The rock martin (Ptyonoprogne fuligula) is a small passerine bird in the swallow family that is resident in central and southern Africa. It breeds mainly in the mountains, but also at lower altitudes, especially in rocky areas and around towns, and, unlike most swallows, it is often found far from water. It is long, with mainly brown plumage, paler-toned on the upper breast and underwing coverts, and with white "windows" on the spread tail in flight. The sexes are similar in appearance, but juveniles have pale fringes to the upperparts and flight feathers. The former northern subspecies are smaller, paler, and whiter-throated than southern African forms, and are now usually split as a separate species, the pale crag martin. The rock martin hunts along cliff faces for flying insects using a slow flight with much gliding. Its call is a soft twitter.
The rock martin builds a deep bowl nest on a sheltered horizontal surface, or a neat quarter-sphere against a vertical rock face or wall. The nest is constructed with mud pellets and lined with grass or feathers, and may be built on natural sites under cliff overhangs or on man-made structures such as buildings, dam walls, culverts and bridges. It is often reused for subsequent broods or in later years. The rock martin is a solitary breeder, and is not gregarious, but small groups may breed close together in suitable locations. The two or three eggs of a typical clutch are white with brown and grey blotches, and are incubated by both adults for 16–19 days prior to hatching. Both parents then feed the chicks. Fledging takes another 22–24 days, but the young birds will return to the nest to roost for a few days after the first flight.
The rock martin is often predated on by several fast and agile species of falcon, such as the hobby, and it sometimes carries parasites. Because it is common within its large range with an apparently stable population, it is assessed as a least-concern species on the IUCN Red List.
Taxonomy
The rock martin was formally described in 1842 as Hirundo fuligula by German physician, explorer and zoologist Martin Lichtenstein and was moved to the new genus Ptyonoprogne by German ornithologist Heinrich Gustav Reichenbach in 1850. Its nearest relatives are the three other members of the genus, the pale crag martin (P. obsoleta) of north Africa, the dusky crag martin (P. concolor) of southern Asia and the Eurasian crag martin (P. rupestris). The genus name is derived from the Ancient Greek (), "a fan", referring to the shape of the opened tail, and Procne (), a mythological girl who was turned into a swallow. The specific name fuligula means "sooty-throated", from the Latin , "soot", and , "throat".
The four Ptyonoprogne species are members of the swallow family, and are placed in the subfamily Hirundininae, which comprises all swallows and martins except the very distinctive river martins. DNA sequence studies suggest that there are three major groupings within the Hirundininae, broadly correlating with the type of nest built. The groups are the "core martins" including burrowing species like the sand martin, the "nest-adopters", which are birds like the tree swallow that utilise natural cavities, and the "mud nest builders". The Ptyonoprogne species construct open mud nests and therefore belong to the last group. Hirundo species also build open nests, Delichon house martins have a closed nest, and the Cecropis and Petrochelidon swallows have retort-like closed nests with an entrance tunnel.
The genus Ptyonoprogne is closely related to the larger swallow genus, Hirundo, but a DNA analysis published in 2005 showed that a coherent enlarged Hirundo should contain all mud-builder genera. Although the nests of the Ptyonoprogne crag martins resemble those of typical Hirundo species like the barn swallow, the DNA research suggested that if the Delichon house martins are considered to be a separate genus, as is normally the case, Cecropis, Petrochelidon and Ptyonoprogne should also be split off.