128 ANIMAL LIFE UNDER WATER 



no means compensates for the injury done by 

 this gull to fish life. 



Of the 167 black-headed gulls shot at sea, 

 along the shore and in the estuaries of rivers, 

 it jyill be seen that 18.3 per cent, contained 

 earthworms, 3.8 per cent, wireworms, and 

 under 20 per cent, insects of any sort, of which 

 again a third may be considered beneficial. In 

 the matter of cereals, grain was only found in 

 2.9 per cent, of all the birds examined. 



But it may fairly be argued that the benefit 

 conferred on agriculture by the black-headed gull 

 can only be judged when the birds feed inland. 



Under exceptional circumstances, and at 

 special seasons, these birds unquestionably do 

 destroy large numbers of injurious insects, and 

 on the plate opposite are shown the contents of 

 two black-headed gulls which leave no doubt as 

 to the usefulness of the flock with which these 

 birds were feeding. But, on the other hand, in 

 1906-7 at the request of the Cumberland County 

 Council, Mr. D. Lush Thorpe, M.B.O.U., and 

 Mr. Linnaeus Hope, examined 100 black-headed 

 gulls. Of 25 birds examined in April 45 per 

 cent, contained cereals (oats) with as many as 

 100 grains in a bird. 



