Dark Clouds over Aberystwyth
Every evening between November and February a special dark cloud fills the twilight sky over Aberystwyth pier. It’s not rain or snow in that black cloud but thousands of starlings. If you haven’t seen it yet you’re missing a real winter treat.
As evening approaches small flocks of starlings fly to the sea front. There they merge until thousands of birds wheel this way and that through the sky, like a big black beast, constantly moving and changing shape.
Their spectacular aerial dance is one of the UK’s most magnificent wildlife wonders. It’s a fascinating spectacle for children after school, at a time of year when the park’s losing its attraction. It makes a great end to days out during the Christmas and February half-term holidays.
The huge flock is called a ‘murmuration’, named for the sound of thousands of wings rippling through it. At low tide it’s possible to watch it from the jetty opposite the pier, but there’s also a good view if you stroll along the prom. Aberystwyth’s short pier helps to keep the show close to onlookers and photographers.
The starlings display confuses predators, such as peregrine falcons. According to Chris Feare, one of the UK’s leading starling experts, “when you see peregrines fly through one of these display flocks they quite rarely actually get a bird”.
Just before dark the birds stream under the pier to find their roosting places. It’s worth taking a walk by before heading off to your own roost. The sights and sounds of the chattering, jostling throng below is an unforgettable experience.
Listen out for unexpected whistles. Starlings – which are closely related to mynah birds – are excellent mimics. Not only do they imitate other birds but also humans, machines and animals, including telephones and cats.
Starlings are social birds. Roosting together helps keep them warm and safe, and it’s thought they may also share information about their feeding grounds.
The roosting behaviour of Aberystwyth’s starlings was revealed by Chris Feare and a film crew from the BBC Autumnwatch programme. Chris described his experience “There was a lot of unknown… we didn’t really know what was going to happen. …The sky was very clear, which meant we could see all the behaviour as the birds arrived and when they departed in the morning… The BBC team had cameras under the pier so that we could see what the birds were doing [during the night] using low light intensity cameras.”
Chris saw a strict pecking order, enforced with sharp bills: “we could distinguish the very glossy [mature] males from the spotty young females… there was a difference in distribution and the males had the more protected sites”. He described how “the birds started the evening nicely spaced but as the night went on they huddled together”, as he’d predicted they might. Like Antarctic penguins shuffling close to reduce heat loss, fluffed up with their heads under their wings. Thermal imaging cameras showed pockets of warmth around the birds.
As dark descended the cacophony died down. I asked Chris if the birds go to sleep. “Very definitely, yes they do” he said “there’s a little bit of calling and movement during the night, but the birds quieten down almost completely”. He adds that “some birds, it could be all birds, but we’re not really sure… are able to shut down half of their brain at a time, so they can remain alert on one side but sleep on the other.”
At dawn the starlings left the pier in waves. Chris noticed that instead of a mass exodus smaller groups of birds left at about 3 minute intervals, heading off to their feeding grounds.
The Aberystwyth starlings spend much of the day searching the Welsh countryside for grassland grubs. They stab their long bills into the soil, forcing them open to make holes. Swiveling their eyes like an owl they peer into their holes to find tasty insect larvae.
Starlings are adaptable though and will take food from bird tables if they get the chance. Kelvin Jones, the Wales’s Development Coordinator for the British Trust for Ornithology (BTO), said that in winter hungry starlings will even “pick the concentrate out of cattle feed”, making them unpopular with farmers.
Traditionally starlings were regarded as migrants heralding the onset of winter: their Welsh name, adern y eira, means snow bird. Some birds are now resident, but others are escaping the harsh winters of Northern and Eastern Europe. Kelvin Jones said “most of the birds we see in winter are coming in… some from as far away as Lithuania and Poland”.
Aberystwyth may be a winter retreat for up to 20,000 starlings, but as Chris Feare points out “the techniques for estimating numbers going in and out of roosts are not really very precise”.
Breeding bird surveys by the BTO show a startling decline in the UK resident starling population. This is probably related to changes in farming practices and insect populations. Chris Feare explained that intensively managed grassland “has far fewer invertebrates in it”. Kelvin Jones said “there’s lots of work going on into it now… we suspect it’s to do with soil invertebrates”.
As Chris Feare explained starlings “were put on the red list in 2002, on the basis that their population had declined by more than 50% in the previous 30 years” and is still declining. Kelvin Jones said that the recent BTO report [2011] shows that “the starling in Wales declined by 63%.” He adds “That’s the biggest decline of any of our widespread breeding birds in Wales”.
Synchronised Flying
Research published in 2011 by Charlotte Hemelrijk and Hanno Hildenbrandt of the University of Groningen shows that what seems like a perfectly choreographed dance works by a few simple behavioural rules. Flying at speeds of up to 22 miles an hour each starling synchronises its flight with up to seven nearest neighbours. No complicated or telepathic communication is involved in keeping the flock together as it endlessly changes shape and direction, but it’s no less wondrous for that.