GEOGRAPHICAL GROUPS 173 



Museum; but under C. s. maccormicki (p. 122) a male and a female are recorded as 

 having been taken by Charcot's expedition at Deception Island on December 2, 1909. 

 In the report of Charcot's second expedition the list of maccormicki contains no corre- 

 sponding data, but two examples, one of each sex, of Megalestris antarctica are included 

 as having been killed at Deception on the date quoted (Gain, 1915, pp. 109-10). Since 

 it is obvious that these two birds were quite accidentally added to the list of maccormicki 

 which was sent to Lowe and Kinnear from Paris, I include them in my list of Brown 

 Skuas from the South Shetlands. 



Since there are only twelve specimens caution must be observed, but on reference 

 to the figures it will be noticed that there appears to be a natural tendency for the birds 

 to fall into two groups of six each, one of which has a tarsal length of over 70 mm. while 

 in the other it is under 70 mm. The two groups are separated in the Table (p. 167). 



The interesting point is that the measurements of the larger group, that is, with the 

 longer tarsus, incline towards those of lonnbergi, while those of the smaller birds are 

 nearer to the dimensions of the Falkland Islands subspecies, C. s. antarctica. 



Plumage distinctions between the two South Shetland groups are non-existent, they 

 do not differ materially from any other series of skins : one of the smaller birds, it may 

 be remarked, has a particularly bright collar such as is found in some Falkland specimens. 



CONCLUSIONS 



There is found in the Falklands a smaller form of Brown Skua which frequently has 

 a fairly bright collar of yellow acuminate feathers on the neck ; the wing seldom attains 

 a length of 400 mm. and the tarsus is almost always less than 70 mm. long. In the New 

 Zealand area there is a larger bird which often lacks the yellow collar and has a tendency 

 towards a duskier plumage, the wing almost always exceeds 400 mm. and the tarsus does 

 not usually fall below 74 mm., but the differences in measurements and still more in 

 plumage are by no means sharply defined between the two groups. 



The specimens from the Crozets, Kerguelen, South Georgia and the South Orkneys 

 are slightly smaller than the New Zealand birds, but the majority of the measurements 

 overlap markedly and on grounds of plumage differences they cannot be separated at all. 



Birds from the South Shetlands appear to fall into two groups, each of which contains 

 darker and lighter forms ; in their measurements the smaller birds resemble the Falkland 

 Islands form, while the larger belong rather to the same group as the New Zealand 

 specimens. 



The skuas of Tristan da Cunha and Gough Island, except for the slightly shorter 

 wing, are comparable to those of South Georgia and should be included with them. 



At the risk of redundancy I would emphasize these two points : 



(1) Plumage differences alone show themselves to be unreliable in separating the 

 four subspecies of Brown Skua recognized by Lowe and Kinnear. 



(2) With the exception of the birds from the Falkland Islands, some from the South 

 Shetlands and one or two odd specimens besides, the measurements of all Brown Skuas 



