If you’ve wrapped up warm and been on a winter walk recently, passing through woodland or along a hedgerow, at some point along the way you are likely to have found yourself suddenly surrounded by gentle chirps and whistles and may have caught sight of a flurry of movement high in the branches; you will have stumbled into the middle of a tit flock. Blue Tits, Great Tits, Long-tailed Tits, Coal Tits as well as Goldcrests and Chaffinches are often found together at this time of year.
During summer small song birds are very territorial, defending their local patch as they work hard to raise their chicks. By contrast, in winter most small birds ditch this behaviour, instead favouring a much more sociable approach, spending their days in mixed species groups, some of which can get quite large. So why the change? In summer the birds are competing with one another for mates and enough food to feed their young. However, in the colder months, other factors become more important. By sticking together, they improve their chance of survival; more eyes improves their chances of finding food as well as detecting predators such as Sparrowhawks before it’s too late.
Huddling together during the critical night-time period also helps conserve body heat; Blue and Great tits have been shown to loose 5% of their body weight between dusk and dawn. Energy-wise, a Blue Tit (weighing about 11g) needs 1kcal per gram of body weight each day during winter. This is equivalent to consuming some 300 small insects weighing about 10g in total! It is therefore not surprising that they can spend around 85% of the daylight hours foraging for food and thus any foraging benefits gained from flocking with others can be significant. Just another reason why keeping bird feeders topped up at this time of year is so important.
Interestingly within winter foraging flocks the different species show marked differences in height of foraging and/or species of tree frequented. For example Great Tits and Coal Tits favour the inner parts of branches, Blue Tits and Marsh Tits are usually found on the outer sections of branches and Long-tailed Tits and Goldcrests on the twigs thereby minimising competition through niche specialisation.
Elsewhere around the parish, small mammals such as shews, voles and mice have also been struggling to find enough food to survive the recent cold nights and several exciting birds species have been recorded – a woodcock was spotted flying over Castle street and 14 Woodlark were observed in a field between Aldbourne and Ramsbury – the biggest flock of Woodlark ever recorded in Wiltshire!
Check out the wildlife sightings page on the website to keep up-to-date with our local wildlife and please do keep reporting what you see, it’s great to hear what’s around.