The British Trust for Ornithology
SWALLOW
Hirundo rustica
 Swallow © Tommy Holden
 
Conservation Listings

Table 4/Amber (25-49% Population decline)
Biodiversity Steering Group Conservation Concern List
Long term trend
UK: Fluctuations with recent shallow increase
 
Status Summary
The Amber listing of the Swallow was based on a statistical artefact that is avoided by the techniques now used with CBC data. The present CBC trend suggests that numbers are actually on the increase. Nevertheless, the species is probably not censused ideally by the CBC because of its semi-colonial habits, and some conservationists remain concerned about it. The BBS, however, also suggests that Swallow populations are currently increasing. Aspects of breeding performance have shown small contrasting changes, with slight increases in the daily nest failure rate at the egg stage in the 1980s and at the nestling stage in the 1990s. Detailed analysis has shown that population fluctuations are most strongly related to losses on their wintering grounds (Baillie & Peach 1992). The trend towards earlier laying can be partially explained by recent climate change (Crick & Sparks 1999).
 
 
Table of population changes for Swallow
Source Period
(yrs)		 Years Plots
(n)		 Change
(%)		 Lower
limit		 Upper
limit		 Alert Comment
CBC all habitats 31 1968-1999 78 21 -6 52    
  25 1974-1999 80 44 15 73    
  10 1989-1999 78 31 11 52    
  5 1994-1999 77 38 24 53    
CBC farmland 31 1968-1999 62 34 4 76    
  25 1974-1999 63 57 26 94    
  10 1989-1999 64 30 10 52    
  5 1994-1999 63 37 22 53    
BBS UK 6 1994-2000 1407 21 15 27    
BBS England 6 1994-2000 1089 15 8 21    
BBS Scotland 6 1994-2000 131 1 -16 20    
BBS Wales 6 1994-2000 125 41 17 69    
BBS N.Ireland 6 1994-2000 53 67 23 126    
The Breeding Bird Survey is jointly funded by BTO, JNCC and RSPB
 
 
Table of productivity information for Swallow
Variable Period
(yrs)		 Years Mean
annual
sample		 Trend Predicted
in first year		 Predicted
in last year		 Change Comment
Clutch size 31 1968-1999 183 Linear increase 4.49 eggs 4.61 eggs 0.12 eggs  
Brood size 31 1968-1999 297 Linear increase 4.12 chicks 4.27 chicks 0.15 chicks  
Daily failure rate (eggs) 31 1968-1999 228 Curvilinear 0.0027 nests/day 0.0022 nests/day -0.0005 nests/day  
Daily failure rate (chicks) 31 1968-1999 201 Linear increase 0.0025 nests/day 0.0052 nests/day 0.0027 nests/day  
Laying date 31 1968-1999 92 Curvilinear day 170 day 162 -8 days  
 
Insufficient data on CES
available for this species




Wider Countryside Home | BTO Home | JNCC Home

This report should be cited as:
Baillie, S.R., Crick, H.Q.P., Balmer, D.E., Beaven, L.P., Downie, I.S., Freeman, S.N., Leech, D.I., Marchant, J.H.,
Noble, D.G., Raven, M.J., Simpkin, A.P., Thewlis, R.M. and Wernham, C.V. (2002) Breeding Birds in the Wider
Countryside: their conservation status 2001. BTO Research Report No. 278. BTO, Thetford. (http://www.bto.org/birdtrends)

Terms and Conditions of use
Privacy Statement

© British Trust for Ornithology
BTO, The Nunnery, Thetford, Norfolk IP24 2PU, UK. Registered Charity Number 216652
Tel: +44 (0)1842 750050 Fax: +44 (0)1842 750030 Email:
This page last updated: 21 April, 2008

Page created by Susan Waghorn