THE GUEAT BLACK-BACKED GTJLL. • 379 



tail, which was beautifully mottled with black and white. I have in 

 different instances remarked this very handsome appearance. 



Belfast Bay. — The greater black-backed is much more frequent 

 here than the lesser black-backed gull, which would appear from 

 works upon the subject to be by far the more common species of 

 the two everywhere in England and Scotland. It should perhaps 

 rather be said that L.fuscus is rare in this estuary, than that 

 L. marinus is more common than elsewhere, but the following de- 

 tails will afford data on this point. Here old or young of this species 

 may be seen almost every day of the year, the former at all times 

 except in the breeding season, and the latter even then. The 

 period of their leaving for nidification is late. On the 5th of 

 May, 1882, I saw several, and on the 2nd of that month, in 

 1838, observed two adult and five immature birds in com- 

 pany."^ On the 30tli of June, 1842, three or four adult birds 

 appeared in the south-western side of the bay, and for an extent 

 of a few miles, only two or three gulls of any other species : 

 the L. marinus is often to be seen in the breeding season, 

 when other gulls are very scarce. Such birds as those last 

 mentioned may be considered as not breeding. At the Cope- 

 land Islands too, about the middle of June, I have remarked two 

 or three adult bii'ds, which should be brought under the same 

 category. 



But from September (and some time early in the month) until 

 May, the greater black-backed gull is daily seen in Belfast Bay 

 from the road on either side, uear to which it is driven by the 

 flowing tide, for it prefers standing on the beach to floating on the 

 waves. Along with groups of other gulls, but generally a httle 

 apart from them, and at a respectful distance from each other, a 

 pair, usually — (from which circumstance it is probable that the 

 species is monogamous) — or four adult birds will be seen. The 

 group at the outskirts of which they appear consists daily of the 

 more sociable L. argentatus, L. caniis, and L. ricUhundus — of 



* A fine adult bird which was shot in Dublin Bay on the 21st of May, came 

 under my examination (1838). On the 6th of May, 1841, I saw one in the harbour 

 at Syra (Archipelago). 



