Plumage of the Mountain Chat. 35 



Mr. W. L. Sclater, in the second volume of the Birds of 

 the 'Fauna of 8. Africa' series, apparently agrees with 

 Messrs. Butler, Feilden, and Reid, hut gives only seven 

 stages of plumage. 



Since October 1909, I have, in the district of Matatiele, 

 E. Griqualand, where the Mountain Chat is fairly common, 

 devoted a good deal of my time to observing and collecting 

 specimens of this species. As the result of my observations, 

 and thinking carefully over the matter, I have come to the 

 conclusion that Mr. Seebohm's theory is the nearest to the 

 truth. 



Although being unable to disprove the theory of Messrs. 

 l)utler, Feilden, and Reid, I am not inclined to agree with 

 with it, as some of my observations do not altogether agree 

 with theirs. 



My own theory is a modification of Mr. Seebohm's, but 

 with this ditference, that instead of there being tw^o species, 

 that there is only one^ which is dimorphous, i. e., having two 

 formSj a black and a grey one, and that all the intermediate 

 plumages betw^een the two extremes may be caused through 

 the interbreedino- of the two. I do not consider the fact that 

 the females do not vary much in colour to be against my 

 theory, as it is well known that among many nearly allied 

 sj)ecies of birds, of which the males differ very much from 

 one another, the females are almost indistinguishable (a case 

 in point is Pyronielana orLc and P. taJia). 



Now I think that if it was the case that the males of 

 S. moiiticola changed gradually through a regular sequence 

 of plumiiges from black to grey, the birds in the plumage 

 intermediate between the two extremes would be as common 

 as the latter, whereas 1 have found this far from being the 

 case ; in fact, that while I could have secured a large 

 number of both black and grey birds, I have had con- 

 siderable ditficulty in getting specimens in intermediate 

 plumages. 



Messrs. Butler, Feilden, and Reid give as one of the 

 reasons for believing the grey birds to be the oldest is their 

 scarcity ; but I have found this form, if not the commonest, 



