630 NIDIFICATION 



all being birds that breed in holes, as Alcedines, BuceroKdas, Coraciidas, 

 Cuculidse, Cypseli, Meropidae, Momotidte, Musophagidse, Pici, Todidx, 

 Trochilidx. 



The Bucconidss, Coliidse, Euryl&midse, Galbulidse and Trogonidw are 

 probably all naked. 



Menura is said to have downy nestlings. 



Opisthocomus is born with open eyes, but is fed by its parents, 

 and has an imperfect nestling plumage. 



The interesting correlation between Neossoptiles and permanent 

 Downs (see FEATHERS, p. 242) is shewn (Thier-reich, Fogel, Systemat. 

 Theil, pp. 76-85). 



NIDIFICATION, or the building of the nest in which the EGGS 

 are to be incubated and hatched, is with most Birds the beginning of 

 the real work of the breeding -season, to which SONG and its con- 

 comitant actions are but the prelude or the accompaniment ; but 

 with many it is a labour that is scamped if not shirked. Some of the 

 AUK tribe place their single egg on a bare ledge of rock, where its 

 peculiar conical shape is but a precarious safeguard when rocked by 

 the wind or stirred by the thronging crowd of its parents' fellows. 

 The Stone-CuRLEW and the NIGHTJAR deposit their eggs without the 

 slightest preparation of the soil on which they rest ; yet this is not 

 done at haphazard, for no birds can be more constant in selecting, 

 almost to an inch, the very same spot which year after year they 

 choose for their procreant cradle. 1 In marked contrast to such 

 artless care stand the wonderful structures which others build for 

 the comfort or safety of their young. But every variety of dis- 

 position may be found in the Class. The Apteryx (Kiwi) seems to 

 entrust its abnormally big egg to an excavation among the roots of 

 a tree-fern ; while a band of female OSTRICHES scrape holes in the 

 desert-sand, and therein promiscuously dropping their eggs cover 

 them with earth, and leave the task of incubation to the male, who 

 discharges the duty thus imposed upon him by night only, and 

 trusts by day to the sun's rays for keeping up the needful, fostering 

 warmth. Some MEGAPODES bury their eggs in sand, leaving them, 

 as many Reptiles do, to come to maturity by the mere warmth of the 

 ground, while others raise a huge hotbed of dead leaves wherein they 

 deposit theirs ; but in either case the young are hatched without 

 further care on the part of either parent. The GREBES and some 

 RAILS seem to avail themselves in a less degree of the heat generated 

 by vegetable decay (B. Norf. iii. p. 240), 2 and dragging from the 

 bottom or sides of the waters they frequent fragments of aquatic 



1 I make this statement literally on the experience of my brother Edward 

 and myself, but I believe it will be abundantly confirmed by the evidence of other 

 observers. 



2 Mr. Southwell found the temperature of an unincubated nest of Podicipes 

 cristatus to be 67, that of two incubated nests to be 72 and 73 respectively, 



