COLOUR IN BIRDS AND QUADRUPEDS. 223 



placed by young ones, still sheathed ; these were of a dark lead colour, 

 appearing in some lights quite black. 



March 1834, received from Boston specimens of the Herring 

 Gull (Larus argentaius), together with a number of northern species, 

 which are now lying before me. In the majority of them, moulting 

 had progressed to a considerable extent. Mr Ord conceives Montagu, 

 who had made similar observations on this species, as "labouring under 

 the influence of a theory," when he recorded the result of his investi- 

 gations. The correctness of Montagu's assertions has been verified by 

 my own observations. 



Mr Ord has, moreover, doubted the accuracy of Montagu's observa- 

 tions on the changes of plumage in a Black Stork, taken in England. 

 The latter gentleman stated that this bird continued very gradually to 

 moult during summer and winter; that in the month of March, the 

 violet and purple feathers appeared on the back, and that the whole 

 upper parts had nearly assumed this beautiful plumage by the 1st of 

 April. He supposes that it could not have moulted, although Mon- 

 tagu asserts that to be the fact, and considers this statement of Montagu 

 as " affording one of the most apposite illustrations of the fact of a 

 change of colour in mature plumage, that could well be desired." I 

 have not been able to regard it in this light. Admitting that all the 

 species of Storks and Herons moult but once a year, of which we have 

 no certainty, it does not appear difficult to account for the slow pace 

 with which this individual assumed its bright colours. It will be re- 

 collected that it was a foreigner, retained in captivity during winter, 

 in the moist, cold climate of England. Had it been left at liberty to 

 pursue its migrations to Africa, where this species hyemates, it would 

 probably have sooner attained full plumage. It is, moreover, highly 

 probable that this stork was changing from the young to the adult 

 plumage ; in this case the process was similar to that of the Plotus an- 

 hinga, referred to in a former part of this paper, and of the Blue Gros- 

 beak, now in my possession ; the latter having been gradually moulting 

 and receiving its bright colours during the winter and spring. Young 

 birds always shed and renew their feathers more slowly and irregu- 

 larly than the old ; and in this instance, where we have a process so 

 similar in other species, we cannot avoid giving credence to the decla- 



VI. — 3 F 



