THE SWALLOW. 183 



singular that no Swallows visit New Zealand. 

 It cannot be that the islands are too distant from 

 Australia, where several species of Swallow 

 abound, because, as Mr. Layard has remarked, 

 two, if not three, species of Cuckoo {Eudynamys 

 taitensis and Chrysococcyx lucidus) perform the 

 journey in their annual migration twice a year. 



The attachment of Swallows to the neighbour- 

 hood of water at roosting-time — which formerly 

 led to the supposition that they actually retired 

 under water for the winter — may be easily 

 accounted for by the circumstance that the 

 willow branches not only afford them most con- 

 venient perches, but enable the birds to crowd 

 close together, and so secure greater warmth to 

 individuals than they could possibly enjoy if 

 each roosted upon a separate twig in trees or 

 shrubs of different growth. 



