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BBWC Home > Contents > Appendix > Tables of alerts and population increases from WBS
   
7.1 Tables of alerts and population increases from WBS
   
1. WBS - 25 years
2. WBS - 10 years
3. WBS - 5 years
4. WBS - 25 years - population increases of >50%
 
1. Table of alerts for WBS waterways 1977-2002
Species Period
(yrs)		 Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
Yellow Wagtail 25 21 -92 -98 -87 >50  
Little Grebe 25 17 -76 -88 -41 >50 Small sample
Reed Bunting 25 52 -63 -73 -46 >50  
Redshank 25 19 -47 -85 -14 >25 Small sample
Pied Wagtail 25 65 -41 -56 -29 >25  
Common Sandpiper 25 27 -29 -44 -15 >25  
2. Table of alerts for WBS waterways 1992-2002
Species Period
(yrs)		 Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
Yellow Wagtail 10 17 -79 -89 -66 >50 Small sample
Little Grebe 10 15 -49 -65 -30 >25 Small sample
Redshank 10 19 -39 -52 -23 >25 Small sample
 
3. Table of alerts for WBS waterways 1997-2002
Species Period
(yrs)		 Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
Yellow Wagtail 5 14 -65 -77 -51 >50 Small sample
Sand Martin 5 23 -43 -56 -25 >25  
Little Grebe 5 13 -42 -55 -29 >25 Small sample
4. Table of population increases for WBS waterways 1977-2002
Species Period
(yrs)		 Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
Mute Swan 25 44 59 10 121    
Oystercatcher 25 23 73 38 123    
Whitethroat 25 41 125 12 292    
Mallard 25 57 167 103 245    
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This report should be cited as:
Baillie, S.R., Marchant, J.H., Crick, H.Q.P., Noble, D.G., Balmer, D.E., Beaven, L.P., Coombes, R.H.,
Downie, I.S., Freeman, S.N., Joys, A.C., Leech, D.I., Raven, M.J., Robinson, R.A. and Thewlis, R.M. (2005)
Breeding Birds in the Wider Countryside: their conservation status 2004.
BTO Research Report No. 385. BTO, Thetford. (http://www.bto.org/birdtrends)

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