COMMON, HERKING, AND BLACK BACKED-GULLS 167 



being left lying about. The shearwaters are caught in the same way. 

 Mr. C. J. King, to whom I am indebted for this information, and who 

 has often watched the lesser blackbacks and their congeners engaged 

 in their murderous work, collected, one year, on a patch of ground 

 about 50 to 60 feet across, a heap of about thirty of these victims 

 and photographed them. This photograph, which I have, makes it 

 clear that the gull contents itself with the internal parts, which it 

 draws through a hole in the abdomen, leaving the rest of the body 

 intact. No doubt if puffins and shearwaters were not so abundant, 

 the lesser blackback would not be so fastidious. The great blackback 

 shows itself at times equally fastidious, but, if indisposed to play the 

 gourmet, it has this advantage over its congeners that it can save 

 itself much trouble by swallowing its bird whole, a fact sufficiently 

 proved by the presence of the heads of puffins and shearwaters among 

 the castings of indigestible matter, fur, shells, bones, etc., which, like 

 its congeners, it is in the habit of disgorging. A good photograph of 

 these ejected heads will be found on Plate XLVI. (p. 130). l The ability of 

 the great blackback to swallow comparatively large birds has, moreover, 

 been proved by post-mortem examinations. One was found to have 

 swallowed a redshank whole, legs and all, another a little-auk, which 

 was so slightly damaged by its incarceration that it was preserved by 

 a taxidermist. 2 The ventral capacity of the species may be estimated 

 from the fact that six full-sized herrings were disgorged by one and 

 the same bird. 3 The great blackback's method of capturing its victim 

 is more open and direct than that of the herring-gull and lesser 

 blackback. It suddenly pounces upon a puffin that happens to be off 

 its guard, seizes it by the neck, shakes it as a dog does a rat, and lets 

 it go. The puffin, if not sufficiently injured, may profit by its release 

 to fly off, and it sometimes escapes. As a rule, the unhappy creature 

 is seized again and again, and shaken till it can scarcely move. The 

 gull finally picks it up, flies up a hundred feet or so, and lets it drop 



1 The heads were found in castings examined by Mr. C. J. King in the Scillies. 



2 Nelson, Birds of Yorkshire, p. (584 ; Nature, 1895, 121. 3 Nelson, loc. cit. 



