Nature Notes for 21st September, 2017

Jenny Dixon

Wharfedale Naturalists Society

It’s quiet around the bird feeders, just jackdaws demolishing my expensive fat-balls. Other familiar characters are off in the woods foraging the rich supplies of wild fruits and invertebrates. Then – if I’m looking out at the right time – bonanza! A flock of small birds, blue, great, coal and long-tailed tits, comes swooping in and everything is flickering with action. It’s a chance to hone my identification skills – not just plumage patterns – that’s easy – but recognition of characteristic behaviour: coal tits darting in, seizing a seed and retiring to cover, great tits assuming the rights of the biggest and sitting tight, blue tits showing off their agility , nipping in at every opportunity and nonchalantly hanging upside down, and the long-tails flitting, shimmering, briefly turning the fat-balls into a many-tailed feather globe. Then – just as suddenly – it’s over. This is the pattern for end of summer – families coalescing into many-eyed, cooperating flocks.

Several friends have told me how their house martins have vanished from nesting sites and a few lucky ones have been enjoying watching and listening to the huge pre-migration gatherings of these hardy little birds. I remember watching them in great numbers skimming a field in the Lake District. Low pressure had brought the flying insects low over the grass and they swooped and swerved in pursuit keeping up a wonderfully cheerful twittering as they went: feeding up for the great journey. It’s crucial to get the balance right, no excess weight but enough energy to sustain the flight. The excited chatter as they feed or just perch sociably on high wires presumably establishes a useful connectedness for the mass exodus. And then, suddenly, some signal – weather, wind direction, temperature change - triggers instinct and they’re gone – till next year.

All this is fairly familiar but then – a surprise. A friend tells me that on a sunny morning’s golf last week he heard chiffchaffs singing from the edge of the woods. A few hardy chiffchaff now over-winter here but most migrate to Africa. We are taught that birds sing to maintain territory or attract a mate. – neither a priority now. A knowledgeable friend looked it up in the ornithologists’ bible, Birds of the Western Palearctic – 9 volumes of accumulated wisdom. One sentence acknowledged - male chiffchaffs sing in the moult and into Autumn. Strict science doesn’t tackle the “why?” Are youngsters finding their voices or perhaps they’re all establishing community links before the great journey. A mystery!

Meanwhile garden robins are in full song here – staking their claims to winter territories.