1076 The Zoologist — February, 1868. 



years old ; yet nevertheless it takes, I find from years of observation, 

 over four years to attain the adult appearance, and in consequence, 

 I believe, irrespective of internal examination, it does not propa- 

 gate its kind till the fifth spring — that is, five years old, within a month 

 or so. In this respect it allies itself closely to the true gulls (Larus), 

 though in change of plumage it is strikingly dissimilar, slightly ap- 

 proaching, however, in this respect, the genus Xema, or blackheaded 

 gulls. I find that the generality of sea-fowl assume a dress very similar 

 to the adult the summer before they breed, though in the gulls there 

 is an immature aspect discernible about the quills called the primaries. 

 Why the plumages of this gull have been so curtailed by authors 

 (refer to any writer British or foreign) seems to me to be, that alter the 

 third summer and autumn moult, two years old, there is no glaring dis- 

 tinction between old and young; yet still it must be quite obvious to the 

 student of Nature that the plumage is not matured till after the fifth 

 autumn moult. To the student and researcher it is equally easy to 

 learn that the birds do not breed till they are five years old : this can 

 be proved conjointly by the character of the plumage, and dissection, 

 of those birds which we see in apparently adult plumage during the 

 breeding season, associating together or mixed with still younger 

 birds, often far from any breeding haunt (in this species of gull par* 

 ticularly, hundreds of miles may intervene), though it is generally more 

 natural to find them in the vicinity of bird-rocks, collected there by 

 the numbers of other sea-fowl, — a habit of the gulls,— and also because 

 these bird-rocks are by Nature placed in the direct track of the migra- 

 tory fishes on which such millions of birds feed. Authors have called 

 these apparently adult, though still, in reality, young birds, barren 

 gulls, or very old worn-out individuals. Without a critical knowledge 

 of plumage and dissection this would not seem so very improbable an 

 opinion, for young birds do not change plumage by moult till about 

 June or July — there are exceptions both ways — till late in the autumn, 

 consequently the feathers they bear at the breeding season are those 

 which have weathered the winter, and are of a necessity worn and 

 faded. A lesser blackbacked gull in the fifth summer — that is, four 

 years old — is generally, to all appearance, a tremendously old bird, the 

 dun-coloured black plumage having worn and faded to brownish 

 black, the tail, the quills and, in fact, all the plumage looking quite 

 mangy, and the most part of it dead and ready to fall out as the 

 moult advances. The lavender-backed gulls, being of a more subdued 

 colour, do not show the efl'uct so much ; still the worn plumage is the 



