656 BIRDS into two chambers by a partition beginning at the entrance. The true carpenters are also a comparatively small group, consisting of those which excavate by their own labor holes for their nests in trees. The large and widely dis- tributed family of woodpeckers are the most familiar examples of the carpenter bird. With them are also classed the toucans of South Ame- rica, the tomtits, the wrynecks, and the nut- hatches. Among the more common examples of the birds which, without being true carpen- ters, resort to similar places for their nests, may be mentioned the sparrowhawk, the blue- bird, the purple martin, the white-bellied swallow, and the house wren of North Amer- ica, several species of owls, and many other. The platform builders are a small but distinct class, embracing most of the hawk tribe, the wood pigeons, the cuckoos of America, &c. All the eagles are true platform builders, and many of them construct elaborate and remark- able nests. The nest of the white-headed eagle is a massive structure, sometimes forming an exact cube five feet square. The martial eagle of southern Africa also constructs a large plat- form, said to be able to support the largest man. These nests are perfectly flat, with no other security against the eggs (always few in number) rolling off than the constant presence of one of the parents. The common passenger pigeon, the turtle dove, and the yellow-billed cuckoo of North America are the most famil- iar examples of this class; as also in Europe are the wood pigeons, the ringdoves, the her- ons, and the storks. Another larger class, whose architectural accomplishments are even more remarkable, are the basket-makers. Many of these exhibit an elaboration and an ingenuity beyond the power of human skill to imitate. The vireos of North America weave a cup-shaped basket nest, pendent from some convenient twig, the leaves of which conceal them from enemies. The European bullfinch, the American mock- ing bird, the red-winged blackbird, the yellow- headed troopials of North America, the ravens, crows, and magpies, and the cyanotis omnicolor of Chili, may be mentioned as among the more familiar or remarkable of this interesting group. The last-named bird attaches a nest of singular beauty and elaborateness to the stems of the large reeds of that country, constructed to re- semble so closely the ripened seed vessels of the plant as to deceive even the most wary. The locust-eating thrush of southern Africa builds a large basket fabric, containing many cells or separate nests, from 6 to 20 in number, the joint products of and occupied by as many pairs. The pensile grossbeak swings its basket nest from a pendent twig over a running stream, and makes its entrance from the bot- tom. The sociable grossbeaks unite in the construction of a large, basket-like cluster of nests, sometimes containing 200 or 300 in a single structure. The weavers are closely al- lied to the preceding class, differing chiefly in their more pensile nests, and in the superior nicety of their structure. The weaver oriole of Senegal is one of the most remarkable of this class. The Baltimore oriole of America, the Indian sparrow of southern Asia, the crested fly-catcher of southern Africa, and the yellowhammer of Europe, are among the more familiar and distinguishing instances of the weavers. Hardly distinguishable from the two preceding groups are the few species classed as tailors. The orchard oriole of America is hardly entitled to be so classed, though usually quoted as a true tailor. The best known in- stance is that of the syhia sutoria of the east- ern continent, which sews a dead leaf to a living one, and between them constructs its tiny nest. The blue yellow-back warbler of America is another remarkable tailor, though its wonderful skill is as yet little known or ap- preciated. The felt makers form quite a large and well marked group of artificers among birds. These arrange the materials of their nests, though more loosely, in the same manner as that in which are put together the fibres of felt. These materials are, to all appearances, corded together. How this is done cannot be satisfactorily explained. The chaffinch of Eu- rope, the goldfinch of America, the canary bird, and the whole family of humming birds, may be given as exemplifications of this pecu- liar and interesting group. The cementers compose a very small but well distinguished class, all the members of which, so far as is at present known, belong to the family of swal- lows. These birds secrete, from glands on each side of the head, a strongly adhesive glue, which is dissolved in their saliva, and with this unite the materials of their nests, and fasten them to their proposed sites. The chim- ney swallow of North America is the most familiar example of this group, while the escu- lent swallow of the East is the most remark- able. The dome builders might without in- convenience be merged in the several groups of weavers and basket-makers. They consist of a large number of species belonging to a great variety of families, which construct cov- ered nests, entered by holes in the side. These nests are more common in tropical than in cold countries. The marsh wrens, several of the sylticolas (as the Maryland yellow-throat), the golden-crowned thrush or oven bird, the meadow lark, and the quail, of North America, are among the most familiar representatives of this group on this continent. In Europe it embraces the common wren, the chifl'-chaff, the hay-bird, the wood wren, the sparrow, the magpie, and the bottle-tit, among its best known members. The last group is one which it is not easy to classify. The true parasites, those which, like the cuckoo of Europe, the' cow blackbirds of North America, and its con- gener of South America, never rear their own young, but intrude their offspring upon stran- gers, always laying their eggs in the nests of other species, are a small but well marked class. The larger number which resort to the
