183 BRITISH BIRDS. 



it. Sometimes they will visit heaps of mortar, or the dusty roads which have 

 just been watered. The outside shell of the nest is almost entirely com- 

 posed of mud. The birds do not build much at a time, but allow one layer 

 to dry before another is placed, so that each nest takes ten days or a fortnight 

 to finish. The mud is brought in little pgUets, and a few straws or dry 

 grass, or even hair, are intermixed to bind it together. Sometimes two 

 or three nests are built together ; and in some localities they are placed in 

 rows one under the other. The inside is lined with dry grass and a few 

 feathers. The nest is rounded in form, the quarter of an upright oval 

 globe, and the hole which admits the birds is at the top, generally in the 

 middle, but often in one corner. The lining materials are chiefly collected 

 as the bird is on the wing — straws and feathers which the wind blows into 

 the air. If their nest is destroyed the birds soon commence another on 

 the ruins of the old one, and this has been known to be repeated many 

 times in succession. The nest is a somewhat large structure, often 

 measuring eight or nine inches in external diameter ; the mud walls vary 

 from half an inch to three quarters of an inch in thickness. It has been 

 said that the bird sticks the little mud pellets that form the outside of its 

 nest together with its saliva. 



The Martin begins to build its nest or to repair its old one about a month 

 after its arrival, and fresh eggs may be obtained in Greece and Asia Minor 

 as early as the end of April, but seldom in this country before the end of 

 May. In the extreme north of Europe eggs are not to be obtained until 

 several weeks later. Curiously enough, in Algeria the Martin does not 

 appear to breed any earlier than in this country ; at Philippeville, on the 

 coast, Dixon remarks that their nests were unfinished in the middle of May. 

 The eggs of the Martin are from four to six in number. They are pure 

 glossy white, and the shell is very smooth. They vary in length from '8 to 

 ■7 inch, and in breadth from "55 to '52 inch, and very closely resemble those 

 of the Sand-Martin, but are a trifle larger, somewhat coarser grained, but 

 more polished. 



Both birds assist in incubating the eggs; 'and when the young are hatched 

 the exertions of the parents are taxed to the utmost to find them a suf- 

 ficient supply of food. A correspondent of Macgillivray's (Mr. T. D. 

 Weir) states that in one day they fed their young three hundred and seven 

 times ! During the whole period of incubation the male roosts in the 

 nest with the female. When the young can leave the nest they are fed 

 and tended by the old birds until they are strong on the wing, and during 

 this time the little family-party always sleep in the nest at night. The 

 young birds are fed upon the wing by their parents, and often perch on 

 posts, fences, or even telegraph-wires, waiting for the old birds to catch 

 flies for them. Probably most pairs of birds attempt to rear a second 

 brood in the season ; but in some cases the hereditary impulse to migrate 



