175 
THE MIGRATION OF THE YELLOW WAGTAIL. 
BB We LOCK, 
Beeston, Notts. 
I sHOULD just like to add a few final words to this discussion, as 
Mr. Cordeaux in his latest contribution somewhat shifts his ground, 
and also attempts to saddle me with his own theory as to the origin 
of these flights of Yellow Wagtails. He writes—‘There is no 
necessity for Mr. Whitlock to bring the main colony of M. rati 
from their summer home on the Lower Volga and basin of the 
does himself in his ‘Zoologist’ paper, and is the very point I tried to 
refute. His latest suggestion that occasional flights come over from 
Holland and Belgium is far more probable, but he forgets that in 
the first instance he described the migration as xormad. 
When considering the movement of a single species, one naturally 
takes a more narrow view of migration ; but to argue that because st 
Bluethroat, with which the Yellow Wagtail has very little in commo 
may cross a large tract of country without being seen, that eaoen 
the present species in like manner might escape observation en route, 
is almost certain to lead to error. It is well known that birds in 
different parts of their ranges have different habits. ake the 
Dotterel (Zudromias morinellus) for instance. This species is stated 
y Mr. Seebohm to probably cross the whole of Europe to its 
northern breeding grounds in a single flight. Now in our own 
country it is observed in many districts resting, in small flocks, 
before travelling further north, for several days at a stretch. The 
same is probably true of the Bluethroat in other regions.* The 
Yellow Wagtail, too, unlike the Bluethroat, is regularly observed on 
migration on the east coast of Spain, thus plainly showing that it 
migrates more leisurely than the former r species. Indeed, it has 
only half the journey to perform. Mr. Caton Haigh suggests that 
M. raii probably travels by night; this may be true to a certain 
extent, but his own note of flocks coming in from the east a// day 
rather militates against this opinion. 
With regard to my not finding large flocks of AZ. rat near 
Skegness in September 1891, I argued nothing from this, as 
I considered I was a little too south of the probable track, and if 
Mr. Cordeaux will refer to my paper again, he will see that I merely 
mentioned the matter in passing. 
* The . Rinesianuk' as care to come in EEE a to a certain an 
of Baden. As the writer does not state that they breed there I presume he refers 
to the Arctic form, on migration (Douglas, Zoologist, p. 168, vol. xviii). 
June 1 Bo. 
