fi2 BIRDS OF TUNISIA 



species known to have been chosen as foster-parents to the Cuckoo's 

 offspring is a large one ; Mr. Bidwell gives a hst of 119 species, and 

 Dr. Key one of 146 species. 



The coloration and marking of the eggs vary greatly ; in some 

 cases, though by no means in all, they resemble the eggs of the 

 foster-parent. A light shade appears to predominate as a rule, either 

 grey tinged with greenish-blue, or grey tinged with pale rufous, and 

 with darker markings. 



The eggs are decidedly small for the size of the bird, generally 

 measuring about 23 X 18 mm. and often less. 



Shortly after it is hatched, the young Cuckoo ejects the rightful 

 occupants ■ of the nest, either nestlings or eggs, being materially 

 assisted in this operation b)' the curious depression or hollow in its 

 back, which seems to have been given it by Nature expressly and 

 solely for that purpose, as it disappears entirely as the bird grows 

 older. The young usurper then absorbs the exclusive and undivided 

 attention of its foster-parents, which, far from resenting what has 

 taken place, and obeying no doubt some mysterious, but irresistible 

 law of Nature, seem to ])ecome greatly attached to the stranger, and 

 devote themselves entire)}' to it, until it is able to shift for itself. 



COCCYSTES GLANDARIUS (Linnaeus). 

 GEEAT SPOTTED CUCKOO. 



Cuculus glandarius, Linn. Sijst. Nat. i, p. 169 (17G6) ; Malherhe, Cat. 



Bais. d'Ois. Ahj. p. 15 (1846). 

 Coccystes glandarius, Gloge)\Handb. Vdg. Eur. p. 451 (1834); Shelley, 



Cat. Birds Brit. Miis. xix, p. 212; Whitaker, Ibis, 1898, p. 126; 



Erkmger, J. f. 0. 1900, p. 19. 

 Cuculus abyssinicus, Malherhe, Cat. Bais. d'Ois. Alg. p. 15 (1846). 

 Oxylophus glandarius, LncJie, ExiA. Sci. AUj. Ois. ii, p. 74 (1867). 



Descrix>tioH. — Adult male, spring, from North Tunisia. 



Entire upper part of the head delicate bluish-grey, with a well- developed 

 crest ; I'est of upper parts greyish-brown, the secondaries and wing-coverts 

 tii)ped with white ; tail, with the exception of the two middle rectrices, 

 broadly tipped with white ; throat, upper breast, and sides of the neck 

 yellowish-white ; rest of underparts whitish, washed with grey ou the 

 flanks. 



