Sparrowhawks and bird declines
Despite large amounts of funding for research on farmland bird declines, agri-environment schemes have failed deliver a recovery in bird populations. Scientific study has indicated that sparrowhawks are responsible for the decline in garden-dwelling house sparrow populations.
If this is the case, what about sparrows and other birds in the wider countryside?
Using data from BTO’s Common Birds Census scheme which ran from 1962 to 2000, this research investigated the effect of growing sparrowhawk populations on songbird population levels.
19 out of 36 songbird species show statistical evidence of an effect of sparrowhawk predation
With the exception of Great Tit, all of these species have shown population declines at the national level during the period of sparrowhawk expansion.
This suggests that the ongoing consensus that declines in terrestrial bird populations in Britain are due to changes in farming practices may be overstated, and that predation by a single raptor species undergoing a rapid population increase may have made a large contribution to such declines.
Dr Chris Bell
Christopher Paul Bell is a freelance ecological consultant with over 30 years’ experience studying bird behaviour. He holds a PhD in avian ecology from University College London.
His research interests include predator/prey interactions, and he has studied extensively the role of the Eurasian Sparrowhawk in the decline of the House Sparrow in Britain.
He has also published research into climate change and spring migration in the Yellow Wagtail.
Chris is SBS’s Scientific Advisor. More information can be found on his website.