New study shows rapid Starling evolution

Starling (Alan Price, gatehousestudio.co.uk)

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A murmuration of Starlings is one of nature’s winter spectacles. Thousands come together ahead of roosting, usually in a reedbed, where they can sleep above the water in relative safety from mammal predators. These are primarily winter visitors from Russia and northeastern Europe, and soon will be starting the eastward journey to their breeding areas.

Hundreds are currently coming into RSPB Conwy at dusk, and far larger numbers in the Cefni Valley. After feeding on fields across Anglesey, last week they gathered between the A55 and Llangefni. These are, of course, native birds that have probably been making seasonal movements across Europe for millennia. But Starlings spread across North America after just 160 were released in New York’s Central Park in 1890-91. The introduction created economic and ecological problems, and the population is now estimated to number 90 million birds.

A new study, led by Julia M. Zichello from the American Museum of Natural History, shows that while the bill length of Starlings in Europe has remained the same for more than two centuries, those in North America are now 8% longer than Starlings caught in Wales, but their bodies are 5% smaller. By contrast, the bills of Starlings living in New Zealand – where they were introduced in 1862 – are no different to those in Europe.

The authors can’t be certain what has driven the changes, but suggest a number of possibilities. Longer bills can help birds to thermoregulate, so may be an adaptation to warmer summers in North America than Eurasia. But the most likely explanation is that Starlings in America obtain half their food from outwintered dairy cattle, seeking out flaked corn in bundles of Alfalfa hay. If individuals with longer bills have better access to corn, inherited traits have been passed on by those Starlings that are most successful. Finding food in feedlots may also mean that the bill suffers less wear than when they probe the soil. The pace of evolution illustrates the challenge of forecasting the results of introducing species beyond their native range.

Sightings last week include Avocet at Flint Castle, 10 Great White Egrets at RSPB Cors Ddyga and a Mealy Redpoll at Llyn Brenig. Seven Velvet Scoters and two Surf Scoters are at Llanddulas, 40 Waxwings remain near Halkyn, 90 Whooper Swans near Llanfrothen and five Slavonian Grebes in Beddmanarch Bay.

Have your say on the future of farming
The RSPB Cymru/Welsh Ornithological Society seminars on the proposals for a Sustainable Farming Scheme arrive in North Wales this week, with all welcome to Wrexham on Tuesday and Caernarfon on Wednesday, and an online session on Thursday 29th. WOS President Iolo Williams has urged people who support nature-friendly farming "If you do only one thing for Welsh wildlife in 2024 . . . please do this." Full details are on the WOS website.

Curlews need our help
Offer your help as a volunteer to survey Curlews in the Clwydian Hills this spring, as part of the Curlew Connections Wales project designed to help the species’ recovery. The project is also seeking help in Montgomeryshire and Bannau Brycheiniog National Park. Email [email protected] for details.