The Audubon Societies 191 



X. Cementers. The Swifts are put here, and for what reason? The Chimney 

 Swift, Esculent Swift of China (which furnishes the edible birds' nests), and Java 

 Swallow or Swift are example of cement-making birds. 



XI. Dome-Builders, such as the Marsh Wren, Magpie, Clapper Rail, Cliff-chaff, 

 Maryland Yellow-throat, Gold-crested Wren (or Kinglet), Meadowlark, Bobwhite and 

 Oven-bird. 



XII. Parasite Birds, which build no nests of their own, but lay their eggs in the 

 nests of other birds. The European Cuckoo and our Cowbird are the best-known 

 parasite birds, but included under this term are also certain species which steal or 

 appropriate the nests of other birds. These are rather thieves than true parasites, 

 since they are good nest-builders ordinarily. The English or House Sparrow heads the 

 list of these thieves, while the Wrens are mentioned, and the Crow Blackbird, the latter 

 on account of its habit of frequently taking advantage of the Osprey's huge nest as a 

 hiding-place for its own. 



Now this, at best, is but a superficial and often faulty classification of the 

 different kinds of birds' nests one may find. It serves, however, to show what 

 a variety there is in the building-habits of birds, and it may whet our curiosity 

 to inquire more carefully into the details of bird-architecture. 



Keeping in mind, first, that the real home of a bird is where it nests, and, 

 second, that birds as a class show a remarkable difference in the nesting- 

 habit, not only with reference to the structure of the nest, but also in respect 

 to the date of nesting, the number of eggs laid in a clutch, the length of the 

 incubation-period, the care of the nestlings, and, in fact, every detail connected 

 with the nesting-habit, let us next find out, as nearly as we can, what things 

 are most important about a nest to make it a good cradle. 



Suppose you first try to imagine what you would want or would most 

 need if you were going to be brought up in a nest, and that may help you to 

 understand better what a remarkable structure a nest is. 



There are at least three essential points about a nest. It must be safely 

 and conveniently placed with reference to: (1) Balance; (2) Protection; 

 (3) Getting food. 



Let us think of these three points a little more closely. With very little 

 observation, we soon discover that many apparently safe and convenient 

 nesting-sites are not used by birds, while many rather unsafe places seem to 

 be chosen in preference. At first, this seems puzzling, until we remember that 

 there is probably as much variation in the choice of the nesting-site as in 

 the structure of the nest itself. But, varied as the site may be — and I have seen 

 the nest of a Robin placed thirty or forty feet high in a tree, or only two or 

 three feet from the ground, directly on the roadside, on an eaves-spout or the 

 rail of a fence, under a shed roof on a beam or directly upon the top of a trellis — 

 the nest is usually properly balanced and safely placed. Occasionally, one 

 finds a shaky or partially tipped nest which looks insecure, but such nests 

 are exceptions. The position of a nest, we may note, is of more importance 

 than its height, and the balance than either. 



A nest, in the second place, must be so situated as to protect the eggs and 



