SAND MARTIN. 73 
county. The birds commence to flock at the end of 
July, and leave gradually during August and Sep- 
tember, although in some years a few may be met 
with as late as the middle of October. 
In August, Sand Martins congregate in vast flocks 
in different parts of the Mersey Valley between Stock- 
port and Warrington, and we have seen them lining 
the telegraph wires in thousands or hawking for insects 
over the low-lying meadows. Describing one of these 
flocks which he observed in 1893, near Wythenshawe, 
Mr. J. J. Cash writes:—‘On August 12th, the neigh- 
bourhood was inundated with Sand Martins. I never 
saw so many before. The air was full of beating wings 
and clamorous twitterings. The birds covered a wire 
railing a hundred yards or more in length, until it 
resembled a thick cable without a flaw. Their heads 
were all in one direction, pointing to the west. The 
surrounding trees were filled, and the birds flew in and 
out amongst the foliage of one large chestnut like bees 
around a hive. They must have numbered incalcul- 
able thousands, and the district in question evidently 
was for some reason, in 1898, the rendezvous for 
Martins over a very wide area. The flock haunted the 
district for ten days. A foretaste of autumn at the 
end of July no doubt precipitated the assembling, but 
the return of intense heat in August evidently checked 
the departure. However, on the bank of the Mersey, 
near Sale, on the evening of the 22nd of the month, I 
saw what I took to be the same concourse again—for 
surely two such multitudes could not exist in close 
proximity! The whole expanse of sky was speckled 
and dotted with birds flying at a great altitude, and 
bearing slowly but surely westward, the direction 
Swallows and Martins invariably take when leaving 
