Avon BTO

Monday, July 21, 2008

Statistical snippets

Results from 130 tetrads (33% sample) in the breeding season show some pretty clear changes.

The bad news;- Lapwing down from 17% to 8%, Cuckoo from 26% to 3%, Willow Warbler from 67% to 35% , Marsh Tit from 10% to 3%, and Yellowhammer from 47% to 37% (though much of its key habitat has yet to be explored).

The good news; MS up from 11%-24%, CG from 2% -11%, SH from 16% to 24% , BZ 18% to 72%, PE 0%-5%, even K 30%-38%, MH 29%-52%, LB 21%-55%, HG 105-45%, CD 53%-81%, GS 19%-50%, BC 59%-85% ,GC 20%-51%, RN 0%-15% ,GR 66%-92% ,and GO 55%-87%.

These figures will change a bit with further results, especially as both cotswold and mendip areas are underrepresented, and urban and suburban areas over-represented- 60 of the tetrads are from ST57, ST58, ST67, ST68. But there are few surprises. However more difficult is to puzzle out the causes.

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