no THE GANNET 



for if we compute that 750 of the 855 specks on the 

 photograph are Gannets, and reckon that nearly half of 

 them — say 350 — had mates away at sea fishing, we at 

 once arrive at 1,100 Gannets as belonging to the area 

 comprised in the photograph. Multiply 1,100 by six 

 similar areas, and we get a total of 6,600 Gannets as 

 comprising the whole community. 



Another method of estimating the Ailsa Gannets has 

 been furnished by Mr. Thomson. He remembered well 

 that, very shortly before our visit, which was in June, 

 two young men, the sons of the lessee, had, by skilful climbing 

 and the use of a rope, gathered 360 Gannets' eggs from one 

 ledge, or tier of ledges, which extended a good way. My 

 companions and I saw this ledge from the land, and also 

 contemplated it from the sea, and we considered that the 

 Gannets were slightly thicker there than at any other spot 

 on the cliffs. If we allow the occupants of this ledge to 

 have numbered 850, for although a less number would suffice 

 to have produced 360 eggs some might be non-breeders, and 

 say that the Gannets on it comprised a seventh part of the 

 Ailsa community, the entire number would stand at 5,950. 



There is still a third way of estimating a Gannet settle- 

 ment, which is by comparison. Take the largest Goose 

 farm in England, where the number of Geese kept in a 

 domesticated state is registered, and compare that known 



