By Bjorn Blanchard

On a cold morning walk through the Upper Dulwich Wood in early April, with branches still dripping with the previous night’s rainfall (what a wet winter!), I noticed a coin lying exposed on a shallow slope. I picked it up and wiped it clean: a 1970 five ‘new pence’ piece. At home I compared its size to the modern ten pence. They made coins bigger then: it was nearly as large, and certainly twice the size of today’s five pence. It tells a story about the shrinking effect of inflation on coinage over the past forty-five years!

Inflation is an immutable law of economics and is linked to the abundance of money and the things that money buys. Economics also explains why common things attract a lower price than the scarce, a phenomenon that has its analogue in our appreciation of nature: as creatures become more plentiful we take them for granted, consider them two-a-penny, whilst caring more for those that are scarcer. The point is well illustrated by the contrasting fortunes of the Wood Pigeon - a common bird in Upper Dulwich Wood, and a species that we pay little attention to (the British Trust for Ornithology says that remarkably little is know of its ecology, probably because it is a hum-drum, everyday sort of animal) - and the Turtle Dove, which is red-listed as a bird of conservation concern.

Over the last 45 years - when that five pence coin was minted - the population of the Woodpigeon has almost doubled according to the BTO’s 2007-11 Bird Atlas. By contrast its close cousin, the Turtle Dove, has declined by nearly three quarters between 1970 and today. The bird is now confined to a few areas in the UK, its decline has been so dramatic; sadly, there were no confirmed breeding pairs of Turtle Dove in London and the Home Counties in the 2007-11 BTO counts.

So, what explains the rise in numbers of the Woodpigeon and the decline of the Turtle Dove? The Woodpigeon sticks close to home and feeds opportunistically. Its sedentary habits protect it from indiscriminate killing each spring and autumn that the Turtle Dove face as it migrates across Mediterranean countries from Africa to Europe and back again.

Nor is the Woodpigeon subject to the pressures on its habitat that affect the Turtle Dove in its African wintering grounds. Woodpigeons benefit from year round supplies of food, including the early winter-planted oil seed rape which farmers started sowing as a commercial crop in the 1970s. Woodpigeon have also taken advantage of the rise, over the same period, of households feeding seeds and nuts to garden birds, at least judging by the number of Woodpigeons that congregate at the bottom of my squirrel-proof bird feeders, picking the crumbs that drop from above.

The Upper Dulwich Wood is a favoured roost for the Woodpigeon through all four seasons, and I regularly count birds into double figures during autumn and winter; in spring several pairs nest in the Woods. Whilst it is right to be concerned at the decline of the Turtle Dove, we might also celebrate the abundance of the Woodpigeon. At the very least we should not be complacent: the Passenger Pigeon was one of the world’s most numerous bird but hunted to extinction within one hundred years, the last dying in 1900.

Switching to another member of the dove family: the very common and much overlooked feral pigeon, this from Philip Larkin, writing in 1955:

On shallow slates the pigeons shift together,
Backing against a thin rain from the west
Blown across each sunk head and settled feather.
Huddling round the warm stack suits them best,
Till winter daylight weakens, and they grow
Hardly defined against the brickwork. Soon,
Light from a small intense lopsided moon
Shows them, black as their shadows, sleeping so.