EGGS OF BIRDS. 



257 



requisite condition of successful incubation : the heat of the sun 

 alternatino' with the cokl of nio-ht would hatch no bird's es^sc- The 

 Ostrich deposits about fifteen eggs in a hollow of the sand : the 

 male bird incubates, and the young are excluded in from fifty to 

 sixty days. The following are the periods of incubation in some 

 birds of the different orders of the class ; the female sitting where 

 not otherwise stated : — 



Species 

 American Ostrich 

 Mooruk . 

 Emeu 

 Puffin 

 Guillemot 



Hooded Merganser . 

 Sheldrake 

 Muddy Wildrake 

 Summer Duck 

 Mandarin Duck 

 Sandwich Island Goose 

 Cereopsis Goose 

 Black Swan 

 White Stork . 

 Heron 

 Dotterel . 

 Capercailzie 

 Californian Quail 

 Purple Kaleege 

 Impeyan Pheasant . 

 Crown Pigeon . 

 Ringdove 

 Cuckoo . 



Belted Kin_ 

 Martin 

 Skylark . 

 Chatfinch 

 Wren . 

 Bullfinch . 

 Starling . 

 Kaven 

 Golden Eagle 



fish( 



No. of days 

 (Ehca americana') male . . . . .35 

 (Casuarius Bennettii) male . . . .48 

 {Dromaius Novce HollayuUce) male . . 54 



(Fratercula arctica) 30 



{Uria troile) 30 



{Mergus cucuUaius) . . . . .31 



{Tadonia vulpanser) . . . . .30 



(Casarca ruiila~) 30 



(^Aix sponsa) ....... 30 



{Aix galericulafn) ...... 30 



{Bernicla sandvicensis') . . . . .31 



(Cereopsis Novce HoUandice) . . .35 



{Ci/gniis atratus) ...... 35 



(Ciconia alba) , . . . . .31 



{Ardca cinerea) 28 



(Charadrius morinellus) ..... 20 



(Telrao urogalhis) . . . . . .28 



(Calllpepla califomica') . . . . .21 



{Gallophasis Horsjieldii) . . . .24 



(Lophop/iorus Impeyaynis) . . . .28 



(Goura corotiata) . . . . . .28 



(Cohimha paluml)a) . . . . .16 



{Cucuhis canorus) by Hcdgc-Sparrow or otiicr 



Passerines 14 



(Alcedu alcyon) .16 



(Hirundo urbica) . . . .• . .13 



(Alanda arvensis) . . . . , .15 



(Fringilla ca^Iebs) . , . . . .13 



(Troglodytes vulgaris) . . . . .10 



(Pyrrhula vulgaris) . . . . .15 



(Sturnus vulgaris) . . . . .16 



{Corvus corax) 20 



(Aquila chrysaetos) . . . . .30 



Most birds nidify, i.e. prepare a receptacle foi* the eggs, to 

 aggregate them in a space that may be covered by the incuba- 

 ting body (sand-hole of Ostrich), or superadd materials to keep in 

 the warmth. The most complex ' nests ' are made by birds of 

 the singing order : and of these the pendent nests of the AYcaver- 

 Birds {PloceidcB) are, perhaps, the most perfect and remarkable 

 examples of nidification. Not only does the female construct licr 

 nest for incubation ; but the male makes his, in the form of a bec- 



VOL. II. s 



