Stone the crows

BBC: Attempt to save declining lapwing

A five-year project has been launched to halt the decline of the lapwing, a bird traditionally known as the "farmer's friend".

More than 250 farm sites have been chosen to test measures designed to help the species recover.

Lapwing numbers have declined in the UK by almost 50% since 1970.

The article goes on to explain that the decline is believed to be due to modern farming practices, such as the loss of mixed agriculture, and the draining of land. This may well be correct, but I think there might be another reason, also linked with changes in farming practices:

I live in the South Pennines. Lapwings are one of my favourite birds. A pair of them nests in the fields behind my house every year. I have spent many an hour watching them from afar, and would be truly amazed if they have ever managed to rear a brood successfully. The reason: carrion crows. There are hundreds of them in these parts, and the poor lapwings seem to spend the whole of the nesting season fighting them off. I can't believe any of the eggs/chicks survive the onslaught. Indeed, I was talking to someone about it only last week, and he said that, this summer, he witnessed a carrion crow flying off with a young lapwing chick.

And why are there suddenly so many carrion crows? I would guess it's because so few farmers are shooting them any more. The laudable clampdown on firearms in recent years, and the public's disapproval of shooting birds have meant, I would hazard a guess, that crow numbers have increased in recent years, with disastrous consequences for lapwings.

Well, that's my theory at least, and I'm sticking to it.

Tenuous links

I appreciate I'm probably being a bit unfair quoting from a brief news article, but is this a total non-story or what?

BBC: Study uncovers 'chimp cross code'

Experts studying chimpanzees while investigating the evolution of human social behaviour have uncovered their ability to safely cross roads.

They said the discovery has shown chimps' ability to cope with the risk of man-made situations…

It found the dominant adult males took up protective positions in the group when it was tasked with crossing roads…

The study has built on prior research showing that adult male monkeys took similar action to reduce the risk of being attacked by predators when travelling towards potentially unsafe areas, such as waterholes.

Kimberley Hockings, who worked on the study, said: "Road-crossing, a human-created challenge, presents a new situation that calls for flexibility of responses by chimpanzees to variations in perceived risk, helping to improve our understanding about the evolution of human social organisation.

In other words, what they appear to be saying is that, when presented with an unusual and/or potentially dangerous situation, dominant male chimps and monkeys take protective positions in front of and behind the group. An interesting, if pretty unsurprising observation.

But why do the people carrying out the study think that road-crossing presents a new situation that calls for flexibility of responses? Aren't the chimps simply giving a perfectly normal response when presented with a potentially risky situation? And why on earth do they think this is going to teach us anything about the evolution of human social behaviour? Don't loads of other animals (elephants, for example) do exactly the same thing?

I'm sure we can make certain inferences about the evolution of human behaviour by studying chimps, but I can't help feeling people read far too much into such studies. Why not study the chimps for their own sakes, rather than trying to bring in pretty tenuous links to human behaviour?

Swallows preparing for migration

Swallows feeding
Adult swallow feeding its young.

It's getting to be what the locals around here refer to as a little back-endish—by which they mean summer is on its way out, and autumn approaches.

Returning to my house today, I spotted several swallows congregating on the nearby telephone wires. At this time of year, this is a clear sign that they are preparing to migrate south for the winter. As they appeared to be fairly settled, I grabbed my camera and walked back down the hill to fire off a few photographs. It turned out that the swallows on the telephone wires were recently fledged juveniles, who were waiting to be fed. I watched for ten minutes or so as their parents gathered flies over the adjacent fields and returned to feed their young.

By coincidence, I am currently reading Richard Mabey's biography of the famous Eighteenth Century naturalist, Gilbert White (Amazon UK), who was an early influence on Darwin. White was fascinated by swallows. Their annual appearance in spring and disappearance again in late summer was still a mystery during his lifetime. In February, 1769, he wrote to his friend, Thomas Pennant:

When I used to rise in the morning last autumn, and see the swallows and martins clustering on the chimnies and thatch of the neighbouring cottages, I could not help being touched by a secret delight, mixed with some degree of mortification: with delight to observe with how much ardour and punctuality those poor little birds obeyed the strong impulse to migration, or hiding, imprinted on their minds by their great Creator; and with some degree of mortification, when I reflected that, after all our pains and inquiries, we are yet not quite certain to what regions they do migrate; and are still farther embarrassed to find that some do not actually migrate at all.

To his dying day, White never did find out for certain whether swallows migrated or hid (by which he meant hibernated). We now know that swallows migrate from Britain to South Africa during our winter: a phenomenal journey for such a small bird. And we now know that this impulse to migration is not imprinted on their minds by a creator, but by evolution.

Darwin was right: there is grandeur in his view of life.

Woodpeckers' toes and woodpeckers' kludges


I spent some time reading up about woodpeckers yesterday morning. There is a great spotted woodpecker which visits the bird feeder in our garden most days. Never ones to avoid clichés, we have nicknamed him Woody. On Friday, I managed to get this photograph of him.

Woodpeckers' toes are a familiar example of an evolutionary adaptation. Instead of the usual (in birds, at least) three toes pointing forward and one toe back, most woodpeckers have two toes pointing forward and two back. This adaptation makes it easier for them to cling to tree trunks.

Yesterday, I learnt that the scientific adjective to describe this toes-in-pairs phenomenon is zygodactyl. Apparently, several different lineages of birds (including parrots and treecreepers) have independently evolved zygodactyl toes for clinging to tree trunks—demonstrating that Nature isn't afraid of reinventing the wheel.

Then I remembered that Darwin had written about woodpeckers in Origin of Species:

As we sometimes see individuals of a species following habits widely different from those both of their own species and of the other species of the same genus, we might expect, on my theory, that such individuals would occasionally have given rise to new species, having anomalous habits, and with their structure either slightly or considerably modified from that of their proper type. And such instances do occur in nature. Can a more striking instance of adaptation be given than that of a woodpecker for climbing trees and for seizing insects in the chinks of the bark? Yet in North America there are woodpeckers which feed largely on fruit, and others with elongated wings which chase insects on the wing; and on the plains of La Plata, where not a tree grows, there is a woodpecker, which in every essential part of its organisation, even in its colouring, in the harsh tone of its voice, and undulatory flight, told me plainly of its close blood-relationship to our common species; yet it is a woodpecker which never climbs a tree!

As usual, Darwin hits the nail on the head: although evolution through Natural Selection provides organisms with adaptations ideal for certain environments, so might a benevolent creator. But to see an animal, such as a woodpecker, with adaptations better suited for one environment, living in a very different environment is the best sort of proof that something has changed (for which, read evolved). A few paragraphs later, Darwin continues:

He who believes that each being has been created as we now see it, must occasionally have felt surprise when he has met with an animal having habits and structure not at all in agreement. What can be plainer than that the webbed feet of ducks and geese are formed for swimming; yet there are upland geese with webbed feet which rarely or never go near the water…

He who believes in separate and innumerable acts of creation will say, that in these cases it has pleased the Creator to cause a being of one type to take the place of one of another type; but this seems to me only restating the fact in dignified language. He who believes in the struggle for existence and in the principle of natural selection, will acknowledge that every organic being is constantly endeavouring to increase in numbers; and that if any one being vary ever so little, either in habits or structure, and thus gain an advantage over some other inhabitant of the country, it will seize on the place of that inhabitant, however different it may be from its own place.

No matter how well Nature might hone certain species to certain environments, it can only work with the material (species) already available to it—so species' ancestral heritages often show through in their current designs. Stephen Jay Gould referred to this phenomenon as the Panda's Thumb, but I like to think of it as Nature's Kludges.

See also: Can Red Lions Evolve?

When the infallible embraces the unfalsifiable

I promised myself I wasn't going to waste any time getting embroiled in the evolution v creationism non-debate on this website, but…

Guardian: Pope prepares to embrace theory of intelligent design

Philosophers, scientists and other intellectuals close to Pope Benedict will gather at his summer palace outside Rome this week for intensive discussions that could herald a fundamental shift in the Vatican's view of evolution.

There have been growing signs the Pope is considering aligning his church more closely with the theory of "intelligent design" taught in some US states. Advocates of the theory argue that some features of the universe and nature are so complex that they must have been designed by a higher intelligence. Critics say it is a disguise for creationism.

Just for the record, what a total tosser!

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