PHOTOGRAPHING NESTS AND EGGS 39 



they are ready. Once a young bird has left or been 

 removed from its nest, unless it is very young, it 

 will seldom consent to remain in it again. This 

 applies in particular to birds that nest on the ground, 

 less so to those that build in bushes, and least of all 

 to those which, like the woodpeckers and chicka- 

 dees, build in holes in trees. The latter seem only 

 too glad to be put back in their nest. 



There is a marked difference in the length of time 

 that young birds remain in their nests. Taking for 

 example the smaller varieties, we find that, as a rule, 

 those whose nests are on the ground not only leave 

 at a very early age, but before they are able to use 

 their wings. Young field-sparrows, blue-winged 

 warblers, and oven-birds may be found creeping 

 mouse-like among the grass and leaves in a very 

 undeveloped state, unable to fly even a few feet, and 

 scarcely able to balance themselves on a twig. 



Birds whose nests are in bushes or trees remain in 

 their nests until they are fairly well developed, usually 

 not attempting to leave until their wings are more or 

 less completely feathered, so that they are able to fly a 

 few yards. But the birds hatched in a hollow branch 

 develop rather more slowly and remain in the nest until 

 they are almost as large as their parents and are fully 

 feathered. Certain young birds, such as the screech- 

 owls, use the nest as a home, leaving it at night, 

 when they venture along the branches to receive 



