Wild Bird populations in the UK 1970-2011

Figure 1:  Populations of wild birds, 1970 to 2011.

The wild bird indicators used by the government as an index of health in at least one important component of the UK’s biodiversity have just been updated using the most recently calculated population trends. Generated by the BTO and RSPB and largely based on bird monitoring schemes organised by the BTO through its extensive volunteer network, the annual update of the indicators provides a summary of the current status of birds on farmland, woodland, along waterways and wetlands, and those using the marine environment. The black line showing the average trend of all 122 species in the indicator is relatively flat demonstrating that when viewed together, the status of common native breeding bird species in the UK seems to have changed little compared with 40 years ago. This might appear at odds with recent reports of losses of more than 40 million birds but this is not the case. In the indicators, species are treated equally whatever their abundance, so that for example declines in many rare species are not over-shadowed by increases in common species. In fact, the net loss of over 40 million birds since the mid-1960s is itself a balance between almost 90 million lost (including almost 25 million Starlings and almost 20 million House Sparrows) and over 40 million gained (including over 8 million Wrens and over 7 million Woodpigeons).

As a group, farmland species have shown the most marked declines, with the largest decreases in farmland bird populations occurring between the late seventies and the early nineties. There has been little recent change in UK woodland bird populations (again, taken as a group), with the greatest decline occurring from the late eighties until the mid-nineties. In 2011 breeding water and wetland bird populations in the UK were at around the same level as they were in 1975, although there has been a decline of 14 per cent since 2000. Seabird populations in the UK have fallen by 12 per cent since a peak in 1999; however, they remain 27 per cent higher when data collection began in 1970.

Figure 6:  Populations of wintering waterbirds, 1975-6 to 2010-11

Wintering waterbird populations in the UK

In the winter of 2010-11 the wintering waterbird index in the UK was 93 per cent higher than its 1975-6 level. The index peaked in the late nineties, and has declined since, with the smoothed index falling by 4 per cent between 2004-5 and 2009-10. There are 46 species of bird included in the wintering waterbird indicator. The populations of wildfowl and waders increased by 109% and 64% respectively since 1975-6. However, between 2004-5 and 2009-10 the smoothed indices for wildfowl and for waders showed declines of 3 per cent and 7 per cent respectively. Among wildfowl, European White-fronted Goose, Mallard, and Pochard populations have decreased since 1975-76 whereas Svalbard Light-bellied Brent Goose increased by almost 21 fold and Avocet multiplied by a factor of 41. Over the same period Ringed Plover, Purple Sandpiper, Dunlin, Redshank and Turnstone populations decreased relative to the winter of 1975-6.