Big cats and hyenas shadow the flocks, picking off stragglers. Crocodiles wait in ambush along the rivers. Vultures wheel overhead. Nature is a cruel mistress.
Few wildlife spectacles in our part of the world rank with those of the wildebeest, the caribou traversing the Arctic tundra or the storks and raptors circling in thermals before crossing the Bosporus or the Straits of Gibraltar. The gannet colonies at Saint Kilda and Little Skellig each summer come to mind but our great winter wildlife shows are staged by a more familiar, and slightly despised, bird; the humble starling.
Each evening these avian equivalents of the rat gather into gigantic flocks and wheel about the sky in wispy aerobatic displays before descending into reed-beds or woods to sleep through the night. It’s a spectacle, alas, which few people get to see but now the Royal Society for the Protection of Birds is offering guided visits to roosts in Britain.
The birds don’t necessarily choose the same locations each night, so trip organisers don’t know in advance where to go. The starling safaris, therefore, take place at dawn rather than dusk, guides having located the sites the previous evening. Participants are led to the venues in time for the starling ‘explosions’. Outings in Somerset this winter cost £6 per head, including breakfast at a local hostelry after the show.
Flocking is a starling ‘thing’; this gregarious bird breeds in loose colonies and newly fledged youngsters roam the countryside in the bird equivalent of teenage gangs. Great mimics, starlings chatter constantly among themselves but what they are saying is anybody’s guess. Like ourselves, they seek out company at meal times. Most winter feeding flocks, or murmurations, are of less than 50 birds but, in one British study, 6% had more than 250 members.
Towards nightfall, flocks head for roosting sites which may be up to 30km away. They circle as dusk approaches, attracting others from far and wide. Concentrations of more than 100,000 are common and numbers can exceed a million. The birds here in winter are mostly foreigners. Of the hundreds of starlings I ringed in the last 25 years, few travelled more than a few kilometres subsequently; the ones I manage to catch must all be locals. Although youngsters may disperse from their natal areas, Irish starlings stay here for the winter.
According to the Atlas of Breeding Birds, there were about 360,000 territories in Ireland each summer between 1988 and 1991. The numbers here in winter are impossible to estimate with any accuracy, because so many visitors fly in from Europe, nor are they constant from year to year.
Writing in the Migration Atlas, Chris Feare noted that 87,000 starlings passed through Hunstanton, Norfolk, on a single day, October 16, 1997.
Back in 1967, GR Potts, using sampling techniques, came up with a figure of 37 million wintering starlings in Britain and Ireland.
Flocks offer security to birds. Hawks and owls target them but, with so many companions around it, an individual is unlikely to become a victim. A crowd generates heat; roosting in the thick of one reduces the nightly heating bill. There is also the grapevine; by following the heavier well-fed birds after the morning explosion, a bird may stumble on richer pickings.
But why do the birds opt for such enormous concentrations? Smaller, more local, gatherings would surely offer the starlings all of the advantages of the larger groups without their having to commute so far.
It’s strange too that we humans find flocks and herds so exhilarating; for most of our history, we lived in groups of 150 or less. When this limit is exceeded, one-to-one personal relationships can no longer be established between all the members of a group and we have difficulty coping.