306 SWALLOWS AND MARTINS 



of their first. 1 Out of thirty pairs of swallows in a village, twelve had 

 second broods, and six of these built new nests. 2 



Third broods are reared by both species, but to what extent is not 

 clear. Sometimes a late second brood, or third brood, is deserted by 

 the parents, and left to die of starvation in the nest. It has been 

 thought that this desertion exemplifies the supremacy of the migratory 

 over the parental instinct, but the explanation seems to be rather 

 that the old cease bringing food because there is none, or not enough. 

 Nature's decree is that the young must die, as they have not the 

 strength to go where food is to be found. The old have still strength, 

 and they go. So the cradle becomes a sepulchre. In the following 

 spring the forgotten bones are tossed out, and the sepulchre becomes 

 once more a cradle. 



While the parents are occupied with preparations for their second 

 broods, what are the first doing ? How they spend their days is 

 quickly told they fly, and feed, and rest. Their roosting habits 

 require a more detailed account, and this may well form part of a 

 general account of the roosting habits of the two species. 



The parent house-martins roost in their nests throughout the 

 breeding season. In the early stages of building a new nest they go 

 away to sleep, but where appears uncertain, presumably like the 

 swallow in some reed or osier-bed, where these are to be found. 

 When the nest grows large enough to accommodate them, they 

 sleep in it. During the nineteen days which the pair watched 

 by Weir spent in building, they roosted at the nest seven, and 

 away eleven days. One day one of the pair went, the other 

 remained. The later absences those that occurred after the 

 nest was advanced enough to provide a bed were due to cold or 

 windy weather, against which its half-built walls gave little shelter. 

 Once the nest is finished, no better resting-place for the night 

 could be found. It becomes less desirable when the young are born, 



1 Zoologisches Garten, 1875, 20 (H. Schacht). 

 * Ibid., 1870, 203. 



