524 PERCHING BIRDS. 



those of the house-martin, although having a curious funnel at the top, so that the 

 whole structure recalls a chemist's retort. The adult male is purplish blue above, 

 the feathers of the upper back being streaked with white ; while the rump is pale 

 rufous, merging into creamy white on the upper tail-coverts ; the tail-feathers are 

 blackish, glossed with dull blue ; and the under-parts cinnamon-buff. 



. Some of the martins (Chelidon) have the tail forked, while others 



have it squared ; though all have the same short, broad bill and deep 

 gape as the swallows proper, correlated with great length of wing and weak feet. 

 The feathers of the rump are always white, and all the known species have the 

 metatarsus and toes feathered. Of this widely distributed genus, one species is 

 indigenous to Nipal, while another, the Siberian martin, breeds in Northern Asia, 

 building its nests in crowded rows under the eaves of houses, and also rearing its 

 young among the crags of limestone precipices. Blakiston's martin is a well- 

 known Japanese species, which appears to pass the winter in Borneo. No bird is 

 better known in Northern Europe than the black and white house-martin (C. urbica), 

 which usually arrives there during the first spring months of the year. The birds 

 which come to Britain are not the first migrants of their race ; for we have seen 

 house-martins nesting in Southern Europe in the middle of April, while many of 

 their companions were still migrating in squads. Most people from long observation 

 have come to believe that the house-martin never builds its nest in any position 

 except against the side of some building ; but it is a bird which adapts its habits in 

 the breeding-season to whatever locality it haj)pens to find itself established in. For 

 example, in Norway, Mr. Chapman found house-martins breeding in the crags of the 

 river banks ; and we have seen them nesting in precipitous cliffs, as they do generally 

 in some parts of Europe. The house-martin builds its nest generally during the 

 month of May, but frequentty finds its labours frustrated by the intrusion of a pair 

 of sparrows which proceed to oust the rightful owners from their domicile. The 

 nest is lined with feathers, and the eggs are pure white. It should be understood 

 that the British Isles lie directly in the line of many birds when migrating from 

 their breeding-grounds in Northern Europe to their usual winter-quarters in Africa ; 

 the birds that breed in the north of Europe naturally nesting later than those 

 which breed further south. Consequently these northerners, or at least a propor- 

 tion of their number, chiefly young birds, make their appearance in the British 

 Isles in the month of November almost as a matter of course ; and it is therefore 

 only natural to expect that a few young house-martins tarry in England until the 

 commencement of winter. Like the swallow, the house-martin is subject to some 

 variation of plumage, although albinos are much rarer than amongst swallows. 

 This species is the most gregarious of all the European swallows, and may often be 

 seen clustering in hundreds upon the roofs of houses. The adult male has the 

 crown and sides of the head, back, and wing-coverts rich bluish black ; the rump 

 and central upper tail-coverts are pure white ; the wings and tail dull black ; and 

 the chin and all the lower parts dull white. The sexes are identical in colour, but 

 the adults very unlike their sooty-brown young. 



The slender, plain -coloured martins of this group (Cotile) possess 



a small depressed bill, broadest at the base ; while the wings are long 



in proportion to the tail, which is slightly forked ; and the feet are small and 



