Cliff swallow

Description

The American cliff swallow's average body length is 13 cm (5.1 in),they have short legs and small bills with relatively long pointed wings.Adult cliff swallows have an overall dark brownish plumage covering both their back and wings,they have a characteristic white forehead,rich red coloured cheeks with a dark throat,basic white underparts and a buffy-coloured rump.In good lighting occasions,their crowns and mantle feathers are iridescent.The Northern population is slightly larger in body size from the Mexican cliff swallow population and differ in facial markings,where the Mexican population have a chocolate brown patch on their forehead The male and females have identical plumage,therefore sexing them must be done through palpation of the cloaca.During breeding season,the males will have a harder cloaca that is more pronounced because the seminal vesicles are swollen.In addition,during incubation females will lose feathers on their lower breast to create a warm patch for sitting on their eggs.American cliff swallows are similar in body plumage colouring to the related barn swallow species but lack the characteristic fork-shaped tail of the barn swallow prominent during flight.The cliff swallows have a square-shaped tail.Juvenile American cliff swallows have an overall similar body plumage colouring to the adults,with paler tones The juveniles lack the iridescent adult plumages,and their foreheads and throats appear speckled white.The juvenile cliff swallows’ white forehead and throat markings have high variance between unrelated individuals than those from the same clutch.These distinctive white facial markings disappear during maturity following their complex-basic moult pattern,because their pre-formative plumage is different than the basic plumage.The pre-formative facial plumage has been suggested as a possible way for parents nesting in large colonies to recognize their chicks