Wednesday, 26 April 2017

Choughs dust bathing – or is it showering?

Most birders are familiar with bird dust bathing and this behaviour has been well recorded in many species in many locations across the world.  

The Google search for “bird dust bathing” gives web sites providing information and photos of dust bathing and some describe and show birds rolling or moving around in an area of dust which understandably looks like bathing as in bathing in water in a bath. The following description of this behaviour is from:

Dust bathing (also called sand bathing) is an animal behavior characterized by rolling or moving around in dust or sand, with the likely purpose of cleaning fur, feathers or skin, and removing parasites.[1] Dust bathing is a maintenance behavior performed by a wide range of mammalian and avian species. For some animals, dust baths are necessary to clean the feathers, skin, or fur, similar to bathing in water or wallowing in mud.[2] In some mammals, dust bathing may be a way of transmitting chemical signals (or pheromones) to the ground which marks an individual's territory.

The description of dust bathing from Wikipedia suggests the reasons for this behaviour are two-fold, that is feather cleaning and parasite control.

Sunning and anting are two other closely related behaviours and these are also thought to be for parasite control.

Recently I observed six White-winged Choughs (Corcorax melanorhamphos) applying a fine silty/clayey soil to their feathers, however in this case the birds were not bathing or rolling in the dust, they were applying the dust and soil with their bills, scooping up large bills full and inserting this deep within their back and breast feathers. As they did so, some of the liberally applied soil spilt over their outer feathers. I think this was accidental and the bird’s primary purpose was to apply the soil within the body feather layer, that is it was not intended as a surface treatment!

The soil was sourced from small holes excavated by the Choughs using their bills. I cannot say if the holes were excavated with the sole purpose of obtaining fine soil for their dust bathing or if initially they were dug in pursuit of insect food. In this instance the birds had a series of about five similar sized holes spread along a line about 2 metres long. The birds worked individually at the holes and then sometimes up to four birds would gather around one hole, all applying soil to their feathers – you could call it communal bathing I guess!

Three Choughs at one of the dust holes all working to apply dust using their bills.

Here the bird on the left is inserting soil with its bill into the back feathers while excess soil showers down the bird’s flank.
A second closer shot showing the same bird in the photo above.

 Judging by the brown eyes at least two of the six birds were immature.

This young bird shows how the body feathers were being fluffed up as part of the dust application process.
A red-eyed adult bird at one of the dust holes.
Four birds at one dust hole.
Adult bird at a dust hole.
Another bill full of soil being applied to feathers.
Same bird as a above working the soil into the back feathers.

I thought this observation of Choughs using their bills to apply to their feathers the dust and soil they have obtained from holes they have prepared, was worth reporting in a blog post. As to the purpose – feather cleaning or parasite control, or perhaps both – I am not able to say.

I had set out with my camera to see if I could find and photograph a couple of Scarlet Robins seen earlier in the day and while I managed to do this the unexpected discovery of the Choughs applying dust to their feathers was a real bonus. It just goes to show that when you head outdoors with the camera you never know what you are going to find. This for me is one of the great joys of birding and nature observation – expect the unexpected.

You know summer has passed and autumn is well underway when, following their summer breeding within the forest, Scarlet Robins come to the margins of the forest and to more open country and use farm fences as part of their “perch and pounce” hunting technique. A pair of Scarlet Robins working a fence line brings joy to a brisk autumn or winter morning.

Female Scarlet Robin
Male Scarlet Robin

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