Blue Is The Colour For 2020 But Not For Birds
Pantone’s colour of the year for 2020 is 19-4052 Classic Blue. Pantone said they chose it because it instils calm, confidence, and connection, highlighting our desire for a dependable and stable foundation on which to build as we cross the threshold into a new era.
Colour theorists say blue is a colour that can bring on feelings of calm. It can slow your heart rate, lower your blood pressure, and reduce anxiety. It is associated with open spaces and freedom and is thought to be the world’s most popular favourite colour.
The choice got us thinking about how much blue we find in nature. Pantone said Classic Blue is suggestive of the sky at dusk, but blue is also the colour of oceans, deep lakes, and icy mountains.
However, it’s also the rarest occurring pigment found in the natural world so when we start to think about plants and wildlife blue becomes much more elusive.
The poison dart frog, and the blue tang, the little fish that appears in Finding Nemo, immediately spring to mind. And there are blue snakes, blue lizards, and a blue iguana. There are blue butterflies – one of the UK’s best-known butterflies is the common blue – and of course there are many blue birds.
Trick of the light
The UK has the kingfisher, the barn swallow, and the blue tit, and when you go further afield there are blue hummingbirds, blue parrots, blue bluebirds (obviously), blue jays, blue peafowl, and blue buntings.
But when is a blue bird not really blue? The answer is ‘all the time’. If we were to be pedantic there are actually no blue birds.
Some birds with red and yellow feathers get their colours from the food that they eat. Flamingos, for example, are pink because of a certain type of shrimp in their diet. But for most birds it’s not dyes and pigments that colour their feathers. Instead, birds use well-controlled changes to the nanostructure of their feathers to create vivid colours, probably to help them recognise each other.
For example, jays’ feathers are constructed from a nanostructured spongy keratin material, exactly the same substance that makes up human hair and fingernails. When light hits the feathers the size of the holes in the sponge-like structure determines how the light is scattered and therefore the colour that is reflected. In jays this ranges from ultra-violet through to blue and white.
Jays are able to demonstrate amazing control over the size of these holes and fix them at particular sizes, determining the colour that we see reflected from the feather. Larger holes mean a broader wavelength of light is reflected, which makes the colour white, while smaller holes result in the colour blue. Under ultraviolet light a blue feather may look grey or brown to the human eye. And if you were to grind up a blue feather the resulting particles would be brown.
You don’t even need a UV light source or a pestle and mortar to prove this. Just turn over a blue feather and what do you see? The prism is now the wrong way round, the scattering of light does not happen, and so all you see is a grey or brown feather.
These structural colours explain why non-iridescent structural greens are rarely found in nature. To create the colour green a very complex and narrow wavelength is required, something that is hard to produce by manipulating these spongy structures. Nature’s way to get around this and create the colour green – an obvious camouflage colour – is to mix the structural blue like that of the jay with a yellow pigment that absorbs some of the blue colour.
Structural colours also explain why birds don’t go grey with age – in feathers, unlike in human hair, there is no pigment to fade over time.
Blue, red and grey
And what about those most famous of British blue birds that flew over the white cliffs of Dover? A number of suggestions have been put forward about the types of birds Dame Vera Lynn sang about in 1942. Perhaps they were swallows or peregrine falcons. Or maybe they were symbolic of the blue uniform of RAF pilots, or a hope for blue skies to replace the gloomy clouds of war.
The answer is regrettably a little more mundane. Nat Burton, the American lyricist who wrote the words to (There’ll Be Bluebirds Over) The White Cliffs of Dover, had never visited Britain and therefore was not aware that bluebirds were not indigenous to the UK.
At Bird Spot we’re happy with Pantone’s colour choice. Blue is our favourite colour and the blue tit is one of our favourite birds.
As we usher in a new decade we know there may be some big changes ahead for the UK. But however things turn out our hope for 2020 is that people continue to become more aware of the natural world around them, and that we keep caring for birds whatever their colour, so that the future for our feathered friends and the next generation isn’t so blue.
Happy New Year’s Eve from the team at Bird Spot x