78 THE BRITISH NATURE BOOK 



like a timid whistle of interrogation. The nest in bushes, especially gorse, 

 and hedges is a neat structure of roots, moss, and grass, lined with hair, wool, 

 and feathers. The eggs (four to six) are a bluish white, marked with red, often 

 at the larger end. The Linnet has two broods in the year. Its food consists 

 almost entirely of seeds, though it brings larvae, etc., when feeding young. 



Martin, House. This bird, with the Swallow and Sand Martin, form one 

 family the Hirundinidce, with which the Swift, though similar in habits, is 

 not connected. The notes on the Swallow and the Sand Martin should be 

 compared ; they both come in this section. 



The House Martin is a summer visitor, very generally distributed, and is 

 distinguished from the Swallow by the white patch on the rump. Otherwise 

 the upper parts are a dark, glossy blue ; wings and tail brown ; under parts white 

 right down to the feet in fact, when seen on the ground its white " gaiters " 

 are very noticeable. The nest is found under eaves or under a ledge on a 

 cliff, and, being usually placed with the top touching the eave or ledge, is 

 really a closed nest with a hole at the side. Compare this characteristic with 

 that of the Swallow's nest. The nest, like the Swallow's, is made of mud, 

 and takes some ten days to build. Both birds male and female share in the 

 work, bringing wet mud in and on their beaks, and, beginning at the bottom, 

 pressing it on to its place with their chins (the under part of the beak and 

 throat). As this species has a sticky secretion in the mouth (which serves 

 to hold fast the insects on which they feed), it is probable that the mud they 

 use is mixed with it, and is rendered more adhesive thereby. I have noticed 

 that, when beginning to build, they place a good many "dabs" of mud on 

 the site, which begins to look as if some mischievous boy had been flinging 

 or spattering it there. There is no apparent reason for this, and the untidy 

 smudges remain after the finished nest is completed close by. Many of the 

 mud patches drop off; in fact, in one season I calculated that at least as 

 much mud fell off from a site over my door as was used for the actual nest. 

 Generally the first layer is allowed to dry before the next is added. In order 

 to help the birds one very dry year, I kept a small patch of path wetted, and 

 it was of the greatest interest to note how eagerly the birds availed themselves 

 of it. 



In order, doubtless, to add to the cohesiveness of the nest, hay and straw 

 are mixed with the mud ; the interior is lined with feathers. 



House Martins breed in colonies. Sometimes many nests may be found 

 under the same roof ; if not, on neighbouring buildings. 



The sparrow is a great enemy to the nest builders, and it is more than 

 probable that when the work is done he will take possession, keeping the 

 owners out by his stout bill. I remember as a boy reading of the revenge 

 of a pair of martins who, finding it impossible to turn the intruder out, calmly 

 closed up the entrance with fresh mud, and thus immured her in a living 

 tomb. I believe the story to be true ; but I have more than once found that 

 the best way to defeat the designs of the sparrow was to knock a hole in the 



