Chap. VIII. ■ EXTERNAL DIFFERENCES. 281 



plumage the wild duck, we may conclude with confidence that 

 all the breeds are descended from A bosehas. 



I will now notice some of the peculiarities characteristic of the several 

 breeds. The eggs vary in colour; some common ducks laying pale- 

 greenish and others quite white eggs. The eggs which are first laid 

 during each season by the black Labrador duck, are tinted black, as if 

 rubbed with ink. So that with ducks, as with poultry, some degree of 

 correlation exists between the colour of the plumage and the egg-shell. 

 A good observer assured me that one year his Labrador ducks laid 

 almost perfectly white eggs, but that the yolks were this same season 

 dirty olive-green, instead of as usual of a golden yellow, so that the black 

 tint appeared to have passed inwards. Another curious case shows what 

 singular variations sometimes occur and are inherited ; Mr. Hansell 13 

 relates that he had a common duck which always laid eggs with the yolk 

 of a dark-brown colour like melted glue ; and the young ducks, hatched 

 from these eggs, laid the same kind of eggs, so that the breed had to be 

 destroyed. 



The hook-billed duck has a most remarkable appearance (see fig. of 

 skull, woodcut No. 39) ; and its peculiar beak has been inherited at least 

 since the year 1676. This structure is evidently analogous with that 



S described in the Bagadotten carrier pigeon. Mr. Brent u says that, when 



hook-billed ducks are crossed with common ducks, "many young ones 

 are produced with the upper mandible shorter than the lower, which 

 not unfrequently causes the death of the bird." A tuft of feathers on 

 the head is by no means a rare occurrence ; namely, in the true tufted 

 breed, the hook-billed, the common farmyard duck, and in a duck 

 having no other peculiarity which was sent to me from the Malayan 

 archipelago. The tuft is only so far interesting as it affects the skull, 

 which is thus rendered slightly more globular, and is perforated by 

 numerous apertures. Call-ducks are remarkable from their extra- 

 ordinary loquacity : the drake only hisses like common drakes ; neverthe- 

 less, when paired with the common duck, he transmits to his female 

 offspring a strong quacking tendency. This loquacity seems at first 

 a surprising character to have been acquired under domestication. But 

 the voice varies in the different breeds ; Mr. Brent 15 says that hook-billed 

 ducks are very loquacious, and that Eouens utter a "dull, loud, and 

 monotonous cry, easily distinguishable by an experienced ear." As the 

 loquacity of the Call-duck is highly serviceable, these birds being used in 

 decoys, this quality may have been increased by selection. For instance, 

 Colonel Hawker says, if young wild-ducks cannot be got for a decoy, "by 

 way of make-shift, select tame birds which are the most clamorous, even 

 if their colour should not be like that of wild ones." 16 It has been 



is « The Zoologist/ vols, vii., viii. p. 312. With respect to Eouens, see 



(1849-1850), p. 2353. ditto> voL u 1854> P l67> 



m 'Poultry Chronicle,' 1855, vol. iii. ie CoL Hawker's 'Instructions to 



P * i? 12 ' , ™ young Sportsmen,' quoted by Mr. Dixon 



' Poultry Chronicle,' vol. iii., 1855, in his ' Ornamental Poultry,' p. 125. 



