THE ZOOLOGIST 
No. 804.—June, 1908. 
NOTES ON THE OYSTERCATCHER (HAIMATOPUS 
OSTRALEGUS), WITH REFERENCE TO ITS 
HABIT OF FEEDING UPON THE MUSSEL 
(MYTILUS EDULIS). 
By J. M. Dewar. 
To say that the Oystercatcher eats Mussels is to assert a 
commonplace. Yet little seems to be known regarding the 
methods by which the shells are opened and are deprived of 
their contents. Apart from the question of expediency, the 
absence of information on this subject may be attributed to the 
difficulties inseparable from close observation of birds that are 
wary and not easy to approach. Oystercatchers avoid those 
places which permit an observer to approach unseen, they act 
with great rapidity, their methods are varied within wide limits, 
and it is only by the exercise of much patience that results of 
any value are obtained. The present account is based partly on 
observations of the birds themselves, and partly on an examina- 
tion of the empty shells which are scattered over the feeding- 
places. 
Oystercatchers are creatures of regular habit; their time- 
table is regulated by the ebb and flow of the tides, which they 
follow with more or less precision. Speaking generally, it may 
be said that the Mussel-scalps extend across the shore from a 
line distant about one hour from the high-water mark to a line 
corresponding with the low-water mark of neap tides. The 
Zool. 4th ser. vol. XII., June, 1908. R 
