of his full song—in fact, his autumn song is nothing more than a very subdued warble, so low that it cannot be heard beyond a few yards' distance, and kept up almost continuously whilst he creeps about amongst the bushes. The duration of this autumn singing appears to depend very much on the weather; in the case of the Chiffchaff and Willow-Wren it usually begins with August, and lasts until early in September; but in the phenomenally hot autumn of 1897 the Willow-Wren was singing every day in the south of Yorkshire up to the 30th of September, and the Chiffchaff up to the 3rd of October; whilst in the mild winter which followed, both Chaffinch and Yellowhammer were singing occasionally until well on in December; and both were, once more in song before the end of the following January—the Chaffinch for the first time on January 21st, the Yellowhammer on the 25th.
