NIDIFICA TION 631 
plants form of them a rude half-floating mass which is piled on some 
growing water-weed—but these birds do not spurn the duties of 
maternity. Many of the GULLS, SANDPIPERS, and PLOVERS lay their 
eggs in a shallow pit which they hollow out in the soil, and then as 
incubation proceeds add thereto a low breastwork of haulm. The 
Ringed Plover commonly places its eggs on shingle, which they so 
much resemble in colour; but when breeding on grassy uplands it 
paves the nest-hollow with small stones. PiGEONS mostly make an 
artless platform of sticks so loosely laid together that their pearly 
treasures may be perceived from beneath by the inquisitive observer. 
The Pre, as though conscious that its own thieving habits may be 
imitated by its neighbours, surrounds its nest with a hedge of thorns. 
Very many birds of very different groups bore holes in some sandy 
cliff, and at the end of their tunnel deposit their eggs with or with- 
out bedding. Such bedding, too, is very various in character ; 
thus, while the SHELD-DRAKE and the Sand-MarrTIN supply the 
softest of materials,—the one of down from her own body, the other 
of feathers collected by dint of diligent search,—the KINGFISHER 
forms in the course of incubation a couch of the undigested spiny 
fish-bones which she ejects in pellets from her own stomach. Other 
birds, as the WoopPECKERS, hew holes in living trees, even when 
the timber is of considerable hardness, and therein establish their 
nursery. Some of the Swirts secrete from their salivary glands 
a fluid which rapidly hardens as it dries on exposure to the air 
into a substance resembling isinglass, and thus furnish the “edible 
birds’ nests” that are the delight of Chinese epicures. In the 
architecture of nearly all the PASSERES, too, some salivary secretion 
seems to play an important part. By its aid they are enabled to 
moisten and bend the otherwise refractory twigs and straws and 
glue them to their place. Spiders’ webs also are employed with 
great advantage for the purpose last mentioned, but perhaps chiefly 
to attach fragments of moss and lichen so as to render the whole 
structure less obvious to the eye of the spoiler. The TAILOR-BIRD 
deliberately spins a thread, and therewith sews together the edges 
of a pair of leaves to make a receptacle for its nest; while the 
Fantail WARBLER, by a similar process of stitching—even making 
a knot at the end of the thread—unites as a sheltering canopy 
above its nest the upper ends of the grass stems amid which it is 
built. Beautiful too is the felt fabricated of fur or hairs by the 
various species of TrrmousE, while many birds ingeniously weave 
into a compact mass both animal and vegetable fibres, forming an 
admirable non-conducting medium which guards the eggs from the 
extremes of temperature outside. Such a structure may be open 
and cup-shaped, supported from below as that of the CHAFFINCH and 
and that of a nest of Fulica atra to be 61°, while the maximum temperature of the 
air that day was 58° Fahr. 
