Bathing & Preening

Bathing and preening are both aimed at looking after the bird's feathers, because if they become damaged the bird cannot fly and so can neither escape from predators or search for food. The bird also becomes susceptible to extremes in temperature, especially the cold weather, because it cannot fluff up its feathers to keep warm.

You can encourage birds to bathe in your garden by providing water in a bird bath.

Bathing

Nearly all birds bathe frequently in water to keep their feathers in tip-top condition, though Starlings, Blackbirds and House Sparrows are the ones we are most likely to see. During the summer, bathing in water also helps the bird to keep cool.

Once in the water, the bird fluffs its feathers to expose the skin, submerges its belly and breast in the water, rolls back and forth by dipping its head into the water and creates a shower by flicking its wings. When finished, the bird shakes off the excess water and then flies off somewhere to dry and preen.

Some birds, for example House Sparrows, take dust baths (often after a water bath) by rolling about in dry dust or soil. The dust is thought to absorb excess preen oil and remove dry skin, lice, etc. Among your flowerbeds and planters you may find tell-tale bowl-shaped hollows where they have been bathing.

Blackbirds and other thrushes often sunbathe, laid down and with wings outstretched. The sun is thought to straighten the birds feathers and help the preen oil to spread through the feathers. Some ornithologists have suggested that it may also draw parasites to the surface where the bird can remove them or that the ultraviolet light in the sunlight converts chemicals in the preen oil into Vitamin D. However, one could be forgiven for thinking that they simply enjoy it.

Additionally, some birds like Blackbirds, Starlings and Jays will adopt a sunbathing posture on an ants' nest, or even pick up ants in their bill and rub them on their feathers. Ornithologists believe the formic acid that the ants release may kill feather lice.

Preening

Preening is a seemingly more careful process than bathing and often follows bathing.

The bird gently strokes or nibbles along the barbs of each feather, starting at the quill and working towards the tip, so that they are properly arranged.

In addition, most birds have an oil-secreting gland, called the preen gland (or uropygial gland) underneath their tail - this is the Parson's nose on a chicken or goose. The bird rubs its bill against the gland and then spreads the oil over the surface of the feathers. This oil keeps the feathers flexible and aids waterproofing but also kills bacteria and fungi.

For some species of birds, for example wildfowl and seabirds, such as Mallards and Black-headed Gulls, oiling the feathers is particularly important to that the feathers do not become water-logged while in the water.

Some other species, such as Wood Pigeons, do not rely on oil but on a waxy powder for keeping the feathers flexible and waterproof. The waxy powder comes from special feathers called powder down.