any species which hunts them?
Peregrine falcon, Taita falcon, African hobby and wintering Eurasian hobby.
Pale crag martin
Some falcons have the speed and agility to catch swallows and martins in flight, and pale crag martins may be hunted by species such as the peregrine falcon, Taita falcon, African hobby and wintering Eurasian hobby. 
what is referred to as pale crag martin? A small passerine bird. from where did its name originate? The genus name is derived from the Ancient Greek "ptuon", "a fan", referring to the shape of the opened tail, and Procne , a mythological girl who was turned into a swallow. The specific name "obsoleta" means "worn" in Latin. where is it found? Northern Africa to Middle East extending up to Pakistan and Afghanistan. what are its sub-species? UNANSWERABLE
wiki:22002480
Pale crag martin [SEP] Predators and parasites
Some falcons have the speed and agility to catch swallows and martins in flight, and pale crag martins may be hunted by species such as the peregrine falcon, Taita falcon, African hobby and wintering Eurasian hobby. Pale crag martins often share their nesting sites with little swifts, which sometimes forcibly take over martins' nests. The argasid tick "Hyalomma marginatum" was found in pale crag martin nests on a sarcophagus and an ancient tomb in Egypt. This tick has been implicated in the transmission of Bahig virus, a pathogenic arbovirus previously thought to be transmitted only by mosquitoes. Another argasid tick, "Argas africolumbae", was found in a nest of the closely related rock martins in Kenya.