Of course, when it gets frosty outside, we retreat to the cozy living room. But what do tits, blackbirds and robins do to brave the cold?
feather balls and bird’s feet
Tits, finches and sparrows are quite common in the winter bird world. But robins, dunnocks, blackbirds, fieldfares and wrens also stay with us. They all have something in common when it comes to the cold. Birds are warm animals (just like us humans) and therefore need to maintain their body temperature. This is normally between 38 and 42 degrees Celsius. To keep themselves warm, the birds fluff up their feathers until they look like little balls of feathers. This allows them to store warm air between the layers of feathers. They also use their spherical shape to reduce their body surface area, so less heat is lost.
But what about the legs of the birds? After all, these are not covered by feathers. Here the birds use a sophisticated heat exchange system. The blood vessels in the legs are very close together. Therefore, the warm blood just coming from the body can transfer its heat to the cold blood in the feet. This keeps the temperature balanced.
Another trick: Birds can actually sunbathe. Because the dark parts of their plumage absorb about 80 percent of the sun’s heat into their bodies instead of reflecting it. And when the cold gets really extreme, birds can also go into a kind of rigid state. In this state, they shut down their metabolism and thus use less energy.
vegetarians and part-time parents
Some species, such as tits or nuthatches, which feed on insects in summer, have to adjust in winter. During the cold season, they mainly eat seeds, nuts and grains. They contain a lot of fat and are therefore a good source of energy. The berries and fruits that grew on the trees and bushes in autumn are also used now. Some birds (e.g. jays or marsh tits) do like squirrels and set up food stores. Acorns are buried in the ground or seeds are stuck into the cracks in the tree bark. The main thing is that you can find everything again in the end!
When it comes to bird migration, there are not only resident birds and long-distance migrants. Some choose the middle path and only travel short distances to avoid bad weather and sub-zero temperatures. These include, for example, ducks, tits and finches. As a result of global warming, some species are moving ever shorter distances or even become sedentary birds. Quite a few cranes already overwinter in France and save themselves the trip to southern Spain. And black redstarts, blackcaps, song thrushes, chiffchaffs and other migratory birds sometimes don’t set off at all.
Let’s go to town!
In winter, many a bird is attracted to us. Sure, it’s always a few degrees warmer in the city than in the surrounding area, the water doesn’t freeze over so quickly and there’s also food, ducks and blackbirds from the Lang like to come to the cities. On our blog you will also find helpful tips for the right winter feeding.
Cover photo by David Reed on Pixabay
