BLACK-HEADED GULL. 673 



a large colony of between twenty and thirty pairs was in 

 existence in a locality protected from molestation. 



In Swaledale a small community, composed of four nesting 

 pairs, was in existence at Summer Lodge Tarn until 1865, 

 and a few pairs also bred at Punchard Head in Arkengarth- 

 dale ; this latter station is probably the one referred to in the 

 Zoologist (1884, p. 139), under the impression that the birds 

 were Common Gulls, and corrected in the same volume (p. 196), 

 the recorder stating that the birds were doubtless Black- 

 headed Gulls. Another small colony of about a dozen pairs 

 was on Semer Water in Yoredale until about 1897, though, 

 unless protection is afforded them, it is probable that repeated 

 robbery will cause the birds to abandon it as a nesting resort. 



Of Yorkshire Gulleries now in occupation, besides that on 

 Skipwith Common, there is one at Locker Tarn in Wensleydale, 

 which was founded about 1888, when a single pair of birds 

 nested, and the colony has increased, until in 1902 it was com- 

 posed of about forty or fifty pairs. Another Gullery is situated 

 on the moors between Whitby and Scarborough ; it originated 

 about the year 1893 ; in 1902 there were some twenty pairs 

 nesting, but the eggs are constantly robbed, and it is to be 

 feared that the birds will be driven away if persecution does 

 not cease. I am enabled to give an illustration of this 

 place. On the fells of the north-west odd pairs occasionally 

 nest irregularly on the edges of the tarns, the most populous 

 station being on Browsholme Tarn, near Bashall Hall, where 

 several pairs are established ; a number breed near Grassington, 

 Skipton, and Oxenhope, and Mr. R. Fortune discovered 

 a new colony in the year 1904 on a lonely mountain in one of 

 the wildest parts of the fell district. 



The Black-headed Gull is an abundant species on the 

 coast in spring, and again in autumn after the young are 

 fledged, when both adult and immature birds resort to the 

 shores of the estuaries ; the bulk appear to move southward 

 as winter comes on, returning in the early part of the year. 

 In some severe winters it is extremely numerous on the 

 coast, as in February 1888, and December 1890, when, during 

 the prevalence of a hard frost, hundreds frequented the 



