IDENTIFICATION. 53 



Now, just as we picked out Pernis ftom the Falconidae by his naked 

 lores, so can we pick out Cygnus from the Anatida;. No one is likely 

 to be in doubt as to what is a Swan ; but should he be so, let him 

 look at the lores. Our Duck is not a Swan. Does he belong to the 

 genus Mergus f Is he a Merganser ? Look at his beak. Is it cut 

 into fine sharp teeth, projecting backwards as if it were a saw ? No. 

 Look at a Swan's beak ; you will see that the under mandible fits 

 right up into the upper one, and that the sides are apparently 

 grooved. Look at a Goose's beak, and you will see that the leaf- 

 shaped edges look like the edge of a lace collar. Look at a Duck's 

 beak, and you will see the plates as fine as a comb. But a Merganser's 

 beak ? It is undoubtedly a saw, and a saw such as is possessed by 

 no other British birds than the four of the Mergus genus we know 

 as the Goosander, the Smew, the Hooded Merganser, and the Red- 

 breasted Merganser, M. serrator. 



Our exainple is not a Merganser. Is he an Eider? Do the feathers 

 of his forehead come down to form a central tract along his bill ? No. 

 Is his bill spatulate, like a spatula ? Is he, in fact, a Shoveller .? No. 

 Now, we know that he has a lobe on his hind toe. If that were not 

 well developed, or if it were absent, he would belong to one of seven 

 genera. Let us run him through these. 



The group can be divided into those having the feet webs notched, 

 and those having them entire. The genera with notched webs are 

 Dajila and Qtierquedida, the former with a pointed tail, the latter with 

 a rounded tail. The genera with the unnotched webs can be divided 

 into groups — one with the tarsus reticulate all round, and one with the 

 tarsus of any other pattern. Those with the entirely reticulate tarsi 

 are the Geese, Anser and Bernida; Anser with the beak nearly as 

 long as the head, and Bei-nida with the bill much shorter than the 

 head — a distinction that may not be very great, but is really as great 

 as that adopted by such authors as are not content to treat these two 

 genera as one. There are three genera with the tarsus not completely 

 reticulate ; these are Mareca, Tadorna, and Anasj the last with a 

 wedge-shaped tail ; the first with a bill much shorter than the head ; 

 and the third with a white wing shoulder, and being, in fact, the 

 handsome Sheld Ducks, or Sheldrakes, if you so please. 



But our bird had a well-developed hind lobe, and consequently does 

 not belong to this group of seven. It must be one of the five that 

 are left. Look at its axillaries ; are they white or brown ? White. 

 That is enough. But suppose they were brown. Its genus would 

 then either be CEdemia, which are black Ducks with a tumid bill ; or 

 Clangula, which has the nostrils in the middle of the bill and i6 

 feathers in the tail ; or Harelda, which has a tapering bill, and two 

 enormously long middle feathers in a tail which has 14 in all ; or 

 Cosmonetta, which is the Harlequin Duck, so gaily striped and spotted 

 that he can be picked out at a glance from the whole of the British 

 avifauna. But a Duck with a large lobe on the hind toe and white 

 axillaries must be of the genus Fuligula. 



But which Fuligula ? He has no't a black head, and consequently 

 can be neither cristata or marila. He has not a brown back, and 

 consequently he is neither nyroca nor rufina. There is only one species 

 left and that fits him exactly :— " head, chestnut ; back, grey ; wing 

 speculum, grey " ; further, his bill is black, blue and black ; and 



