432 THE GANNET 



no change of plumage at nine months, and not much 

 at ten.* 



Comparatively scarce also, as was pointed out by 

 Thompson,! and also by D'Urban and Mathew,J are the 

 piebald, i.e. second-year Gannets ; yet all Gannets, before 

 reaching maturity, have to pass through this intermediate 

 piebald stage, which lasts from the age of twelve to about 

 twenty months. 



That a great many young Gannets do die somewhere is 

 an indubitable fact, although their bodies are never seen, 

 and, consequently, of actual proof there is none. But 

 they do die, and we cannot be far wrong in surmising 

 that their short existence terminates in the period between 

 September 1st and December 31st. It can only be at sea 

 that this takes place, and it is easy to understand how 

 quickly their dead bodies would be lost to view. 



Sluggishness of the Gannet. — In connection with this 

 mortality, though not explanatory of it, it should be pointed 



* Three young ones received in the down from Grassholm Island by 

 the Zoological Society, on June 27th, 1908, had, on June 21st, 1909 — 

 being then, as I supposed, twelve-and-a-half months old — black backs 

 with a few light spots still remaining, partly white heads, and nearly 

 white breasts. 



t" Birds of Ireland," TIL, p. 257. Mr. C. B. Ticehurst tells me he 

 observed Gannets in this stage off Lisbon, on April 17th and May 28th, 

 and off the Bay of Tunis on April 23rd, 1909. 



J " Birds of Devon," p. 178. 



