THE AMERICAN BLACK-BILLED CUCKOO. 63 



different places, giving a marbled appearance. Average of 42 eggs, 

 27.2x20.5 mm. Max. : 29.9x22.8. Min. : 22.3x18.5 (Bendire). 

 Breeding -season. — From about mid-May but often in June and 

 July. Stages of incubation vary considerably in one nest at same 

 time in some cases. Incubation. — By both sexes (Bendire). 



Food. — Almost entirely injurious insects, chiefly larvae of lepidop- 

 tera according to Beal, Forbes and King, but coleoptera, orthoptera, 

 hymenoptera, " stink-bugs," harvestmen and spiders also recorded. 



Distribution. — Ireland. — One " Kilbead " ? Killead (Antrim), 

 Sept. 25, 1871 {Zool., 1872, pp. 2943, 3022 ; Proc. Zool. Soc, 1872, 

 p. 681 ; Yarrell, Saunders, and Birds Ireland, p. 401). 



Distribution. — Abroad. — Breeds in eastern half of temperate 

 North America, from Prince Edward Island, south-east Alberta, 

 south Manitoba, south Quebec, south to Arkansas, North Carolina, 

 and mountains of Georgia. Winters in South America, casual 

 Bermudas, and has occurred as a vagrant in Italy and the Azores . 



Order STRIGES. 



Formerly generally united with the " Bapaces " or Accipitres, 

 by recent authors with the " Coraciiformes." Both views are 

 wrong, the Owls forming a sharply limited, distinct separate order, 

 the position of which must be between the " Coraciiformes " (i.e. 

 Caprimulgi, Cypseli, Coracice, Bid, etc.) and the Accipitres. 



Skeleton with many similarities to that of Accipitres, same 

 powerful feet and claws and function of legs, curved sharp bill, 

 cere, in which nostrils are situated, and others. Plumage soft 

 and long, flight noiseless, eyes large, as in Caprimulgi, but in both 

 cases adaptation to nocturnal life, not structural relationship. 

 Palate schizognathous. Skull very pneumatic. Basi-pterygoid 

 processes and vomer well developed. Sternum each side with one 

 or two incisions, without spina interna. Oil-gland bare. Feathers 

 of face forming large disk round eye, bordered by a ruff of short 

 stiff, recurved feathers originating from a deep fold of the skin 

 round the cheek. This disk is most strikingly marked in Tyto, 

 but visible in all species. Primaries 11, rectrices 12. Unlike the 

 Hawks no underdown, at all events in British species. Head 

 thick, large eyes directed forward, not very movable. Eye closed 

 by upper lid. Ears large, with strongly developed folds of the 

 skin, often asymmetric, i.e. right and left ear differently shaped. 

 Many genera in all parts of world. Eggs white, unspotted. 



Family STRIGID^]. 



The various " families " are not satisfactory, being connected 

 by intermediate forms. Therefore only one family is accepted. 



