To promote birdlife through regular feeding and hedge-laying is to keep an eye on the number of bird species affected by mankind. This in turn keeps some eye on the overall affect of man’s influence on all species.

Besides…

‘Birds are an integral part of any ecosystem they inhabit. Birds help control insects and rodents. They disperse seeds, helping to bring new life to disturbed areas. And birds are pollinators, critical for flowering plants, trees and shrubs.

When birds and their habitats are at risk, so is the wider environment. Birds depend on certain habitat conditions for survival — conditions that can be supported through balanced and sustainable forest management.’

(from Treehugger article: see this link)