Kate Ravilious’s article (15 November) on the impact of neonicotinoid pesticides on wild insect and bird populations is welcome and frightening. But other factors should not be forgotten
One is that many of the birds living in our cool-temperate ecosystems are migrants. They are either tropical species that spend the summer here and winter in the tropics, or temperate ones that summer in the Arctic and winter here. In either case, they breed by making use of the super-abundance of insects and seeds during the northern summer
The Independent has long reported declining visits by tropical-temperate migrants to northern Europe (21 April 2008), probably due to habitat destruction and pesticide use in the tropics. An equal decline among temperate-Arctic migrants is however also predictable with the melting of tundra feeding and breeding grounds due to global warming. Since up to half of British birds visit the Arctic each year, and another fifth return to Africa, this double impact could endanger much of the bird fauna of northern Europe
Such a threat cannot be remedied by action within Europe alone. The peril of biological silence in our gardens and countryside is a reminder that our foreign and economic policies must consistently address both climate change and ecosystem preservation at global and local levels.
Dr Julian Caldecott (published in The Independent, 17 November 2010)