Taking a miracle for granted


The Most Perfect Thing – Inside (and outside) a bird’s egg, by Tim Birkhead (Bloomsbury)

WE take eggs utterly for granted. There they are, cream or brown or speckled, in their clever natural packaging, waiting to be boiled, fried or beaten.

Yet, seen through the eyes of British ornithologist Tim Birkhead, they are little miracles.

Hen’s eggs, the ones we buy from the supermarket, are unfertilised and unincubated, so we see only a fraction of the miracle they are, he says.

“Our familiarity with the eggs of one species has blinded us to the extraordinary diversity of egg size, shape and structure across the 10 thousand other species of birds that currently exist in the world.”|

Birkhead has made a career studying guillemots, northern hemisphere seabirds that nest on cliffs and lay eggs of an astonishing variety of size and colour.  In fact these eggs were the most popular and sought after for collections because of their variety, beauty and odd, pointy shape. (See the eggs on the cover of the book.)

Birkhead decided to write this book after watching a natural history programme in which the presenter said guillemot eggs were pointy at one end so they could spin on their axis and not roll off a narrow cliff edge.

This is not true, and he was surprised that the presenter had said any such thing. And so he decided to reinvestigate the eggs of the guillemot, and other birds, and the result is this mostly fascinating book (although he sometimes gets a bit carried away by his enthusiasm).

He’s very good at explaining things to lay readers (forgive the pun). If you’ve ever put a raw egg into vinegar and left it there for a couple of days, you’ll know the vinegar dissolves the shell so that you’re left with a sort of balloon filled with liquid.

This is how the egg starts off, before the shell, and he says as the egg moves down the oviduct (egg tube) it is sprayed by dozens of tiny aerosols depositing a solution of calcium carbonate on to the balloon surface. After about 20 hours, when the shell is more or less complete, another set of aerosols squirt out coloured dyes for the ground colour of the egg, and then others create the spots and streaks on the egg surface.

He writes about the shape of an egg, the colouring, what albumen (egg white) does (it naturally resists bacterial infection, thanks to an enzyme that is also found in our tears and saliva), what the yolk does, fertilisation, laying, incubation and hatching. The first gulp of air a check gets is from the bubble at the blunt end of the egg that you will see when you crack open a boiled egg.

He talks about the importance of long-term studies, not just of guillemots, or indeed of birds. But at a time when scientific funding is drying up – Birkhead’s own 40-year study of guillemots lost its funding in 2013 – he emphasises why long-term studies are vital.

“Perhaps the single most important aspect of long-term studies is that they will allow us to investigate environmental problems that we haven’t yet even imagined. Just as museum eggs collected for one purpose in the 1800s and 1900s were later used to look at the effects of acid rain and to establish pesticides as the cause of hatching failure in raptors, long-term ecological studies are an investment in our environmental future.”

Just this past week a local newspaper ran an article about a sample of 1 347 birds in American museums dating back to the early 1900s, and how studying them had helped solve a climate change mystery.

Scientists from the University of Chicago compared these birds with others of the same species collected a few decades later, and found the early birds carried more soot in their feathers than in the 1930s, when homes turned away from coal for heat.

The article pointed out that this was useful for climate change studies because it was difficult to study century-old soot – or black carbon – because it doesn’t hang around in the atmosphere. But it was still there, trapped in the birds’ feathers.

If that kind of thing interests you, you’ll find Birkhead’s book full of astonishing and captivating facts. It’s thoroughly worth the read.

  • This review also appears in Weekend Argus on Sunday today, October 15.



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