8th June 2025
The Handicap Principle
We’ve just returned from a ten-week trip to
the UK. It’s so good to be home – but while we were away, I did manage a couple
of short excursions with my camera (and Miriam).
I was lucky enough to photograph two of the
most beautiful brightly coloured birds that we see in the UK. In both cases the
birds are the male of the species, while their missus is considerably less
colourful, perhaps even dully coloured. The mandarin drake is, thought by many
to be, the most exquisitely coloured duck in the world, while Mrs Mandarin,
though beautiful in her own way, has plumage that nicely blends in with the
riversides and edges of lakes that she frequents. Similarly, Mrs Pheasant pales
into insignificance when compared to the vibrant colours of her bloke, the cock
pheasant. But not all female birds are less flamboyant than their male
counterparts – take the kingfisher for example, the male’s stunning electric blue
and orange is matched almost exactly by his consort’s, the ‘queenfisher’.
One might ask why any birds have eye-catching
plumage – wouldn’t all birds be safer with dull colours providing camouflage to
make them less noticeable to those that would lunch on them? And if there is a
good reason for some birds to be so colourful, why particularly the males and
why are some, but not all, females brightly coloured too?
All birds (male and female) are interested
in self-preservation, as indeed are all animals and people. And so, the
starting point is for birds to be coloured in a way that doesn’t attract
attention. But birds and animals have an inbuilt desire to reproduce to maintain
their species. And to do this, males or females have to pursue a mate.
For most bird types it’s the females that
are in charge of rearing chicks and they want to choose the ‘best’ mates. They
look for the most virile male they can find, hoping that their chicks will be
strong and therefore more likely to survive. So, males have to make sure they
look good and that the females will find them attractive. With this in mind, many
males evolve into colourful birds. But the brightness of the plumage gives the
bird a distinct disadvantage – it’s easily spotted by predators. So, the more
attractive it is to females, the more noticeable it is to predators – a bit of a
catch-22 situation for the poor male birds. This phenomenon is known as the
‘handicap principle’, a hypothesis proposed by the Israeli biologist, Professor
Amotz Zahavi. He suggests that to show its physical prowess, which makes it
more attractive to a female, the male will put itself in danger, a sort of
message to the female that he’s strong enough not to have to worry about
predator threats. It’s a bit like the birds are playing ‘chicken’ - a high-risk
policy indeed!
Meanwhile for Mrs Pheasant to rear her
brood it is much safer for her to stay out of the spotlight. If she were more flamboyant,
she’d be easy meat for a fox. Likewise, Mrs Mandarin would be a sitting duck if
she were easily noticeable in her nest.
So, what of the kingfisher’s ‘queen’? How
can she afford the risk of being so startling? She hunts for fish and small critters just
like the king himself, but when it comes to nesting, she’s not at all
noticeable in her bankside burrow and so can afford the luxury of being the rainbow
queen – as WH Auden wrote ‘It was the Rainbow gave thee birth/ And left
thee all her lovely hues’. But we still need to understand what benefit she
gets from her vivid colouring. It’s hard to believe but actually the bright colours
act as camouflage as kingfishers fly above rivers, they blend in with the
foliage and are not as noticeable to the fish below the surface of the water.
So there she has it – her catch of twenty-two!
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