NATURAL HISTORY SOCIETY OF GLASGOW. 285 



the unbridled examples. After minutely observing and counting 

 the occupants of a number of ledges, we came to the conclusion 

 that there were live common Guillemots to every bridled bird. 

 The particulars of our observations on this point will be found in 

 our Journal for that year.* We also satisfied ourselves of the 

 identity of the two forms, finding a bridled and an unbridled bird 

 most unmistakably paired on several occasions. Captain Elwes, 

 when seated in the cliff-face, by counting the birds flying past, 

 arrived at the conclusion that the bridled birds were in the pro- 

 portion of one to ten or twelve [Ibis, 1869, p. 27]. Mr. Walker 

 could only make out one in twenty [Zool., 1870, p. 2168]; whereas 

 Mr. Maclachlan, in a subsequent note to me, states his opinion that 

 "fully half of the Guillemots are bridled birds." J. A. H.-B.] 



" They only hatch one egg in the season. No nest is formed, 

 ." and the egg is laid upon the bare rock. But if by any means 

 "that egg is lost, she will lay another in seven or eight days. 

 " Should a female bird be killed early in the season, from six to ten 

 " ova are usually found in the ovary. If the first egg be taken 

 " away, the bird will not lay the second on the same place that 

 " season. I have sprinkled a lot of birds with red paint, by 

 " dipping a piece of heather into the paint, and shaking it over 

 " them. I have then gone down and taken their eggs. Other 

 " birds came there next day, and I found my marked birds, or the 

 " greater part of them, on the place which the others left. Another 

 " time I sprinkled some on one side of a point of rock with red, 

 " and those on the other side with blue paint, and found that the 

 " birds exactly changed places. Both companies were much 

 " wilder in their new abodes. 



" Usually they sit until a person is within a few yards of them. 

 " In fact, when they are ' sitting hard ' they will hardly leave the 

 " eggs. I have often walked among them when the young birds 

 " were coming out, and had to be careful that I did not tramp upon 

 " them. The parent birds make a low cooing sound, keeping the 

 " head moving up and down; every time they put down the head 

 " they touch the egg, placing it well in front of their feet. They 

 " know their own eggs perfectly well. I have several times gone 

 " on to a ledge and changed their eggs, and watched the birds 

 " return, and shift their eggs to their own respective positions 



* See also Mr. R. Gray's " Birds of West of Scotland," p. 426. 



