BTO: Tiny birds who flock together

Long tailed tit'Picture: BTO/Dick Jeeves

Long tailed tit'Picture: BTO/Dick Jeeves

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When it comes to family values we can learn a lot from long-tailed tits, writes Graham Appleton, from the Thetford-based British Trust for Ornithology.

Most birdwatchers have their favourite species but I cannot imagine that anyone would have anything but nice things to say about long-tailed tits.

Whether decorating a pea-nut feeder or building their delicate nests, these are industrious and delightful garden visitors. When you get to know them, they are even more impressive.

Long-tailed tits are tiny, weighing less than 10 grams. Being miniscule is costly in cold conditions so it is really important to keep as warm as possible. As night draws in on a cold, winter evening, long-tailed tits have developed a strategy to cope with the next 16 hours – they huddle together. The first bird in the flock takes up his or her position on a twig and the next bird snuggles close. After that, new arrivals will try to squeeze into the growing line of feathered bundles so as to secure the warmest spot. Often the birds in these flocks are closely related so not only are individuals looking after themselves they are also helping their children, sisters, brothers, parents, aunts and uncles. Come the spring, when flocks break up and pairs establish their breeding territories, a pair needs to create a nest in which their even smaller youngsters can be kept warm. They start building quite early in the season, often spending two weeks collecting moss and weaving it together with spiders’ webs until they have created a ball with a hole in the side. They then cover the nest with grey lichen and find 1,000 or more small feathers to line it. Here’s a species that appreciates the activities of cats and sparrowhawks; one bird’s misfortune creates a pile of suitable lining material with which to make a snug duvet for the eggs and chicks! Building a nest is a huge investment. Once the six to nine tiny, pure white or red-speckled eggs have been laid, the female sits on her brood for a fortnight. If the nest is destroyed early on then the pair may build a replacement but the time invested in creating a home is huge and long-tailed tits give up on the season relatively early on. That’s when family values really come to the fore, as birds without a brood of their own will often help to feed the youngsters of a close relative. Not only does this increase the speed of development of the young, which reduces predation risk, but scientists have shown that adults with helpers are in better condition than those that have to provision chicks on their own.

I have always liked long-tailed tits; they bring life to a garden as they pass through in a twittering flock or gather in a heap on the peanut feeder.