170 BIRD BEHAVIOUR 



varies, for in the same ternery some nests will 

 have practically no furnishing, and others be fairly 

 well provided. 



Some birds, such as the Ringed Plover when 

 breeding inland, and the Adelie Penguin of the 

 Antarctic {Pygoscelis adelies) build nests of stones, 

 which in the latter case are indeed the only available 

 material ; and the male Penguin " proposes " by 

 oflFering the hen a pebble. In the case of this 

 Penguin the nesting-site appears to belong to the 

 hen, which arrives first and takes possession ; but 

 in some cases at all events nesting-site property is 

 vested in the male bird, which brings his hen to 

 his chosen haunt, or arrives there first and guards 

 it for her, whan the two have been separated on 

 migration, as male birds generally arrive first. 



The next simplest plan to laying the eggs on the 

 ground is laying them in a hole therein, or in a 

 rock or tree, without any nest ; this is a common 

 practice, especially characteristic of Parrots, Owls, 

 and some other non-passerine perching birds, such 

 as Toucans and Hornbills. Holes often have to 

 be cleaned out, and so this practice passes naturally 

 into the widely-spread custom of the bird excavating 

 its burrow itself; in fact, the two habits are hard 

 to separate, as often the same species will occupy a 

 hole if it is there already, or make one for itself if 

 such accommodation is wanting. 



Burrowing is found in scattered members of 

 many groups, such as the Burrowing Owl (Speotyto 

 cunicularia) of America, the Sand-Martin and some 



