io8 Summer Studies of Birds and Books CHAP. 



space between these two currents is occupied by 

 several other kinds of Yellow Wagtails, all much 

 alike in shape and habits, and for the most part in 

 hue, but differing just in some one point of plumage, 

 and mixing themselves up together in the most 

 delightful confusion, as if to make the men of science 

 pay for classifying them. 1 



The only one of these I shall mention here is the 

 Blue-headed Wagtail of the Continent, the type of 

 its class. A few of these seem to come to us every 

 year ; and just as it is worth while always to look 

 at Pied Wagtails to make sure that they are not 

 White Wagtails, so it is as well to glance at all 

 yellow birds we see, in case we should some day 

 meet with one that has a distinctly bluish head, and 

 a white stripe over the eye instead of a yellow one. 

 A beginner, indeed, may easily confuse the female of 

 the common species for the rarity he is looking out 

 for; and he should never be satisfied until he has 

 watched his bird at a very short distance, and if 

 possible with a good field-glass. Though Oxford is 

 a favourite haunt of Yellow Wagtails, I have in the 

 course of many years detected but two or three of the 

 rarer species. 



1 See Seebohra's British Birds, vol. ii. p. 212 ; Giglioli's 



Avifauna Italica, p. 81. In the Zoologist for November 1892 



is an interesting note by Mr. John Cordeaux on the peculiar 

 migration of this bird. 



