Bird populations across the world have diminished since 1970. Nearly 3 billion birds have been lost. Sparrows, blackbirds, swallows and finches have experience the greatest lost to 2.5 billion. Habitat loss is the greatest contributing factor to bird loss. Forest bird species are down 1 billion. Grassland bird species are down 50% or close to 750,000. Environmental systems and biomes are in serious jeopardy.