Dr. E. Lonnberg on a remarkable Capercaillie. 325 



type. It seems to deserve a separate name, as the aberration 

 is very thorough and at the same time constant. 



If it is asked whether the variation of T. u. lugens can be 

 said to have tended in any certainly definable direction, one 

 might venture to answer atavistic ; for the male T. u. lugens, 

 as it seems, is less highly specialized, than the typical 

 Capercaillie. It has not the beautiful glossy green shield 

 of the latter, its tail is shorter, with narrower, not truncate 

 feathers, and it lacks also the white-marbled band across 

 its middle. The bill is less powerful and the size of the 

 whole bird is smaller. The absence of all white markings in 

 T. u. lugens might perhaps at first tempt us to think 

 of melanism. But on further consideration such an idea 

 must be dismissed, for, with the possible exception of 

 the head and neck, the plumage of this variety contains 

 less melanistic pigment than that of a typical Capercaillie. 

 It is therefore not probable that the absence of white 

 markings in T. u. lugens is due to melanistic agency, in the 

 usual meaning of the word. The white-spotted tail-coverts 

 may, together with the white-marbled band on the tail- 

 feathers, serve for ornamental purpose when the Capercaillie 

 spreads its tail during its " spel" or love-performance. The 

 white spots on these feathers may, therefore, have been 

 acquired as secondary sexual characteristics, aud in such 

 case their absence may be an atavistic feature. The absence 

 of the large white spot on the anterior margin of the 

 wing is, however, much more difficult to explain. This 

 spot may, however, also be an ornament, as it is more 

 strongly developed in fine old cocks than in weaker 

 specimens. 



With the sudden appearance of this T. u. lugens might 

 be compared "the strange case of Athene chiaradiae," 

 described by Giglioli in ' The Ibis ' for January 1903. 

 The latter has also been regarded as a mutation or, as 

 Giglioli terms it, a neogenesis. How far the cases run 

 parallel I am not prepared to say, as I have not been able to 

 compare Athene chiaradia with other Owls. 



At the sixth International Zoological Congress in Bern 



