1a. Trends in populations of selected species (wild birds)

Summary

Figure 1a (i).  Wild bird populations: breeding farmland birds, woodland birds, waterbirds and seabirds, 1970 to 2009

 

 

Figure 1a (ii). Wild bird populations: wintering waterbirds, 1975-6 to 2009

 

 

Assessment of change in bird populations

	Long term	Since 2000	Latest year
Breeding farmland birds	1970-2009		Decreased (2009)
Breeding woodland birds	1970-2009		Decreased (2009)
Breeding water and wetland birds	1975-2009		Decreased (2009)
Breeding seabirds	1970-2009		Increased (2009)
Wintering waterbirds	1975/6-2008/9		Decreased (2008/9)

Note: In order to better capture patterns in the data, the assessment is made on the basis of smoothed data.

 

• Bird populations are considered to be a good indicator of the broad state of wildlife and countryside because they occupy a wide range of habitats and they tend to be near or at the top of the food chain. Moreover, considerable long-term data on bird populations have been collected.
• Between 1970 and 2009, populations of breeding farmland and woodland birds declined by 49 per cent and 24 per cent respectively.
• In 2009, populations of breeding seabirds were 28 per cent higher than the 1970 level. The population measure for breeding water and wetland birds was eight per cent lower than in 1975.
• Since 2000, populations of breeding farmland birds, woodland birds, water and wetland birds and seabirds, declined by 11 per cent, five per cent, 11 per cent and five per cent respectively.
• In 2008-9, the wintering waterbirds was 78 per cent higher than in 1975-6. Populations peaked in 1996-7, but there has been a decline in more recent years; the measure has fallen by nine per cent since the winter of 2000-1.

Indicator description

The indicator shows changes in the breeding population sizes of common native birds of farmland and woodland and of freshwater and marine habitats in the UK. In a separate chart it also shows changes in populations of wintering waterbirds in the UK.

The indicator is based on surveys of wild bird populations and these populations fluctuate markedly from year to year. For this reason the traffic lights are assigned on the basis of a change of more than five (rather than three) per cent over the assessment period.

Overall, populations of farmland generalist species (found on farmland and other widespread habitats) have remained broadly stable, with large increases in some such as woodpigeon (Columba palumbus). One farmland generalist, yellow wagtail (Motacilla flava), has also declined by more than 70 per cent since 1970, with no apparent change in the last year. Of the 12 farmland specialist species (restricted to or highly dependent on farmland habitats), seven have declined by at least half since 1970, with numbers of tree sparrow (Passer montanus), turtle dove (Streptopelia turtur) and grey partridge (Perdix perdix) less than 10 per cent of those present in 1970.

The breeding water and wetland bird measure has shown sharp yearly fluctuations. The index for ‘wet grassland’ birds decreased by 56 per cent, while the indices for ‘fast-flowing water’ birds and birds of reedbeds decreased by 17 per cent and five per cent respectively. The index for birds of ‘slow-flowing and standing water’ increased by 73 per cent.

The wintering waterbird measure increased steadily since the 1975-6 baseline to a peak in 1996-7. Although there has been a downward trend since then, with a nine per cent decline since the winter of 2000-1, the indicator in 2008-9 is still at 78 per cent above its 1975-6 baseline.

For the breeding woodland bird measure, as with the farmland birds, there is a contrast between the trends shown by the 12 generalist species and the 26 woodland specialists. Populations of most generalist species have generally increased with numbers of long-tailed tit (Aegithalos caudatus ) more than doubling since 1970. Whilst some woodland generalists have declined (most notably bullfinch (Pyrrhula pyrrhula) and song thrush (Turdus philomelos) by 45 per cent and 44 per cent respectively), it is the woodland specialists that have shown the most marked falls, 12 species declined by more than 50 per cent since 1970 and six species by more than 70 per cent: wood warbler (Phylloscopus sibilatrix ), willow tit (Poecile montana), tree pipit (Anthus trivialis), spotted flycatcher (Muscicapa striata), lesser redpoll (Carduelis cabaret), and lesser spotted woodpecker (Dendrocopos minor).

For the seabird measure there are highly divergent trends for the constituent species; for example, kittiwakes (Rissa tridactyla) declined by 45 per cent since 1970, and arctic skuas (Stercorarius parasiticus) although increasing between 1970 and 1985, declined by half thereafter, whereas guillemots (Uria aalge) increased by 126 per cent since 1970. Some seabirds have been affected by invasive non-native mammals such as rats and mink, though local control and eradication programmes have been successful.

Relevance

Bird populations are considered to be a good indicator of the broad state of wildlife and countryside because they occupy a wide range of habitats and they tend to be near or at the top of the food chain. Moreover, considerable long-term data on bird populations have been collected.

Background

Table 1a (i). Bird species included in the farmland birds, woodland birds, seabirds and water and wetland birds indicators.

Table 1a (ii). Bird species included in the wintering water birds indicators.

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