REED WARBLER 



the nest for short periods, generally returning with her bill full 

 of insects. About the fourth day the brooding becomes con- 

 siderably less, and in proportion the supply of food increases, 

 until both sexes are often at work together collecting and 

 bringing supplies. The faeces, enclosed in a membraneous sac, 

 are ejected by the young after the food is delivered to them, 

 and are then carried away or eaten by one or other of the 

 parents. If defaecation does not immediately take place the 

 parent touches the youngster's anus with its beak, which 

 usually has the desired effect. 



As it is possible to obtain so clear a view of the nest 

 and of the behaviour of the parents, I have been much 

 interested in noticing the method adopted by them when 

 actually delivering food to their offspring. Where there 

 are four or five young in a nest we should expect to find 

 the food delivered more or less in rotation. But this does 

 not seem to be the case. In fact it may happen that both 

 parents arrive at the nest simultaneously with food in their 

 bills, and deliver it into the gape of the same young one, 

 and also that the same bird is fed over and over again 

 until — and this will scarcely be credited — it lies with bill open, 

 apparently too exhausted to swallow so large an amount of 

 food. At other times the insects are divided more evenly, 

 three of the young perhaps receiving food from one parent ; 

 and part of it may be even withdrawn from one gape and 

 placed in another. 



The young do not all develop with equal rapidity. The 

 grow T th can easily be watched day by day, and it will be found 

 that the feathers are more developed on one bird than on 

 another, and ultimately that one is ready to leave the nest 

 before the others, and moreover does actually do so, a differ- 

 ence perhaps of one day, or in some cases even of two days, 

 intervening. By the expression " leaving the nest " I do not 

 necessarily mean deserting it, but that the bird is sufficiently 

 developed to make short excursions amongst the reeds, 

 returning again to the nursery ; nevertheless, cases have come 



4 49 



