Winter's grip holds back rites of spring

Snowdrifts were on our minds until recently, now it's snowdrops. The delicate small white flowers peak in early February but this winter they are only now reaching full bloom in parts of Yorkshire.

It's a sign of the effects of the hard weather, but maybe not one that suggests a long-term trend. The general pattern of change is systematically measured by the UK Phrenology Network, a partnership between the Woodland Trust and the Centre for Ecology and Hydrology. They compile a Nature's Calendar survey which relies on the observations of more than 75,000 people across Britain. They report traditional indicators of spring such as the arrival of the first swallow, the appearance of the first snowdrops and first frogspawn and that comprehensive data gives a base for scientific analysis.

By comparing a list of 35 such signs in 2001 with the same springtime events last year, the survey showed that every one had been happening earlier. For example, the first rooks' nests had advanced by almost a fortnight to the last few days of February, as did the first frogspawn sightings.

The most marked change was a six-week advance on the date that the first song thrush was heard singing. The earliest in 2001 was March 19, last year it was heard on February 6. Other spring events which had been occurring much sooner included the appearance of the first red admiral butterfly (20 days early), the flowering of lesser celandine (26 days) and blackthorn (24 days), and the first cutting of lawns (22 days).

Steve Marsh of the Woodland Trust says that there may well be a blip this year because of the cold weather.

"Things have always varied from year to year. That might be especially apparent after a cold spell. However, if we look back over 30 years, the graph shows a definite advancement in the arrival of spring."

At the National Trust's Beningbrough Hall and Gardens near York, head gardener Des Cotton says the late arrival of snowdrops there is due to the bad winter. Other species late to flower include aconites, Viburnums and the Iris reticulata.

The trust has conducted a survey of how the winter has affected plants in its gardens throughout England and discovered that those in Yorkshire and Northumberland had the fewest plants showing growth. The snow and ice has also put back the growth of Yorkshire's most famous display of wild flowers, the Farndale daffodils in the North York Moors, visited by over 40,000 people each year.

The daffs spectacular usually lasts from late-March to early April, with some flowers appearing in late-February in recent years.

But the National Park's ranger for the area, David Smith, says: "The shoots are hardly coming through at the moment. So I'd say they are going to be at least a fortnight later than usual."

Their snowdrops, too, are well behind and hawthorn hedges that David normally expects to start budding in February, are still bare.

According to figures released by the Met Office this week, from the middle of December to the middle of February temperatures struggled to stay above zero, with the UK's average a chilly 1.5C (35F), making it the hardest winter since 1978-79.

The RSPB's Big Garden Birdwatch survey, held over the weekend of January 30-31, should provide a clearer picture of how those low temperatures – and the prolonged snow-cover – have affected smaller birds. The results are expected later this month.

But there are already fears that the robin – voted Britain's favourite bird in surveys – has taken a severe knock. The RSPB says the signs are that it may even drop out of the survey's 10 most seen garden birds for the first time since the nationwide birdwatch began more than 30 years ago.

Another bird causing concern is the kingfisher. In the hard winter of 1962-63 – Britain's longest cold spell of the last century – it declined by a staggering 85 per cent and took years to recover. This winter, says the RSPB, there are early signs that the UK population may have been cut in half.

Other species the RSPB predicts have suffered heavy declines are the goldcrest – Europe's smallest breeding bird – the barn owl and the stonechat.

There is also concern about the fate of England's small but growing bittern population. An extremely shy relative of the grey heron, there are perhaps fewer than 100 individuals, but from Christmas to late-January thick ice sheets covered the dense reedbeds in which they spend their time.

Supplementary feeding of the handful of bitterns at the RSPB's Old Moor reserve near Barnsley is thought to have worked. "Since the ice has melted, they seem to be alive and well at the reserve," says the RSPB's Chris Collett.

More good news is that the big freeze may have had some positive effects on nature. For example, the notorious leaf-miner moth, which climate change has brought as a new migrant to Britain from the Balkans, has for many years caused huge damage to the leaves of horse-chestnut trees, but the freezing temperatures are thought to have killed off many of the moths.

There may also be a beneficial effect on hedgehogs, which for more than a decade have failed to hibernate properly because of a succession of mild winters, and then been unable to find enough food.

Marianne Crowley, who runs a hedgehog sanctuary in Keighley, says she would normally expect to have quite a few weak hedgehogs brought to her in January and February, but this winter there have been far fewer.

"That's a sign they are hibernating properly, so fingers are crossed they will be in good condition and be able to find enough food when they do eventually emerge."

n To send reports of classic spring nature events visit www.naturescalendar.org.uk

To hear a song thrush www.rspb.org.uk/wildlife/birdguide/names/songthrush

National Trust gardens www.nationaltrust.org.uk/yorkshire