Michael Viney: Push and pull of genetic drive and environmental sway

Another Life: A single gene, dopamine receptor D4, is a strong influence in animals and humans

The little mob of house sparrows monopolising our bird feeders must, I suppose, be something of a privilege, given their drastic European decline. It’s quite unfair, in all their shades of brown, to find them boring. But birds by the dozen don’t invite much speculation on avian personality, while the fluffy great tits lower down the tube are a species analysed to bits.

It’s a couple of decades since research into octopus intelligence raised the issue of personality – unique patterns of thought, feeling and behaviour – in non-human species. A new field of experiment has since extended to bird behaviour. The intelligence of crows was widely recognised, but the personality of birds in general remained obscure.

Some research has explored the balance between genetic drive and environmental influence, the nature/nurture question long familiar from studies of human behaviour. At the University of Memphis, for example, the stress hormone corticosterone proved highest in the blood of baby jays in the nests of the least attentive mothers. Months later, these levels matched their fearfulness in tests to measure “boldness”.

In both animals and humans, a single gene, the dopamine receptor D4, is known to influence the seeking of novelty and curious exploration. The skilful agility and aerobatics of the great tit helped to make it the standard choice for European research.

READ MORE

Much of it has happened at Oxford University, a leading centre of ornithology and with the great asset of Wytham Woods, a nearby “laboratory with leaves”, bequeathed to the university in 1942. Its entire 358 hectares of old broadleaf woodland have held some 1,000 nest boxes, allowing individual marking of bird parents and offspring, spanning some 40 generations. This is one of the longest running ecological studies in the world.

The study of great tit personality is relatively new and has prompted parallel experiments in the Netherlands and at University College Cork.

The UCC study is led by Dr John Quinn, a behavioural ecologist who worked for four years with the great tits of Wytham Woods. Moving to Cork as professor of zoology, Quinn has been setting up studies on the birds that nest in woodland along the Bandon Valley.

These have already shown that bolder, more proactive males choose their partners sooner in winter and pay them more attention before breeding in spring begins. Shy males are less devoted to forming a strong pair bond and spend more of their time flocking with other females.

For more recent experiments, 49 great tits were caught in the wild and held in an aviary on the UCC campus. They were housed in individual plywood cages and fed sunflower seeds, peanuts and water “with added vitamin drops”.

How the boldness of birds affects their success in feeding and survival has been well studied, but the Cork team wanted to see if the birds had self-control to give them more flexibility in foraging.

They had in mind a classic behavioural test of delayed gratification in humans. Stanford University gave children the choice between a single marshmallow now or several marshmallows a little later. Most of them couldn’t wait and took the single marshmallow. (They were, of course, Americans.)

‘Good self-control’

The UCC researchers trained the great tits to find hidden food by pecking at a hole in the side of a tube they couldn’t see through. Presented with a transparent tube full of food, many of the birds pecked directly at the impenetrable plastic in front of them; others “showed very good self-control” by nipping round the side to feed.

Quinn, who led the experiment, suggests such studies show that the very small brain of the great tit “is capable of many sophisticated cognitive capacities”, often similar to our own, that help in facing constant life and death decisions. How far self-control is useful in the wild remains to be explored.

Knowing more of what helps birds to survive is no guarantee that they will. But the more attention of all kinds is focused on the natural world, the better the chance of giving it some proper respect.

Watching the great tits attacking the peanut feeder outside my window, I have little hope of telling one from another or judging any difference in behaviour. For that I would need different rings on their legs, like those fitted by the Cork researchers.

I like to help keep alive the recognition due to one James Parsons Burkitt, a county surveyor of Fermanagh. In the 1920s he trapped his garden robins and fitted them with different-shaped rings (Burkitt was colour blind). In a paper for British Birds, this launched the technical revolution of colour ringing that has underpinned research ever since.