Sometimes at present a brief, half-whispered song by a bird can be heard coming from the middle of a bush — a hawthorn laden with red berries, or an elder with its leaves changing colour. It is a snatch of sweet trickling sounds, or even a single plaintive note. It is the robins starting to sing again.
The adult robins have been moulting and growing new feathers, and they are always very quiet at that time. But now they are beginning to take up their winter territories, and with these scraps of song they are starting to stake their claims. Meanwhile, the young robins have been exchanging their spotted breasts for bright red ones. They learnt what a robin’s song should sound like in the weeks after they hatched, when their father was still singing. They have not used that newly-acquired knowledge until now. But with their new adult plumage the urge comes on each of them to take up a territory for itself — and as they prepare for that they are now singing for the first time in their lives.
In fact the young robins often start trying to get a territory before their parents have finished moulting, frequently bidding for a portion of their parents’ summer territory. The female robins want a winter territory of their own too. So war is on the way in the robins’ world. As September goes on, the songs of all the robins will get stronger and louder as they challenge each other. The female may manage to go halves over possession with her summer mate, but the young birds vigorously assert their right to a place in the world, and the month can see fierce fighting, even deaths.
Eventually the situation will settle down. The birds will all go on singing to defend their new territories from trespassers, but it will be a quieter scene. We are lucky that robins hold winter territories, since there is not a lot of bird song except theirs to listen to between now and Christmas. After that, the males’ song will get even sweeter and richer, as they call out for a mate to join them, and the cycle of the year begins again.