BIRD-NOTES 53 



built up by the same secretion ; a slight excess of the 

 secretion would serve very well to fasten the egg to 

 the upper layer of down [Note 6, p. 314]. 



The Frog-Mouth, when incubating her egg, rests in 

 the characteristic Night-Jar attitude, along and not across 

 the branch bearing the nest. It is interesting to note 

 that Caprimnlgi are closely related to the Swifts, one 

 species of which, the Edible-nest Swift, Collocalia 

 fuciphaga, constructs its white nest entirely of a muci- 

 laginous substance secreted by the salivary glands. 

 Some of the nests contain a few embedded feathers, 

 whilst in others (e.g. Collocalia lowi} the proportion is 

 so great that the nests are useless from a gastronomic 

 point of view [Note 7, p. 314]. 



The nest of the Crested Swift, Macroptcryx comatus, 

 is a tiny cup of feathers and down closely cemented 

 together with mucin, and the single pure white egg, 

 which measures 20 millimeters by 15, fits accurately 

 into it. The nest itself is attached to some slender 

 twig at the top of a lofty tree, and in a stiff breeze it 

 must be jerked to and fro to a considerable extent, 

 exposing the egg to not a little danger when the 

 mother is not actually protecting it with her body. 

 Here again I would venture to suggest that the egg 

 is partially secured in position by an excess of the 

 mucilaginous matter with which the substance of the 

 nest is cemented together. 



In the bird-realm there are few more remarkable nests 

 than that made by Arachnothera longirostris, a member 

 of the Sunbird family. The species of this genus have 

 long and slender bills, and they live on spiders and 

 insects which they extract from flowers, crevices in the 

 bark of trees, and other hiding-places ; the bill un- 



