Why Do Birds Open Their Wings? (5 Key Reasons + Sunning Explained)

Vultures, hawks, cormorants and storks can often be seen in what’s known as the “square stance” — perched with their wings spread as wide as possible, with their backs turned to the bright, direct sunlight.

But what is the purpose of this pose? Why do birds spread their wings when they’re not flying? Read on as we examine possible reasons why birds spread their wings.

Birds may spread their wings for many different reasons. These may be related to their habitat, such as helping dry wet feathers after a swim, raising body temperature quickly in cold weather, or exposure to sunlight as part of a regular feather care regime to help kill parasites.

Soaring birds are a common sight, gliding through thermals with their wings spread as wide as possible to benefit from the thermal’s updraft. However, many birds also engage in wing spreading when they are stationary on the ground, or perched in trees or on top of cliffs.

Some explanations may be as simple as drying off the body after swimming or underwater diving, and maximizing body heat by exposing large areas of feathers to warm sunlight.

For a more in-depth look at why birds spread their wings when they’re not flying, read on.

White-backed vulture (Gyps africanus) perched on top of a tree with spread wings, Kalahari Desert, Botswana

The Different Reasons Birds Spread Their Wings

There’s no single reason why birds are seen spreading their wings when they’re not flying, but here are a few suggestions that might hold the key to explaining this behavior.

Suning

John James Audubon, who first documented birds “basking” in 1831, noticed the behavior of a great egret, with its wings outstretched as it appeared to absorb the sun The heat of the light. On the warmest days, many birds can be seen with their backs to the direct sun to benefit from the intense heat.

Sunbathing helps birds dry off wet feathers and regulate body temperature after swimming or diving. It also helps groom and maintain feathers and can be used for pure enjoyment and relaxation.

Gray heron ‘basking’, catching rays with outstretched wings

to stretch

The spread wings release tension after flying or sleeping. If a bird settles in one position for too long, spreading the wings can improve circulation and help muscles relax. Spreading the wings and stretching can help blood flow, which is a common movement in birds before taking off.

Corn Bunting Spread Wings Stretch

Temperature adjustment

Spreading their wings helps some birds control their body temperature because they are able to expose the largest possible area to the sun’s rays. This allows them to absorb as much heat as possible through the wing surfaces and then use it as energy, avoiding depleting energy resources obtained from food.

Abdim’s Stork or White-bellied Stork Tanning

before they land

When a flying bird lands, spreading its wings as far as possible is a common technique used to gradually slow down and prepare for landing. Drag from as large a surface area as possible to allow the bird to descend in a controlled manner and land safely. Owls, eagles and other birds of prey can be seen using this method to ensure their flights end well.

Mallard ducks come to the icy lake

intimidate

By spreading their wings, birds can increase their perceived size and therefore assume a more intimidating appearance to repel predators and threats to their territory. Spreading wings to show dominance is a common behavior of geese and swans.

A pair of swans fighting

What is Bird Sunning?

If you’ve observed a bird for an extended period of time in warm weather, you’ve likely seen it “basking” — resting with its wings spread as far as possible in direct sunlight. The bird may be sitting on the ground or perch, or it may be standing, as is often the case with wading birds such as flamingos.

Spreading their wings and basking exposes the bird’s feathers to the maximum amount of sunlight and warmth. Many bird species regularly bask in the summer, including cormorants, flamingos, darters, robins, larks and pigeons.

Benefits of sunbathing

Basking in the sun offers a range of benefits to different birds, depending on the species and habitat. These include the following reasons:

drying

Birds that have spent long periods of time in, above or below water can often be seen in a position with their wings outstretched, with their backs facing the warm direct sunlight. Basking in the sun allows birds to speed up the natural drying process and avoid keeping wet, cold feathers for long periods of time.

Cormorants can often be seen perched on rocks or tall waterside trees with their wings outstretched. Also see swans, gannets, black-crowned parrots, black-bellied hens and pelicans with their backs and broad wings facing the sun as they dry their feathers.

Double-crested cormorant (phalacrocorax auritus) drying its wings

warmth

Birds that live in cold environments may take advantage of sunny days to maximize their body temperature. Stretching the wings and expanding the surface area exposed to the warming sun’s rays allows the birds to use the sun’s heat as energy needed to regulate body temperature.

Cold climate birds that use this technique include the Steller’s eider and the snowy owl. The turkey vulture lowers its body temperature overnight, becomes slightly hypothermic, and then rapidly warms up again each morning in the basking position.

For birds like snowy owls, the early morning sun position helps their body temperature return to normal levels more quickly

feather maintenance

For some sunbathing birds, intense sunlight can provide important benefits in promoting plumage health. Exposure to heat and light plays an important role in eliminating parasites in birds.

Sunlight can quickly heat a bird’s wing to around 70 degrees Celsius, hot enough to kill any lice or parasites that might live on the bird’s skin and feathers.

dress up

Additional feather maintenance benefits can be seen in the sun’s effect on the essential feather oils that birds produce to keep their feathers in top condition.

Exposure to sunlight helps the feather oil diffuse throughout the bird’s plumage and converts important compounds in the oil into vitamin D, which promotes the bird’s health.

For more information on collation, check out this guide.

Sanderling preening feathers

relaxation

Birds may just bask in the sun because they love it and find it relaxing. Whether sitting with their wings spread out in a sunny spot on a garden path, or spreading their wings to enjoy a sand bath, many bird species seem to jump at the chance to stop and bask in the sun on the brightest summer days.

Blackbirds, larks and finches are some of the most common birds that bask in the sun in backyards and lawns for fun.

Young female blackbird basking in the sun, on the grass

Why do birds spread their wings in the rain?

While many birds take cover when the showers begin, occasionally you may see birds engage in some rather unusual wing-folding activity when it rains.

Birds, especially wood pigeons and some pigeons, can be seen sitting flat on the ground, first extending one wing to one side of the body, and then after a while, alternately turning the other wing.

The reason for this is thought to be “rainbathing”, as opposed to sunbathing, which is especially common among rainforest birds, which use frequent showers to assist with regular grooming activities.