How Do Wild Birds Keep Warm In Winter?

Many backyard birders are astonished at the wide variety of winter birds that visit their feeders even on the coldest days, and they may wonder “how do wild birds keep warm in winter?” Birds have many superb adaptations that allow them to survive even in the most frigid conditions, and birders who understand what birds need to keep warm can easily help their feathered friends.
Birds are warm-blooded animals that have a much higher metabolism, and thus higher body temperature, than humans. While the exact measurement varies for different bird species, the average bird’s body temperature is 105 degrees Fahrenheit (40 degrees Celsius). Body temperature can fluctuate during the day depending on climate and activity, but it can be a challenge for birds to maintain such a high body heat when temperatures dip too severely. Smaller birds are particularly at risk, since they have a proportionally larger surface area on their bodies to lose heat but a smaller core volume to generate it. Even the smallest birds, however, have several ways they can efficiently keep warm.
What Wild Birds Do to Keep Warm
Birds have many physical and behavioral adaptations to keep warm, no matter what the low temperatures of their surroundings.
Physical Adaptations
Feathers: Birds’ feathers provide remarkable insulation against the cold, and many bird species grow extra feathers as part of a late fall molt to give them thicker protection in the winter. The oil that coats birds’ feathers also provides insulation as well as waterproofing.
Legs and Feet: Birds’ legs and feet are covered with specialized scales that minimize heat loss. Birds can also control the temperature of their legs and feet separately from their bodies by constricting blood flow to their extremities, thereby reducing heat loss even further.
Fat Reserves: Even small birds can build up fat reserves to serve as insulation and extra energy for generating body heat. Many birds will gorge during the fall when food sources are abundant, giving them an extra fatty layer before winter arrives.
Behavioral Adaptations

Fluffing: Birds will fluff out their feathers to create air pockets for additional insulation in cold temperatures.
Tucking: It is not unusual to see a bird standing on one leg or crouched to cover both legs with its feathers to shield them from the cold. Birds can also tuck their bills into their shoulder feathers for protection.
Sunning: On sunny winter days, many birds will take advantage of solar heat by turning their backs to the sun (therefore exposing the largest surface of their bodies to the heat) and raising their feathers slightly. This allows the sun to heat the skin and feathers more efficiently. Wings may also be drooped or spread while sunning, and the tail may be spread as well.
Shivering: Birds will shiver to raise their metabolic rate and generate more body heat as a short term solution to extreme cold. While shivering does require more calories, it is an effective way to stay warm.
Roosting: Many small birds, including bluebirds, chickadees and titmice, will gather in large flocks at night and crowd together in a small, tight space to share body heat. They can roost in shrubbery or trees, and empty birdhouses and bird roost boxes are also popular locations to conserve heat. Even individual birds choose roost spots that may have residual heat from the day’s sunlight, such as close to the trunk of a tree or near any dark surface.
Torpor
Many birds will enter torpor to conserve energy during cold winter nights. Torpor is a state of reduced metabolism when the body temperature is lowered, therefore requiring fewer calories to maintain the proper heat. Most birds can lower their body temperature by a few degrees, but torpid birds have lowered their body temperatures by as much as 50 degrees. Torpor can be a dangerous behavior, however, as the reduced temperature also leads to reduced reactions and greater vulnerability to predators. Hummingbirds, chickadees, swifts and other types of birds regularly use torpor as a way to survive cold temperatures.
Helping Keep Birds Warm
Even with all these adaptations to conserve heat and stay warm, many birds still succumb to frigid temperatures and bird mortality can be very high during severe winters. Birders who know how to keep wild birds warm in winter can help their backyard flocks have an edge over the cruelest weather.
Offer Good Food: Choosing the best winter bird foods to offer means selecting seeds, suet, scraps and other items high in fat and calories to give birds plenty of energy to generate sufficient body heat.
Keep Feeders Full: After a long, cold night birds will need ready access to food to replenish their energy reserves. Keep your birdfeeders full of nutritious seed no matter what the weather so the birds know where to go for a high energy meal.
Offer Liquid Water: Birds can melt snow to drink if necessary, but doing so will use precious energy that is needed to maintain body heat. If the birds can drink from a liquid birdbath even in freezing temperatures, they will have a better chance at survival.
Provide Shelter: Plant evergreen shrubs and coniferous trees that will provide suitable shelter throughout the winter, or build a brush pile to give birds a safe, sheltered place to roost. Adding a roost box to your yard is also helpful.
When temperatures start to dip, it isn’t necessary to worry about how birds keep warm; they have plenty of efficient adaptations to survive even the chilliest nights. Birders who understand those adaptations and help birds with even better food, shelter and other necessities, however, will be sure to enjoy warm and healthy winter backyard birds no matter how cold it is outside.
Please contact Kennedy Wild Bird Foods if you have any questions about feeding wild birds this winter.

Winter Wild Bird Care

In recent years, there has been a huge growth of interest in feeding garden birds in the UK. This makes a significant contribution to the annual food requirements of many bird populations. At a time when human changes to the environment are a major threat to many other species, garden bird feeding has never been more important.
It used to be that animals were either kept, and therefore our responsibility, or wild, and not. But now it is not so simple. Because of the size of the human population and the extent to which we use or control the environment, we greatly, and often directly, influence the welfare and fates of very many wild animals. This has brought increasing responsibility for them. Human/garden bird interactions are one of the front lines in the development of this new relationship with wildlife. Having taken over a large proportion of the land for housing, industry and farming, providing food for wild birds is one way of helping to redress the balance.

Bird Feeding

Providing birds with food will bring them closer for you to marvel at their varieties, fascinating behaviour and wonderful colours. Feeding birds is also an ideal way to enthuse children about wildlife. This supplementary feeding can't provide all the natural proteins and vitamins that adult and young birds need, so it's important to create and manage your garden to provide a source of natural foods as well, through well-managed lawns, shrubs and flowerbeds. If you provide both natural and supplementary food, your garden will be turned into a wildlife haven and will be visited year-round by a host of different birds. It is important to feed your garden birds responsibly and safely. By following a few simple guidelines, you can play a valuable role in helping your local birds overcome periods of natural food shortage, survive periods of severe winter weather and come into good breeding condition in the spring.

Bird Food

There are a variety of different types of bird food available to buy. Here is a guide to what to feed your garden birds and when.

Bird Seed Mixtures

There are different mixes for feeders and for bird tables and ground feeding. The best mixtures contain plenty of flaked maize, sunflower seeds, and peanut granules. Small seeds, such as millet, attract mostly house sparrows, dunnocks, finches, reed buntings and collared doves, while flaked maize is taken readily by blackbirds. Tits and greenfinches favour peanuts and sunflower seeds. Some seed mixes now contain added suet pellets, fruit or pieces of mealworm. Mixes that contain chunks or whole nuts are suitable for winter feeding only. Pinhead oatmeal is excellent for many birds. Wheat and barley grains are often included in seed mixtures, but they are really only suitable for pigeons, doves and pheasants - which feed on the ground and rapidly increase in numbers, frequently deterring the smaller species. Avoid seed mixtures that have split peas, beans, dried rice or lentils as again only the large species can eat them dry. These are added to some cheaper seed mixes to bulk them up. Any mixture containing green or pink lumps should also be avoided as these are dog biscuit, which can only be eaten when soaked.

Black Sunflower Seeds

Also known as black oil seeds, these are an excellent, economical all-year-round food; rich in energy-giving oils and protein, and in many areas are even more popular than peanuts. The oil content is higher in black than striped ones, and so they are much better. Black sunflower seeds are an excellent food source as almost all wild birds that visit your garden will readily eat them. The husk of the black sunflower seed is thin, so it can be easily broken by wild birds, even those with small beaks. They are also versatile and can be fed using seed feeders, a bird table or on the ground. Black sunflower seeds are eaten by the following wild bird species: blue tits, blackbirds, bullfinches, chaffinches, coal tits, goldfinches, great tits, green finches, sparrows, siskins, nuthatches, robins, song thrushes, starlings, swallows, tree sparrows, wrens, and many others - providing them all with an essential high energy diet.

Sunflower Hearts

The edible kernel of the sunflower seed, sunflower hearts offer the highest calorific value of any individual seed for wild birds. They are more expensive than black sunflower seeds but they have two advantages. First, the birds can feed more quickly because they do not have to remove the husk. Second, the lack of the husk means that there is no unsightly pile of husks left behind on the ground after the birds have had their fill. Sunflower Hearts are an excellent, very high 'energy content' food, with all year round appeal for a wide variety of birds. Whether they are fed from a seed feeder, bird table or on the ground, 'top-ups' will be needed far more frequently than with most other bird foods in order to retain the high level of species that sunflower hearts will attract.

Niger seeds

These are small and black with a high oil content and require a purpose designed feeder due to their smaller size. Niger seed is often used as a 'tonic' for birds. It is becoming increasingly popular, and has helped reverse the fortunes of the once diminishing goldfinch. Feeding niger seed is the most effective way of attracting this most colourful of residents, and it is also popular with other species such as greenfinch, siskins, and dunnocks. Niger seed is recommended for all year round feeding, with regular amounts for those wishing to retain their precious goldfinches, for once supplies stop, they will look somewhere else.

Peanuts

These are rich in fat and are popular with tits, greenfinches, house sparrows, nuthatches, great spotted woodpeckers and siskins. Crushed or grated nuts attract robins, dunnocks and even wrens. Nuthatches and coal tits may hoard peanuts. They provide excellent all year round high energy, protein and oils, which are so necessary in the busy spring and summer month - and absolutely essential in the winter. As fledglings receiving food from a parent can only manage smaller pieces, it is most important that peanuts are only offered from a wire-mesh peanut feeder - particularly during the breeding season. Peanuts can be high in a natural toxin called aflatoxin, so buy buy good quality peanuts from a reputable source and avoid any that show any signs of mould. Keep you peanuts in a cool and dry environment and buy them in small quantities, so that they do not sit around for too long. Salted or dry roasted peanuts should not be used.

Fat Balls and Food Bars

Fat balls and other 'fat-based' food bars are an extremely popular high-energy food source for wild birds, and are especially beneficial in the winter and during colder spells. If they are sold in nylon mesh bags, always remove the bag before putting the fat ball out - the soft mesh can trap and injure birds. You can also make your own bird cake by pouring melted fat (suet or lard) onto a mixture of ingredients such as seeds, nuts, dried fruit, oatmeal, cheese and cake. Use about one-third fat to two-thirds mixture. Stir well in a bowl and allow it to set in a container of your choice. An empty coconut shell, plastic cup or tit bell makes an ideal bird cake 'feeder'. Alternatively, you can turn it out onto your bird table when solid.

Mealworms

Mealworms are not worms but the larval stage of a beetle and are a natural food and can be used to feed birds throughout the year. They are the larvae of the Yellow Mealworm Tenebrio molitor that are used widely as food for wild birds, as well as captive birds, reptiles and amphibians. Another less common but similar species, the Dark Mealworm Tenebrio obscura is sometimes used, the larva being somewhat smaller in size. Mealworms are relished by robins and blue tits, and may attract other insect-eating birds such as pied wagtails. It is very important that any mealworms fed to birds are fresh (either live or dried). Any discoloured ones must not be used as they can cause problems such as salmonella poisoning.

What to Avoid...

Cooking Fat

Fat from cooking is bad for birds. The problem with cooked fat from roasting tins and dishes is that the meat juices have blended with the fat and when allowed to set, this consistency makes it prone to smearing, not good for birds' feathers. Cooking fat is also a breeding ground for bacteria - so potentially bad for birds' health. Salt levels depend on what meat is used and if any salt is added during cooking. Lard and beef suet on their own are fine as they re-solidify after warming and as they are pure fat, it is not as suitable for bacteria to breed on.

Polyunsaturated Margarines or Vegetable Oils

These are unsuitable for birds. Unlike humans, birds need high levels of saturated fat, such as raw suet and lard. They require a high energy content to keep them warm in the worst of the winter weather - since their body reserves are quickly used up, particularly on cold winter nights. Polyunsaturated margarines or vegetable oils are soft fats which can easily be smeared onto the feathers, destroying their waterproofing and insulating qualities.

Dry Dog and Cat Food

Dry dog or cat biscuits are not recommended as birds may choke on the hard lumps. It is sometimes added to cheaper seed mixtures for bulk. Soaked dog or cat biscuits are fine, except in hot weather as they quickly dry out. Meaty tinned dog and cat food form an acceptable substitute to earthworms during the warm, dry part of the summer when worms are beyond the birds' reach. Blackbirds readily take dog food, and even feed it to their chicks. The drawbacks are that pet foods can attract larger birds such as magpies and gulls, and also predators such as neighbourhood cats. If this is likely to be a problem, it is best avoided.

Milk and Desiccated Coconut

Never give milk to any bird. A bird's gut is not designed to digest milk and it can result in serious stomach upsets, or even death. Birds can, however, digest fermented dairy products such as cheese. Mild grated cheese can be a good way of attracting robins, wrens and dunnocks. Give fresh coconut only, in the shell. Rinse out any residues of the sweet coconut water from the middle of the coconut before hanging it out to prevent the build-up of black mildew. Desiccated coconut should never be used as it may swell once inside a bird and cause death.

Mouldy and Stale Food

Many moulds are harmless, but some that can cause respiratory infections in birds, and so it is best to be cautious and avoid mouldy food entirely. If food turns mouldy or stale on your bird table, you are probably placing out too large a quantity for the birds to eat in one day. Always remove any stale or mouldy food promptly. Stale food provides a breeding ground for salmonella bacteria, which can cause food poisoning. At least one type of salmonella causes death among such species as greenfinches and house sparrows. Large quantities of food scattered on the ground may also attract rats and mice.