VOL. VII.] PLUMAGES OF THE EIDER. 77 



change once a year. From fifteen to eighteen months 

 the Second Winter-plumage is gained and the bird is 

 Hke the adult male except for the pied fore -wing and 

 the black-edged curled secondaries. This plumage is 

 kept until twenty-four months when the Second Eclipse 

 is assumed. At twenty-seven months the third winter- 

 moult is in full progress, and the bird attains Adult- 

 plumage with perfect white fore-wing and curled 

 secondaries at 28-30 months. 



There is not the least doubt that, as Mr. Schioler 

 points out, the male bird becomes more brilliant in plumage 

 and more massive in skeleton in the fourth spring, but 

 to all intents and purposes it is adult at 28-30 months 

 and will pair and breed in the following spring. It may 

 be possible that the immature male may pair and breed 

 in its second year, though we have no conclusive proof 

 that it does so, for it is usual to see these immature 

 males in flocks at the pairing time ; whilst if they 

 attempt to interfere with the females, they are driven 

 off by the adult males. As I have myself seen, they go 

 through the full " show " of the adult, and are capable 

 of copulation although their testes are very small at 

 this period. Whether the eggs of females paired to these 

 two-year-old males are fertile or not I cannot say. 



Even the young males of ten months go through 

 the full courtship show, and make the courting-call 

 similar to the adult though they do not evince much 

 desire to pair with a female. Such however is not 

 always the case. On May 1st, 1912, at Scampston, 

 Mr. St. Quintin had on his river-pond four ten-months- 

 old males, and one adult female which was most anxious 

 for a mate. All the young males were " showing " and 

 calling, and the old female Hterally hunted the most 

 advanced young male until she got underneath him 

 in the water and forced him to pair. Mr. St. Quintin 

 and I witnessed the act twice. The female laid eggs, 

 but they were not fertile, so we must presume that such 

 abnormal pairing is unusual and ineffective. 



