24 THE ZOOLOGIST. 



Differences between immature Blue-headed and ordinary Yellow 



Wagtails. — Can any reader give some definite characteristics to dis- 

 tinguish immature birds of the Blue-headed Wagtail (Motacilla flava) 

 from those of the ordinary Yellow Wagtail (M. campestris) ? Mr. 

 Howard Saunders, in his ' Manual,' apparently regards the white eye- 

 stripe as the distinguishing feature of M. flava. Dr. Bowdler Sharpe 

 describes this eye-stripe as " tawny buff," and winds up with the 

 statement that "young birds of M. flava are scarcely distinguishable 

 from those of M. campestris." During the last three autumnal migra- 

 tions I have paid considerable attention to the point, and it would be 

 interesting to see if the experience of others in any way coincides with 

 my own. In September, 1899, I was looking out for M. flava amongst 

 some flocks of M. campestris on the Norfolk coast. I scrutinized these 

 flocks daily through strong glasses, and at last encountered a bird 

 which struck me at once as being different to the ordinary run. Seen 

 at a distance, it appeared darker above, especially about the head. I 

 shot it and set it up, and may mention that a good judge, who saw it, 

 momentarily took it for a Grey Wagtail. I showed it afterwards to 

 Mr. J. H. Gurney and Mr. Southwell at Norwich, both of whom agreed 

 that it was a specimen of M. flava. The eye-stripe was light tawny 

 buff, and the throat white ; the upper parts of the head and back dark 

 greenish grey, not brownish. Against this darker ground the light 

 margins of the wing-coverts and tertiaries showed up more than in 

 M. campestris. In September, 1900, I was at Aldeburgh, and Yellow 

 Wagtails were abundant on Thorpe Mere. I shot one or two to com- 

 pare with my Norfolk bird, but once only saw anything to remind me 

 of it ; and this bird I failed to secure. Last year I was again in 

 Norfolk, and came across a Wagtail which, as it ran, reminded me of 

 the 1899 bird. I shot it, and have since compared the two. The later 

 one agrees exactly in the hue of its upper parts and dark head ; the 

 eye- stripe is ill-defined but light, while the throat, though light, is 

 certainly not so white as in the former bird, but has a yellowish tinge, 

 especially at the sides. Still, comparing them with my Yellow Wag- 

 tail, I believe that they are both specimens of M. flava, and would 

 suggest that the real difference between the two species at this age 

 lies in the different hue of the upper parts, especially the head. The 

 natural fading of a stuffed bird will doubtless soon reduce both eye- 

 stripe and throat to white, and I cannot help thinking that these dis- 

 tinctive marks have in consequence been overrated, and that M . flava 

 is a commoner bird in autumn than has been supposed ; but that, as 

 in the case of the Marsh- Warbler, an eye to variation in the shade of 

 colour is the main requisite for its detection. In the Pied Wagtail 



