Pale crag martin to do so, it would cast doubts on their specific distinctness. There are several subspecies differing in plumage shade or size, although the differences are clinal, and races interbreed where their ranges meet. The pale crag martin of the nominate subspecies "P. o. obsoleta" is 12–13 cm (4.7–5.1 in) long with light brown upperparts, becoming paler on the lower back, and a short square tail that has small white patches near the tips of all but the central and outermost pairs of feathers. It has a pale grey throat, upper breast and underwing coverts, and the rest of the underparts
Cambridge Blue (colour) Cambridge Blue (colour) Cambridge Blue is the colour commonly used by sports teams from the University of Cambridge. There is considerable dispute regarding the exact shade of the colour that should be used. Most notably, the colour used by the Cambridge University Boat Club is different from that used by Cambridge University R.U.F.C.. The current Boat Club colour was created when Alf Twinn, Cambridge University boatman 1934–1984, added more yellow to this shade, allegedly in order to distinguish it from the rugby club's colour. The Cambridge University official colour style guide defines Cambridge Blue as Pantone 557; with RGB values