THE RETURN OF THE BIRDS 59 



does the bird capture its insect prey, that after it has 

 been on the wing but a few moments it has accumu- 

 lated sufficient to form a pellet as large as an ordinary 

 rifle bullet ; and in summer, when the young birds 

 are on the wing, this pellet is often transferred from 

 old to young in mid air. In some respects the 

 swallow has several traits distinct from most 

 migratory birds. In the case of almost all the wood- 

 warblers, which are summer migrants, the males 

 arrive and attain to their full song a week to a 

 fortnight ere the arrival of the females; but the 

 swallows almost invariably come in pairs. Their 

 coming has been marked at various stations along 

 the Mediterranean, and on through northern into 

 central and southern Africa. It is here, among the 

 myrtle and orange groves, that our little visitants 

 take their annual rest, moult, and return to us in 

 perfect plumage. 



After returning, the birds have not been long with 

 us before they commence their nests. After the 

 site is chosen small mud pellets are worked round 

 centres of bits of straw or stick, and so the nest is 

 built up lump by lump, though each layer is allowed 

 to dry before a second is added. It is not yet known 

 whether water or saliva is used as a cement in the 

 construction of the nest. When completed it is 

 thickly lined with feathers, upon which usually five 

 eggs are laid; these are white, spotted with red and 



