UKBirds

Crag Martin

Ptyonoprogne rupestris

The Eurasian Crag Martin or just Crag Martin (Ptyonoprogne rupestris) is a small passerine bird in the swallow family. It is about 14 cm (5.5 in) long with ash-brown upperparts and paler underparts, and a short, square tail that has distinctive white patches on most of its feathers. It breeds in the mountains of southern Europe, northwestern Africa and southern Asia. It can be confused with the other two species in its genus, but is larger than both, with brighter tail spots and different plumage tone. Many European birds are resident, but some northern populations and most Asian breeders are migratory, wintering in northern Africa, the Middle East or India.

The Eurasian Crag Martin builds a nest adherent to the rock under a cliff overhang or increasingly onto a man-made structure. It makes a neat half-cup mud nest with an inner soft lining of feathers and dry grass. Nests are often solitary, although a few pairs may breed relativity close together at good locations. Two to five brown-blotched white eggs are incubated mainly by the female, and both parents feed the chicks. This species does not form large breeding colonies, but is gregarious outside the breeding season. It feeds on a wide variety of insects that are caught in its beak as the martin flies near to cliff faces or over streams and alpine meadows. Adults and young may be hunted and eaten by birds of prey or corvids, and this species is a host of blood-sucking mites. With its very large and expanding range and large population there are no significant conservation concerns.

This bird is closely related to the other two crag martins which share its genus, and has sometimes been considered to be the same species as one or both, although it appears that there are areas where two species' ranges overlap without hybridisation occurring. All three Ptyonoprogne crag martins are quite similar in behaviour to other Old World swallows that build mud nests, and are sometimes subsumed into the larger genus Hirundo, but this approach leads to inconsistencies in classifying other genera, particularly the house martins.

The Eurasian Crag Martin is 13-15 cm (5.1-5.9 in) long with a 32-34.5 cm (12.6-13.6 in) wingspan, and weighs an average 23 g (0.81 oz). It has ash-brown upperparts and paler underparts, and has a broader body, wings and tail than any other European swallow. The tail is short and square, with white patches near the tips of all but the central and outermost pairs of feathers. The underwing and undertail coverts are blackish, the eyes are brown, the small bill is mainly black, and the legs are brownish-pink. The sexes are alike, but juveniles have buff-brown tips to the plumage of the head, upperparts and wing coverts. This species can be distinguished from the Sand Martin by its larger size, the white patches on the tail, and its lack of a brown breast band. Where the range overlaps with that of another Ptyonoprogne species, the Eurasian Crag Martin is darker, browner and 15% larger than the Rock Martin, and larger and paler, particularly on its underparts than the Dusky Crag Martin. The white tail spots of the Eurasian Crag Martin are significantly larger than those of both its relatives.

The Crag Martin's flight appears relatively slow for a swallow. Rapid wing beats are interspersed with flat-winged glides, and its long flexible primaries give it the agility to manoeuvre near cliff faces. The average migration flight speed has been measured at 9.9 m/s (32.5 ft/s), less than the roughly 11 m/s (36 ft/s) typical for hirundines, but the data is limited. The bird often flies high, and shows the white spots as it spreads its tail. The vocalisations include short high pli, and piieh and tshir calls resembling those of the Linnet and the House Martin respectively.

The Eurasian Crag Martin breeds in mountains from Iberia and northwesternmost Africa through southern Europe, the Persian Gulf and the Himalayas to southwestern and northeastern China. Northern populations are migratory, with European birds wintering in north Africa, Senegal, Ethiopia and the Nile Valley, and Asian breeders going to southern China, the Indian subcontinent and the Middle East. Some European birds stay north of the Mediterranean, and, like martins in warmer areas such as India, Turkey and Cyprus, just move to lower ground after breeding. The breeding range is bounded by the 20 °C (68 °F) July isotherm, and wintering areas need a temperature of about 15 °C (58 °F) for enough insect food to be available. This is a rare species any distance north of its breeding areas. For example, there are only eight records from the UK, none from Ireland, and the first record for Sweden was reported as recently as 1996. South of its normal wintering range, it has occurred as a vagrant in The Gambia.

Crag Martins breed on dry, warm and sheltered cliffs in mountainous areas with crags and gorges. The typical altitude is 2,000-2,700 m (6,600-8,900 ft) but breeding occurs up to 5,000 m (16,500 ft) in Central Asia. The Eurasian Crag Martin's choice of nest sites is very similar to that of Savi's Pipistrelle, Hypsugo savii; the bird and the bat often breed in the same locations and have almost identical ranges in Europe. In South Asia, migrant Eurasian birds sometimes join with flocks of the Dusky Crag Martin and roost communally on ledges of cliffs or buildings.