Incredible shrinking sheep
July 3rd, 2009 | by Nick |
Global warming is leading to a reduction in size of a breed of wild sheep on Hirta, St Kilda. Scientists say milder winters are helping smaller Soay sheep to survive. This goes against classic evolutionary theory which predicts that wild sheep gradually get bigger, as the stronger, larger animals survive into adulthood and reproduce. The researchers found that the local environment had a stronger effect on the animals than the evolutionary pressure to grow larger. “In the past, only the big, healthy sheep and large lambs that had piled on weight in their first summer could survive the harsh winters on Hirta,”, but now, because of climate change, there is grass available for more months of the year. This means smaller individuals are becoming increasingly commoner. 5%. Sheep have also tended to give birth to smaller lambs – a phenomenon known as “the young mum effect“. The sheep have shrunk by an average of around 5% since the study began in 1985.
Some possibly unrelated posts
Fears about the impact of last December’s severe weather, the coldest in 100 years, were unfounded. The drop in small bird populations witnessed in the 
The oldest osprey of the UK – and probably the world – has returned to her eyrie in the Scottish highlands. When she left for West Africa at the end of last summer, no one expected her to return. At 26 she’s lived 3 times longer than most female ospreys. In her life she’s laid 58 eggs and hatched 48 chicks, a massive individual contribution to the survival of ospreys in Scotland, where there are still only about 200 breeding pairs. The questions now are if her mate will return and if she is still fertile. Events can be followed on the 
The construction company currently finishing off the Shard building in London, which will be the UK’s tallest skyscraper, recently had to call the council to remove a squatter from the 72nd floor: a young fox. He was surviving on scraps left by builders. After a check-up at the Riverside Animal Centre, the fox has been released on the streets of Bermondsey, having shown the type of curiosity we associate with cats. 
Otters, water voles and fish are all benefitting from the improved quality of the UK’s waterways, now described as the cleanest since the industrial revolution. Since almost disappearing from the wild in the 1970s, otters are thriving, particularly in the south west of England, Cumbria and Northumberland. The population of water voles, highly precarious in the 1990s, is also beginning to recover. The good results of stricter pollution controls and extensive conservation work are set to continue in the new year with the introduction of new European water quality directives. 
