Birds occupy even the coldest parts of the world, and so it's only natural to wonder how they survive when the mercury drops. Birds do not hibernate in the way bears and ground squirrels do. They employ a number of strategies to survive the cold, or simply escape by migrating to warmer climates for the winter.
Birds do not hibernate, but some species do enter torpor. Torpor is similar to hibernation but does not last as long, ranging from several hours to several days. Hummingbirds, for example, are known to enter a torpid state to survive cold nights, while common poorwills can enter this state for even longer periods.
Birds are highly mobile creatures. They are able to travel further and faster than the other animals they share their habitats with. This allows them to simply fly south to avoid the harsh days of winter. Nevertheless, there are several species that are adapted to tough it out and brave the cold with some clever behavioral and physiological adaptations.
Read on to learn more about hibernation and birds.
Hummingbirds are amongst the species of birds which enter torpor
Birds do not hibernate, but many species can enter a state of torpor. Torpor is much like hibernation but lasts for shorter periods of time.
One fascinating nocturnal bird can enter a state that is very close to hibernation. The common poorwill (Phalaenoptilus nuttallii), a superbly camouflaged bird of the Caprimulgidae family, can enter a state of torpor lasting several weeks.
These nocturnal birds of the American Southwest can allow their body temperature to drop to as low as 41 degrees Fahrenheit (5°C) when in torpor, and spend as much as 90% of the cold winter days in an inactive state.
Some species from the following bird groups also have the ability to enter torpor:
Common Poorwills can enter torpor for weeks
Torpor is a survival strategy that some birds use in cold weather. Birds typically maintain relatively high body temperatures of between 101 and 111 degrees Fahrenheit, but staying so warm when the ambient temperature gets very low uses a lot of energy, especially for small birds.
Trying to maintain their body temperature can be a losing battle, and the consequences of running out of energy are fatal. Amazingly, some birds are able to slow their heart rate and breathing and allow their body temperature to drop severely in order to save energy.
This is a risky move in itself because coming out of torpor isn’t like waking from regular sleep. It can take some time, and since warming up requires energy, this strategy is better suited to areas where temperatures increase markedly when the sun rises.
Mousebirds also go into torpor
Many birds survive cold winters by avoiding them altogether! Bird migration to warmer climates is a very common and impressive survival strategy that allows birds to avoid cold and the lack of food resources that go hand in hand with cold winters. Those species that choose to tough it out make use of various behavioral and physiological adaptations to see them through those cold, short days.
Most birds cannot survive without eating for long periods of time, so those that stay put in areas with cold winters can only do so where food is available throughout the year. Some clever birds like chickadees actually store food for the winter. This behavior is known as caching and it is also seen in other birds like nuthatches and crows.
Birds keep warm in many ways, such as packing on body fat, sheltering from cold winds, fluffing out their feathers, and even huddling together at night. Feathers are an excellent source of insulation from cold, so birds often cover their legs and tuck in their bills to avoid heat loss.
Chickadees cache their food for the winter
Birds shiver to keep warm, much like humans and other mammals do. Their technique is a little different, however. By contracting opposing muscle groups birds are able to generate warmth.
If a bird is not able to find enough food or find shelter from cold weather, it could certainly die from hypothermia. This could happen to old, sick, or injured individuals, or be the result of unusually cold or stormy weather.
Pet birds that are adapted to survive in warm climates are also at risk of suffering in cold weather. They will use behavioral strategies like puffing out their feathers to stay warm, but they do not have the adaptations that native birds have for surviving low temperatures.
Female European Stonechat in the winter
Staying hydrated can be a big challenge for birds in winter. As if staying warm and finding enough food wasn’t tough enough, birds also have to cope with water sources freezing over when the mercury drops.
Birds use a number of clever ways to drink water during winter. They will take in ice, snow, or even catch falling snowflakes! When warm enough, they will drink the droplets that drip off of icicles. Birds also get some of the water they need from their food, although this is usually not enough to keep them fully hydrated.
An American Robin drinking water from a puddle in winter
Bird feeding is a very popular activity across the world, and the birds enjoy it as much as we do! Of course, birds do not actually need any help to survive, and they have existed for millions of years without any assistance at all. Birds will, of course, be more than willing to accept your help.
You can help birds in winter by providing energy-rich food sources like sunflower seeds, peanuts, and suet. Remember, hygiene is very important to avoid spreading disease, so keep those feeders clean and only use fresh food. Keeping a supply of unfrozen fresh water available will also allow the birds to drink and bathe when all the other water around has frozen, just be sure to clean your bird bath regularly.
Growing native plant species that produce fruits and berries in the winter is another wonderful way to help birds during those cold days. A well-planted yard with some evergreen trees and bushes will also provide birds with places where they can shelter from snow and cold winds.
Feeding birds in the winter is essential and really helps with their survival
The species of birds that are commonly kept as pets do not enter hibernation. Most pet birds originate from tropical, subtropical, and relatively mild climates. It is important to keep them in a warm environment if you experience cold winters.
Lovebirds originate from subtropical Africa where winter temperatures are mild to warm. They do not hibernate.
Hummingbirds do not hibernate but they are famously able to enter a state of torpor to survive cold nights. In this state, hummingbirds allow their body temperature to drop to near ambient levels, and their breathing and heart rate slow dramatically.
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