THE EVOLUTIONS OF WADERS. 167 
movements gradually become less prolonged, less elaborate, and 
eventually are not aroused. When high-water comes late in the 
winter’s afternoon the Waders return in the dusk over the same 
course as that taken before high-water. They come back sedately 
in low flying strings, in marked contrast to the generally pro- 
longed displays which they give at the earlier time. On the 
return journey the dim light increases the Waders’ margin of 
safety to the extent of absolute security. As the winter ad- 
vances, the evolutions become of almost daily occurrence from 
half-tide onwards, until the Waders leave for the refuge, and 
when high-water occurs early in the day they delay beyond the 
usual time their return with the ebb, so that a landing may be 
effected on the foreshore out of range. Some of these observa- 
tions show that the danger need not actually be present. It is 
sufficient that the memory of a past danger should be fresh, 
that a place or period should be ‘“‘notoriously dangerous.”’ 
If the view be accepted that the evolutions have been evolved 
for a defensive purpose, and that the essential form of movement 
is an imitation of the sea-spray, it is tantamount to saying that 
the evolutions of Waders are an example of Protective Resemblance 
within the literal meaning of the words, though I doubt if any 
definition that has ever been propounded for Resemblance covers 
the present instance. Resemblance to the intermittent motion 
of an inanimate object has not, as far as I am aware, been 
hitherto described, and I have no evidence leading me to believe 
that deception is practised or intended (unconsciously as by 
general consent it is assumed to be). On the other hand, there 
are some reasons for believing that the object is to baffle pursuit 
or attack. Ihave not seen a predaceous bird which suggested 
by its actions any doubt it may have had as to the nature of a 
flock of Waders. The hawks, in particular, attacked the Waders 
at sight, and on two occasions were seen to steer a course from 
a distance directly and without hesitation towards Waders 
engaged in evolutions. At the same time the close packing of 
the flock, the rapid and apparently purposeless movements in 
unexpected directions bring home to pursuers the relative in- 
vincibility of the device. 
In Britain the principal enemies with whom the smaller 
Waders have to contend are man, diurnal birds of prey, crows, 
