BTO - Breeding Birds of the Wider Countryside: Swallow

SWALLOW
Hirundo rustica

• Population
changes

• Productivity
trends

• Additional
information

Conservation listings

Europe: SPEC category 3 (depleted)
UK: amber (European status)

Long-term trend

UK, England: fluctuating, with no long-term trend

UK population size

726,000 territories in 2000 (1988–91 Atlas estimate updated using CBC/BBS trend: BiE04, APEP06)

Status summary

Swallow was originally amber-listed partly on the strength of a perceived CBC decline, but continues to qualify through its widespread decline across the European continent (BirdLife International 2004). Modern methods of estimating population change from CBC give evidence of fluctuations but no long-term decline in the UK (Robinson et al. 2003). Detailed analysis has shown that the population fluctuations are most strongly related to losses on their wintering grounds (Baillie & Peach 1992). More recently, population change has been shown to be correlated with rainfall in the western Sahel prior to the birds' spring passage through West Africa, but with neither cattle numbers nor nest-site availability in the UK (Robinson et al. 2003). It is likely that, in eastern parts of the UK, the loss of livestock farming and grazed grassland, together with arable intensification, has caused the Swallow population to decline, while an increase in the area of pasture in the west and north has promoted a population increase which has more than compensated for declines elsewhere (Evans & Robinson 2004). Recent BBS data suggest widespread increases in the UK since 1994, except in Scotland. Brood sizes increased up to the late 1980s, and may now be falling again. The trend towards earlier laying can be partly explained by recent climate change (Crick & Sparks 1999).

Population changes

Productivity trends

Insufficient data on CES
available for this species

Additional information


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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., 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. (2006) Breeding Birds in the Wider Countryside: their conservation status 2005. BTO Research Report No. 435. BTO, Thetford. (http://www.bto.org/birdtrends) Pages maintained by Susan Waghorn and Iain Downie: Last updated 2 May, 2006