A small bird that spends hours together on the wing, dashing through the air at great speed, frequently changing its course, now flying high, now just skimming the ground, must be either a swallow or a swift. Many people are totally at a loss to distinguish between a swallow and a swift. The two birds differ anatomically. A swift is not a passerine bird. It cannot perch. When it wants to take a rest it has to repair to its nest. Swallows, on the other hand, are fond of settling on telegraph wires. It is quite easy to distinguish between the birds when they are on the wing. A flying swift may be compared to an anchor with enormous flukes (the wings), or to an arrow (the body) attached to a bow (the wings). As the swift dashes through the air at a speed of fully 100 miles an hour, it never closes its wings to the sides of its body; it merely whips the air rapidly with the tips of them. On the other hand, the swallow, when it flies, closes its wings to its body at every stroke. Notwithstanding its greater effort, it does not move nearly so rapidly as the swift. The swifts will be considered in their proper place. Three species of swallow are likely to be seen in the Himalayas. A small ashy brown swallow with a short tail is the crag-martin (Ptyonoprogne rupestris).
The common swallow of England (Hirundo rustica) occurs in large numbers at all hill stations in the Himalayas. This bird should require no description. Its glossy purple-blue plumage, the patches of chestnut red on the forehead and throat, and the elegantly-forked tail must be familiar to every Englishman. As in England, this bird constructs under the eaves of roofs its nest of mud lined with feathers.
Not unlike the common swallow, but readily distinguishable from it in that the lower back is chestnut red, is Hirundo nepalensis--Hodgson's striated swallow, or the red-rumped swallow, as Jerdon well called it. This bird also breeds under eaves. Numbers of red-rumped swallows are to be seen daily seeking their insect quarry over the lake at Naini Tal.