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
Pale Fire see Charles Kinbote as an alter-ego of the insane Professor V. Botkin, to whose delusions John Shade and the rest of the faculty of Wordsmith College generally condescend. Nabokov himself endorsed this reading, stating in an interview in 1962 (the novel's year of publication) that "Pale Fire" "is full of plums that I keep hoping somebody will find. For instance, the nasty commentator is not an ex-King of Zembla nor is he professor Kinbote. He is professor Botkin, or Botkine, a Russian and a madman." The novel's intricate structure of teasing cross-references leads readers to this "plum". The Index, supposedly