6 INTRODUCTION. 



until the complement is made,® before which time the nest 

 should not be visited, except in cases of necessity. Most 

 birds lay four or five eggs (occasionally three or six) in a set, 

 commonly fewer in that of a second brood than before. Many 

 Wrens, Titmice, and Kingfishers often lay more ; the former 

 even ten, or very rarely twelve. Gallinaceous birds are also 

 prolific, and two or three hen-birds are said sometimes to lay 

 in the same nest. Hummingbirds, Eagles, and Pigeons, usu- 

 ally lay two eggs in a set, as do also old birds of other species, 

 particularly among the Hawks and Owls. Many sea-birds 

 have only one. If a nest be found with the same number of 

 eggs for two or three days, the proper inference generally is 

 that no more will be laid. If the egg of a Cow-bird (§ 17, 

 III) be discovered, it should be taken home, or destroyed (at 

 a distance from the nest), unless observations are to be made 

 upon the young when hatched. 



§ G. A method of finding nests, which may often be prac- 

 ticed with success, is that of "tracking" birds, when seen 

 with food for their mates or material for building. It is gen- 

 erally a wearisome and patience-exhausting process, and fre- 

 quently causes disappointment. It may be facilitated by the 

 scattering of feathers, horse-hairs, string, cotton-wool, straw, 

 etc., in places where they will attract the attention of the 

 architects in whose work you are interested. The nests of 

 Woodpeckers may often be found by tracing to its source the 

 loud rapping of the builders, or by observing on the ground 

 the chips, which are usually fresh (unless, as is rarely the 

 case, the excavation be made in an unsound tree). 



§ H. When you take eggs, pack them at once, bearing in 

 mind that the smaller ones are very delicate, and even the 

 larger ones easily broken.® If they are of the former class, 



' To this law the chief exceptions to even seven days, generally being 



are the birds of prey and the Cuckoos ; four. 



but among the smaller land-birds the ^ Much danger -will be obviated by 



average rate of laying is one a day. blowing the eggs first, when practiea- 



Thus among different species the time ble. If fresh eggs are allowed to grow 



for laying four eggs varies from three cold, or to remain long unblown, the 



