Sunday, June 17, 2007

Dawn Chorus Chronologies

In the last week or so I have managed to experience the phenomenon (= darkness, tiredness, stupidity) of the Dawn Chorus in three different area of the British Isles; Kindrogan in Perthshire, Dean Castle Country Park in Ayrshire, and Sunny Hill Park in London. Although this was over a period of a week, you would still expect the dawn chorus to be later in Southern England due to the effects of latitude. The light of the dawn appears first in north-east Scotland, sweeping across the Britain and taking around one hour to reach south-west England at this time of year. It is know that photoperiod and testosterone are the two main factors controlling bird song in the Oscines. Song has the dual function of mate attraction and territorial defence. For the past five years at Kindrogan, I’ve been recording the first instances of song burst for each species at dawn and it appears to be remarkably consistent from year to year.

I decided to try it elsewhere again this year. For convenience, this happened to be the nearest suitable areas after returning from Kindrogan on the 8th. The three areas cannot really be directly compared due to several variables:
i. The Kindrogan site comprises forest edge/parkland habitat and light penetrates easily.
ii.. The site in Dean Country Park comprises a lot of Beach tree cover and therefore it is quite dark in the wood.
iii. Light pollution at the London site means it does not get as dark as it should and in fact Robins sing all night under the street lamps! (though recent research suggests this may be a strategy to counteract diurnal urban noise pollution)

Kindrogan, Perthshire 56 42N, 3 44W1
1. Robin 0307h
2. Song Thrush 0315h
3. Blackbird 0322h
4. Spotted Flycatcher 0322h
5. Wren 0336h
6. Goldcrest 0339
7. Treecreeper 0353h
8. Garden Warbler 0354h
9. Chaffinch 0355h
10. Blackcap 0356h
11. Willow Warbler 0357h

Dean Castle Country Park, Ayrshire 55 37N, 4 29W
1. Robin 0309h
2. Song Thrush 0315h
3. Blackbird 0316h
4. Wood Pigeon 0343h
5. Wren 0347h
6. Goldcrest 0355h
7. Chaffinch 0407h

Sunny Hill Park, London 51 30N, 0 3W
1. Blackbird 0322h
2. Song Thrush 0332h
3. Robin 0333h
4. Wren 0356h
5. Dunnock 0417h
6. Wood Pigeon 0424h
7. Chaffinch 0434h

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