THE BLACK-THROATED DIVER. 133 



much narrower than those of Ducks. This enables 

 the shank to be drawn forward and pushed back, 

 with as little resistance to the water as possible. 



THE BLACK-THROATED DIVER (Colymbus arcticus] 

 is of rare occurrence in Ireland, and almost impos- 

 sible to obtain in the adult plumage, with the black 

 throat. Immature birds, though very seldom pro- 

 cured, may not perhaps be so uncommon if specially 

 sought for ; and what at a distance might be 

 taken for the Red-throated species, would, very 

 probably, now and then turn out to be the Black- 

 throated. It is slightly larger than the Red- 

 throated Diver, and when adult is very hand- 

 some ; the markings on the throat, back, and neck 

 being vivid and boldly arranged. The white 

 spots on this Diver and the Red-throated, when 

 young, are not as regularly placed side by side from 

 the neck to the tail, as in the Great Northern, but 

 are disposed straight and transversely, like snow- 

 flakes lying as they fall without any apparent 

 arrangement. The females and young of both 

 species are indistinguishable unless inspected by a 

 very competent authority. 



Mr. Williams, the taxidermist of Dublin, says, " I 

 have never in my long experience of bird-preserving 

 received an adult specimen of the Black-throated 

 Diver ; but I am confident mature birds visit 

 our bay (Dublin) every year, for they have more 

 than once been seen, and even wounded, by a 

 reliable naturalist of my acquaintance. Four im- 

 mature birds of this species are all I have had 

 through my hands." 



THE RED-THROATED DIVER (Colymbus septentrio- 



