On a mild day last week I was rather surprised to see a brimstone fly past and a couple of swallows pass overhead. Surely, it was time for the former to be hibernating and the latter to be heading for South Africa? In fact, it is not particularly late to be seeing either species, but I have not seen them locally for some time. I was more surprised to hear a blackbird singing. It took a few seconds to register what it was, by which time it had stopped. There is a fair bit of birdsong at the moment, mainly from robins, great tits and wrens. The idea used to be that the shrinking hours of daylight fooled the birds into thinking it is spring. This never appealed to me and a better explanation is that these birds set up territories, and sing in their defence, after the summer moult. They later abandon the territories when (and, nowadays in the south, if) the weather deteriorates and they are forced to wander in search of food. It has been a puzzle to me that one does not usually hear blackbirds in autumn. They normally start singing in February, or may be January if the weather is mild, and fall silent when breeding has finished. This is despite the fact that they re-occupy their territories after the moult and maintain them through much of the winter. The answer to the puzzle seems to be that blackbirds do not use song much for territorial defence, except for young blackbirds when they are trying to establish themselves. I did not see this blackbird but I bet it was a young male trying to take its mark in society.
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