RSPB found urban sparrow colonies
waning at fastest rate where traffic-borne nitrogen dioxide was worst
Thu 2 Aug
2018 21.30 BST
The cheeky house sparrow is the
archetypal city bird. You can find them around the world, but they are in
serious decline in cities in Italy, Canada, India and the UK. London’s house
sparrow population fell by 60% between 1994 and 2006.
Scientists from
the Royal
Society for the Protection of Birds fed London sparrows in 33
colonies and compared them with birds at 33 other places where no extra food
was offered. More food meant more fledglings, but it did not improve their
wintertime survival.
The team tested for lots of
differences between the colonies that might explain this: green space, gardens,
housing density, cat populations, sparrow hawks and even electromagnetic
radiation from mobile phone signals.
Waste ground and allotments with
seed bearing plants seemed to help but the study took place between 2006 and
2009 when nitrogen
dioxide (NO2)
from traffic was increasing. This happened as diesel car
manufacturers made vehicles that passed
ever tighter legal tests in laboratories but which emitted much
more air pollution when driven on the roads.
The RSPB found that sparrow
numbers declined fastest in places with greatest nitrogen dioxide pollution in
the air. It is not just people and plants that are being affected by the state
of our urban air.
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