Monday, January 11, 2010

Hard Facts...


...according to the classic volume, 'Weather and Bird Behaviour' by Elkins ( 2004 ed).

In living memory our worst winters have been 1916/17, 1946/47, 1962/63, 1978/79 and 1985/86.

The winter of 62/63 was the coldest in central Britain since 1740. In this spell, the freeze was from late December until March. A high pressure system extended east to cover most of NW Europe, while an arctic airmass over the Barents sea drove intensly cold air south into Europe, then west into the UK. (Does this pattern seem familiar). Persistant easterlies and atlantic depressions, blocked by the high, gave periods of prolonged snow cover from 10 days on the south coast to 40 - 70 days in central England. Even so, this was less snowy and sunnier than in 46/47.

But here is the hard bit...

Birds that could leave did so on a massive scale with Larks, Plovers and Thrushes leaving en masse. A Redwing ringed in Warwickshire landed on a ship, only 3 days after ringing, 1000km NW of the Azores. How many didn't find ships in the middle of the Atlantic?

During the 62/63 winter 15,000 corpses were found, mostly of larger birds such as Woodpigeon and Lapwing while tits, Treecreepers and Goldcrests died unnoticed, and were only conspicuous by their absence.

During the subsequent breeding season, according to the Common Birds Census, Wren numbers were down by 78% and Mistle Thrushes by 75%. Song Thrush, Green Woodpecker, Lapwing, Pied Wagtail and Moorhen dropped by over 50%. A bird not monitored by the Common Birds Census at the time, the Grey Wagtail dropped by 80% in a 12 month period.

A positive here is that the remaining survivors can now utilise optimimun habitat and food supplies and should successfully rear good broods. It takes between 3 and 5 years to recover the original numbers.

Birds on the edge of their range can suffer tremendously such as the Dartford Warbler when 98% were killed but the New Forest population rose from only one or two pairs in '63 to 250 pairs by '74. Lets hope they benefit from global warming after this...

Get the book its a good read...

6 comments:

Brian Robson said...

Interesting reading Stewart, as bird populations were larger in the 60s, and habitat more supportive than today, lets hope Wildlife can recover quickly.

Gavin Haig said...

'The Birds of Devon' (Robert Moore 1969) states that '...during the first three months of 1963 [Cirl Bunting] was almost exterminated by the intense cold...'
Sobering stuff. I'm glad it is at last beginning to thaw a tiny bit down here.

Birding about Northumberland said...

Super reading, lets hope it gets better and nubers not to badly hit.
Michelle

Warren Baker said...

let us hope for kinder weather this spring.
It will be interesting to compare the bird numbers on my patch from last year to this.

St Ives Birds & Photo Journal said...

Luckily we have not been badly hit in West Cornwall and our small bird populations should have survived reasonably well. We are all thawed out here now and probably only had a maximum of 5 days of frozen ground and less than that of snow cover. We have got a reasonable Dartford warbler population here and hopefully they will be ok.
Weather and bird behaviour is a great book and I have re read my copy many times.

Animal said...

the book!

http://www.mediafire.com/?5x55v0zzvcj

cheers!!!