From urban foxes to suburban songbirds: Culchies and townies in the animal and bird world
In Sweet Culhane Home Monkstown, Pole Caoimhe Tits Traffic Picture: In Home: Blue Nesting A Dublin Light
— Oliver Goldsmith
‘Coillte Maghagh’, the wood of Fir Bolg chieftain Maghagh, has given its evocative deep-throated name to blow-ins living in Dublin. As a Limerick-man, I rejoice in being a ’culchie’. But is the genus limited to humans? Dublin teems not only with human culchies, but with mammal and bird ones as well.
An extra-terrestrial sociologist, studying our behaviour, would be intrigued by the mass movement of people from the countryside to the towns in recent decades. More than half of the world’s population now live in cities and numbers are expected to double by 2050. More than 54% of Irish people are urbanites. Not that the movement is entirely in one direction. Forsaking the rat-race and traffic-choked claustrophobia of crowded concrete jungles is becoming increasingly attractive, particularly to those of us ‘getting on in years’.
An extra-terrestrial zoologist, likewise, would note that the urban fox is now firmly established and indeed seems more prosperous than its rural cousin. Grey squirrels, in retreat from the pine marten, are finding city parks much to their liking. Even peregrines, banished to remote mountains and coastal cliffs until recently, now nest in the nooks and crannies of high-rise buildings. The steady supply of city pigeons — food for raptor chicks — is a welcome bonus.
The redistribution of songbird populations is particularly striking. Birds of the woodland fringes and rural hedges — thrushes, tits, and sparrows — thrive in the leafy suburbs despite the presence of lethal cats. But how rigid is the urban-rural songbird divide? Research in Scotland suggested that the apartheid may be rather limited. Using a technique known as meta-barcoding, scientists found garden-bird food residues in bird droppings hundreds of metres from the nearest dwelling. Perhaps city birds, like their human counterparts, have lingering yearnings for the rural idylls of their forebears.
Hammer’s team managed to re-sight 61 of the ringed blue tits and 44 of the great tits. Rural ringed birds, he found, travelled greater distances, between winter and the following breeding season, than did urban ones. Urban ringed individuals tended to remain in the city throughout all seasons, whereas 46% of the blue tits and 80% of the great tits moved from rural locations to urban ones. Only 14% and 7% respectively moved in the opposite direction.
"Lots of questions remain", Hammer admits, but "overall, these results suggest that rural wintering birds tend to move more between seasons and that, while urban and rural populations are connected, urban areas may act as a sink for rural wintering birds, supplementing the resident urban population".