Wild Bird Population Declines: Welfare Implications of Ecosystem Loss

North America has lost nearly 3 billion birds since 1970, with declining populations representing enormous ongoing welfare consequences for individual birds facing food insecurity and habitat loss.

Key Facts

North America has lost approximately 2.9 billion birds — 29% of the total — since 1970 across all habitats
Grassland birds have declined most severely, with some species losing over 70% of their population
Domestic and feral cats kill an estimated 1.3-4 billion birds annually in the US alone
Window strikes kill approximately 600 million North American birds annually
Insect declines reduce food availability for insectivorous birds, causing starvation and chick mortality
Climate change is shifting bird migration timing out of synchrony with peak food availability at breeding grounds

Welfare Considerations

Population-level bird declines represent not just ecological loss but the ongoing suffering of billions of individual birds. Food insecurity from insect decline means hungry nestlings and starving adults. Habitat loss forces birds into suboptimal territories where they face greater predation pressure, reduced shelter, and limited nesting sites. The individuals suffering these consequences — the nestling that starves, the migrant that finds no food upon arrival — are the welfare reality behind population statistics. Actions that address bird declines benefit both biodiversity and the welfare of living birds.

What You Can Do

Keep cats indoors or in secured outdoor enclosures to eliminate the largest human-caused bird mortality
Apply window collision prevention films or dots to glass that kills hundreds of millions of birds annually
Plant native species in gardens to support insect food webs that birds depend on
Reduce or eliminate pesticide use that depletes bird food supply
Support habitat restoration and agricultural reform programs that benefit grassland bird populations