Feather Forensics

The text of this article was written to accompany a double-page spread in the September – October issue of RSPB Bird Life magazine (aimed older children) in 2011.

Feather Forensics: Who’s left their calling card in your garden?

Jessica Law investigates

jay feather

Autumn is upon us and the birds are lying low. After the breeding season, many birds are moulting like mad – shedding their old feathers and growing new ones. But even if you can’t see them, you can find the clues birds leave behind. Go out and look for the evidence.

First, find your feather.

 Under the microscope

Once you’ve found a feather, hold it against a dark background with the light behind you. You’ll see rows of “barbs” sprouting from the main shaft. These are secured together by tiny hooks. See if you can pull them apart and “zip” them up again.  Feathers are made from the protein keratin, which is light, flexible and strong: the same material that makes up your nails and hair.

Not just for flight…

Feathers also need to be watertight. You’ll see that birds spend a lot of time preening. This coats their feathers in waterproof oil and stops them getting waterlogged in the rain or when swimming. Have you ever seen the imprint of a ghostly bird on your window and wondered how it got there? It’s actually the feather oil and dust from a bird that crashed into the glass…

High maintenance

Birds spend a lot of time keeping their valuable plumage healthy and parasite free. You may have seen them at it:

Most birds bathe in puddles.

Birds in dry countries take dust baths.

Crows sit on chimneys to smoke the lice out of their feathers.

Jays stand in ant’s nests until the ants get angry and squirt a defensive chemical at them: formic acid. This is brilliant for killing off annoying feather mites.

Now for some Crime Scene Investigation

First, think about where you found your feather – Could it be a puffin?  Not if you live 50 miles from the sea! Its colour and shape can tell you what species it is, and which part of the bird it came from.  You can even look it up on the RSPB website:


Taking wing

This feather is from a black-headed gull. They thrive inland as well as on the coast. Its long, pointed shape tells us it’s a primary feather, used for flying. Take a look at this picture of a black-headed gull in flight. Judging by the feather’s black tip, where on the wing do you think it comes from?

Pointed feathers are OK for gulls, but if you were a stealthy hunter stalking your prey, raucous flapping wings wouldn’t do you any favours. That’s why owls have soft, downy feathers round the edges of their wings, to muffle sound.

A feather in your cap

This stylish striped feather comes from a jay, and can be found in forests or wooded gardens. This is a covert wing feather, which covers the base of the flight feathers. Jays are unusual because both males and females share the same fancy plumage.

Closer to home

Wood pigeon feathers like this are common finds in the garden. But this one is a funny shape, isn’t it? It gets wider towards the end – not very streamlined at all!

That’s because it’s actually a tail feather. Birds use their tails to stabilise themselves and keep their balance when flying, the same way a tightrope walker uses an umbrella.

Flights of fancy

You might find a mallard feather like this near a lake or river. This is also a tail feather, but it doesn’t seem very useful – what do you think it’s for?

This curly, iridescent feather is from a male mallard, who uses his bright plumage to attract a mate. Shiny, well-groomed feathers are a sign that the male is healthy and will make a good father.

Some bird species might look quite drab to the human eye. But birds can see an extra colour that humans can’t: Ultra Violet. Male blackbirds may look boring to us, but females find their ultra violet beak markings very dashing!

Case notes

So, what can the humble feather tell you? Just by looking at it, you can see what it’s used for – flight, decoration, insulation, or all three at once.

But the list doesn’t end there. You only need to go a little further afield for things to get seriously weird. In the tropics, Rufous hummingbirds use their feathers to communicate – as they fly, air rushes through tiny gaps in their wings, making a whistling sound. Club-winged manakins actually rub their wings together to make an eerie screeching noise.

If all this is possible, what else are feathers capable of? You’ll just have to go out there and investigate for yourself…

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