days. Incubation is performed by the female to about 90%; the male instead hunts to feed the family. Hatchlings weigh about 13 g (0.46 oz). The young fledge after another 30 days or so, and are dependent on their parents for up to 4 more weeks. Sometimes first-year merlins (especially males) will serve as a "nest helper" for an adult pair. More than half—often all or almost all—eggs of a clutch survive to hatching, and at least two-thirds of the hatched young fledge. However, as noted above, in years with little supplementary food only 1 young in 3 may survive to fledging. The merlin becomes sexually mature at one year of age and usually attempts to breed right away. The oldest wild bird known as of 2009 was recorded in its 13th winter.
Relationship with humansEdit
John James Audubon illustrated the merlin in the second edition of Birds of America (published in London, 1827–38) as Plate 75, under the title, "Le Petit Caporal – Falco temerarius". The image was engraved and colored by Robert Havell's London workshops. The original watercolor by Audubon was purchased by the New York History Society, where it remains as of January 2009.
William Lewin illustrates the merlin as Plate 22 in volume 1 of his Birds of Great Britain and their Eggs, published 1789 in London.
Use in falconryEdit
In medieval Europe, merlins were popular in falconry: the Book of St. Albans listed it as "the falcon for a lady", where it was noted for classic "ringing" (circling rapidly upward) pursuits of the English skylark. Though the merlin is only slightly larger than the American kestrel in dimensions, it averages about one third t