the wool of plants or animals, sometimes with other material in addition; the humming-birds and the bullfinch form beautiful nests of this fashion. Cement nests are bound together by a viscid and very adhesive secretion, which is mixed with saliva, and used to glue the materials of the nest together. The nests of the American swallow, the edible birds’ nests of the Salangani, sought after as luxuries by Chinese and others, are of this cemented type. Dome or moss nests are roofed in above and have an entrance on the side. The common wren, the water-wagtail, and the tits build on this principle. The beautiful bottle-shaped nest of the titmouse is one of the best examples. The parasite habit is well known among cuckoos and cowbirds. The nest of another bird is utilized to the future loss of the rightful inmates, and with obvious economy of labor on the part of the intruders. Thus sparrows usurp the nests of swallows, and starlings those of woodpeckers. Pheasant and partridge eggs are sometimes found in the same nest, and the same has been observed in many cases--_e. g._, gull and eider-duck. When artificial nests are forthcoming, birds are glad to be relieved of the labor of construction, and different birds thus sometimes share a common box. The resorts of birds, when convenient nooks are available, are often extremely curious. It is a well-known fact that comparatively few birds (at any rate outside of the tropics) remain in the same place all the year round. They do not hibernate, but migrate on the approach of cold. Some we know as winter visitors, returning north again in spring, most we know only in summer, for in autumn they fly to the warmer south; a third set we call “birds of passage”; for these we only know somewhat incidentally as they pass through on their way elsewhere. [Illustration: Birds of all Climes 1, Crested Grebe (_Podiceps_); 2, Toucan; 3, Hoopoe; 4, Parrot (_Melopsittacus_); 5, Barn Owl; 6, Crested Penguin; 7, King Vulture; 8, Ruff (_Pavoucella_); 9, Horned Owl; 10, Wood Duck; 11, Kingfisher; 12, Capuchin Bird; 13, Grouse; 14, Spoonbill; 15, California Quail]