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Correspondence.



and flowers, and snapping yonng twigs by its weight, than it does

good by the destruction of an occasional green-fly. Moreover, the

Sparrow breeds nearly all the year round, even in mild winters.

I remember that as a boy I liked it very much, with a bit of steak,

in a pie; but otherwise I shall always regard it as a public nuisance.

—Yours very sincerely,


A. G. Butler.



Dear Dr. Renshaw,- —With reference to Dr. Butler’s opinion

as to birds feeding upon tbe larvae of the Magpie Moth (Abraxas

grossulariata ), I regret that I am unable to agree with him. Firstly,

because I have taken them on numerous occasions from the stomachs

of the Blackbird, Song and Mistle Thrush, Blue and Great Tits,

Whitethroat, Chaffinch, and other species. Secondly, in the spring

of 1918 a most interesting case came under my notice, which was very

carefully inquired into. Some currant bushes were noticed to be

very badly infected with the young larvae of the Magpie Moth, and

for the first four or five days after they appeared they attracted quite

a number of Song and Mistle Thrushes, which were observed feeding

upon the caterpillars. Over a hundred were found in the stomach of

a Song Thrush, and fifty to sixty were common in some of the Mistle

Thrushes examined. Suddenly the birds ceased to feed upon the

larvae. On examining the bushes many larvae were found to remain.

Some were collected (forty-one examples) and kept. From these

I reared fourteen masses of cocoons of Microgaster and twenty-seven

specimens of Exorista. Not one of the larvae entered upon the pupa

stage. Further, after most careful searching, not a single pupa could

be found beneath the bushes, and we have scarcely seen a moth,

although there must have been tens of thousands of the larvae.


Here, I think, we have an excellent example of two natural

agencies, viz. wild birds and insect parasites, practically controlling

what would otherwise have developed into a serious plague.


These larvae may not be eaten to the same extent as those of

other common species, but it is certainly a mistaken impression that

they are entirely avoided by wild birds in their free condition.



