FALCO CANDICANS, J. f. Gmei. 
Greenland Falcon, dark race. 
The birds figured on the two accompanying Plates differ from both the white or true Falco candicans and 
the F. islandus, and moreover are so inconstant in their markings that I have never seen two specimens 
that had the tail similarly marked ; for while the barrings of the feathers are perfect in one, in another they 
are interrupted. In one the second and third feathers from the middle ones may be wholly white ; in another 
the same feathers may be more or less barred. A degree of inconstancy also occurs in the markings of 
the back and wings, although generally to a less extent ; but the young of the year of the white F. candicans 
and the young of this dark race assimilate In being lightly coloured, in which respect they offer a decided 
contrast to the young of Falco gyrfalco and F. islandus, which at the same period of their existence are 
both dark. By some persons it may be supposed that the individuals of the dark race change their 
plumage as they advance in age, and ultimately become white ; but if the assertion of those ornithologists 
who have paid special attention to these Falcons, that the plumage they assume at their second moult is 
carried throughout life, he correct, this will not be the case ; and that this theory is the true one would seem 
to be confirmed by the fact that a Greenland Falcon which lived for some years in the Gardens of the 
Zoological Society never exhibited any subsequent change. Professor Newton states that the true 
Icelander is believed to breed in the southern parts of Greenland. If this Is the case, it appears to me 
probable that this dark or mongrel race may be due to the interbreeding of F. islandus and F. candicans, 
in which event the progeny would naturally be intermediate in colour and markings. As an instance in 
point I may cite the results of a cross between our two species of Pheasants {Phasianus colchicus and 
P. torquatus), the progeny of which not only differ in their plumage from the parent stocks, but even as 
compared with one another. If this is not the cause of the abnormal state of plumage of these Falcons, 
I am at a loss to account for it. I may mention that these strongly marked birds appear to be more 
exclusively natives of South Greenland, and that It is from the Danish settlements in that country that 
specimens are sent to Europe. It is the young of these indistinctly marked birds that most frequently visit 
Britain, of which Lord Cawdor’s specimen, now in the British Museum, is an example, and is represented in 
the second figure, or young of the dark race, in the accompanying Plate. 
Whether these noble Falcons have all sprung from one stock is a question not easily answered ; neither is it 
easy to say, in that case, which most approximates to the common progenitor; but we may, I think, 
fairly conclude that it must have been the Falco candicans in its whitest and purest state, inasmuch as it Is the 
bird which inhabits the highest northern regions, or the icebound portions of the arctic zone. Geologists will 
tell us that, in ages gone by, Iceland and Northern Europe were in the same state, and that glaciers, instead 
of the peaty morasses which now exist, then prevailed. May not the physical changes that have taken place 
in more recent periods have had an influence on the colouring of these Falcons ? That such a change has 
been effected In the case of the common Grouse {Lagogus scoticus) I feel assured, inasmuch as I find no 
difference, except that of colour, between it and the white Lagopus saliceti of Norway and America. To 
assert positively that the milder atmosphere of our more humid sea-girt islands, and their more peaty and 
heathery soil, is the cause of the difference in colour between the two birds, would perhaps be speaking too 
strongly ; yet I think it probable that such a theory would be the right one. 
Those who have studied the birds of the world in their entirety must have been struck with the fact 
that, while certain forms are abundant in one portion of the globe, they are totally absent from the opposite 
one. For instance. In the northern or arctic hemisphere Auks, Puffins, and Guillemots abound, while none 
of these forms are to be found in the opposite or southern hemisphere, their place there being occupied by 
Penguins and Albatrosses. This is not easily to he accounted for, since, on the other hand. Cormorants 
haunt the sea-girt rocks of every part of the globe, and Gulls and Terns are no less universally dispersed. 
This absence of certain forms, again, from countries not very far distant from those in which sucli forms are 
numerous is further exemplified in the fact that, while there are neither Swallows nor Crows in New Zealand, 
Norfolk Island, or perhaps the whole of Polynesia, Swallows, Martins, and Swifts are abundant in Australia, 
and Crows are as numerous there as in any other country — all, however, being specifically different from the 
birds thus called which inhabit the same latitudes in the northern hemisphere. Were it necessary, other 
instances of this apparent limitation of species in certain parts of the globe might be cited almost ad 
injinitum ; and we might theorize to a similar extent as to why a Crow should not inhabit New Zealand as 
well as Australia, or why Swallows should be plentiful in the one country and not in the other. The 
