THE BIRD DEPARTMENT 



357 



always the most abundant ones in the vicinity, provided 

 they lend themselves to the general type of nest which is 

 characteristic of the species. Thus the bobolinks and 

 meadowlarks use grasses, the woodland birds use leaves 

 and rootlets, and the garden birds use strings, grasses, 

 paper, etc. If some unusual material is very abundant, 

 (as like as not) the birds will select it. There are in- 

 stances of a European rook building near a clock factory 

 and using broken springs instead of twigs, of crows using 

 the old-fashioned wire stoppers of bottles, of house wrens 

 using clippings from the wire netting and hair pins, of 

 wood thrushes using rags instead of leaves and robins 

 using almost anything provided for them. The accom- 

 panying photograph of a robin's nest built largely of 

 narrow strips of paper is explainable by the nearby 

 paper factory. 



This gradual development of more elaborate and bet- 

 ter constructed nests is due probably to the change from 



ONE OF THE BEST ARCHITECTURALLY 



Nest and eggs of the yellow warbler, built entirely of soft materials and 



representing one of the higher types of nests. 



the precocial to the altricial type of young that has oc- 

 curred with the evolution of the species. The former as 

 in the case of the young grouse here shown are covered 

 with down when hatched and able to run about and fol- 

 low the parent bird so that no nest is required for their 

 protection. The latter are hatched blind, naked and help- 

 less and for a considerable time require every protection 

 and attention. Some species are less helpless than others 

 and these usually build less crude nests. The young 

 herons, for example, which are hatched in crude plat- 

 forms of sticks, soon crawl out on the surrounding 

 branches and would be able to survive even should the 



nest be entirely destroyed. Young hawks, on the other 

 hand, are helpless for nearly a month and the nest is 

 correspondingly superior. 



There remains to be mentioned those birds in which 

 the nesting instinct has become aborted, birds which 

 never build nests of their own but depend upon other 

 birds to hatch their eggs and raise their young. The 

 European cuckoo and the American cowbirds are the 



THIS TEACHES A LESSON 



The nest and eggs of the Florida gallinule. Here a platform of reeds 

 raises the nest above the water of the marsh and indicates the 

 course that may have brought birds to nesting in trees. 



best known of these parasites. The American cuckoos 

 occasionally lay eggs in each other's nests as do also some 

 of the species of wild ducks, rails, etc., but the European 

 bird never builds a nest of its own, depositing its egg in 

 some convenient place and then taking it in its bill and 

 dropping it into the nest of a hedge sparrow or other 

 small bird. Our cowbirds lay their eggs directly into the 

 nests of smaller birds such as the warblers, sparrows and 

 vireos. The young cowbird grows much more rapidly 

 than the rightful young and is considerably larger from 

 the start so that usually it gets most of the food and 

 the other young are either starved to death or crowded 

 from the nest. If the cowbird deposits its egg before 

 the owner of the nest has laid any eggs, a few species 

 of birds like the yellow warbler, redstart and vireos will 

 build another floor over the strange egg, but seldom, if 

 ever, is the egg thrown from the nest. Most birds, how- 

 ever, never seem to notice the intrusion and are quite 

 as solicitous for the young cowbird as they are for their 

 own young. 



IiIRD LIFE IN JUNE 



June is the month for nesting. Of course many species 

 begin to nest in May, some in April, and a few in 

 February or March, but in the north temperate zone, 



