224 BIRD LIFE IN ENGLAND. 



gulls eat, or how many birds there are to eat the fish, but 

 what fish they eat, and what other fish have a better chance 

 in consequence." 



The economy of Nature is a mosaic from which the 

 absence of a single part loosens all the neighbouring struc- 

 ture. Were there no check upon the whiting and such other 

 destructive fish, supplied by the gulls who feed amongst 

 their young, then these might play havoc in turn with the 

 herrings. Nor does this argument clash with that of the 

 immense prolificness of food fishes, because man, demanding 

 an undoubtedly heavy toll of good fish, and not paying an 

 equivalent amount of attention to their enemies, these foes 

 must in turn be kept in place by some means such as the 

 predatory birds supply. 



Mr. Morris, the well-known author of " A History of 

 British Birds," a charming and invaluable work, has lately 

 made some calculations regarding the harm which the 

 wanton slaughter of sea birds effects, and though his deduc- 

 tions lay him open, I fear, like all such attempts, to hostile 

 criticism, they are curious and interesting. Having sum- 

 marized the number of gulls killed in a season along the 

 Yorkshire coasts alone, he adds : " If we carry on our 

 calculation still further, say, if each bird dives nine times 

 per hour (I believe eleven is the usual number) and catches 

 three whiting per hour, or one in three dives, we have : 



975 birds killed daily for " pleasure." 



109 average for professional bird killers. 



1,084 killed or wounded daily. 

 3 whiting. 



3,352 per hour. 



12 (say 12 hours per day diving for food). 



39,024 whiting destroyed per day. 

 110 days. 



4,292,640 whiting destroyed in the breeding season. 

 Mackerel, herring, sprat, and haddock are more par- 



