[Case 61. ] 
94. BIRD GALLERY. 
difficulty in rising from the ground. The nesting-habits vary greatly 
in the different genera: the species of Cypselus (1285-1231) (of which 
our Common Swift is typical) conceal their nests in holes and under 
eaves; Panyptila (1289) constructs an enormous pendent tube of 
interwoven seeds suspended from an overhanging rock by the saliva of the 
bird; Collocalia (1244-1241) [Pl. XX.] builds in caves, the well-known 
edible nests being composed of dried secretions of the salivary glands ; 
and Macropteryx (1243) makes a small exposed nest on a branch or 
stump. The eggs, varying in number from one to five, are invariably 
pure white and devoid of gloss; the young are hatched naked. 
To the first subfamily belongs our Common Swift (Cypselus apus) 
(1235), which, like most of its allies, is migratory, arriving in Europe 
early in May and departing to its winter quarters in Africa early in 
autumn. The Alpine Swift (C. melba) (1236), an occasional visitor to 
Britain, is a well-known summer-visitor to all the high mountains of 
Central and Southern Europe, breeding in the high crags and towers. 
The group of old and young birds exhibited in the case were taken 
from the old tower of the cathedral at Berne, formerly a well-known 
breeding-place, but now replaced by a new spire. The American 
genera Panyptila (1288) and Aéronautes (4249) have the toes feathered ; 
the extraordinary nest built by the former has already been referred to. 
The Palm-Swifts (Tachornis), with the toes naked and arranged in 
pairs, attach their tiny nests, made of cotton-down and feathers, to the 
leaves of palms or to the grass roofs of native huts. A nest of 
T. phenicobia (1248) is shown in the Case. The Cheturine include the 
Spine-tailed Swifts (Chetura), with the shafts of the tail-feathers pro- 
duced into a point or spine. Of these, C. caudacuta (1241), which 
nests in Siberia and migrates to Australia, is specially interesting, 
having occurred in Britain on more than one occasion. 
The American genus Cypseloides (1240) calls for no special remark ; 
but the species of Collocalia (1244-1247), ranging from the Indo- 
Malayan countries to Australia, are interesting on account of their 
nests, which furnish the birds’-nest soup so much esteemed by the 
Chinese. As may be seen by the various specimens exhibited in the 
Case, the nests vary greatly in texture; the best, termed “ white” or 
“first quality,” are entirely glutinous and highly prized, while the 
“brown nests,” largely mixed with foreign substances, are considered 
hardly worth collecting. These birds breed in dark caves in huge 
colonies, sticking their nests close together on the rocky walls, or even 
joining them in masses. 
The last subfamily imcludes only the handsome Crested Swifts 
(Macropterya) (1248), ranging from India to Papuasia. Their peculiar 
nesting-habits have been briefly referred to above. The nest is a half. 
