From 9-foot tall ostriches to albatrosses with gargantuan wingspans, here are some of the biggest birds in the world.

Over 500 bird species could vanish in 100 years. Protecting habitats isn't enough. Targeted recovery efforts are crucial.

The tooth-billed pigeon is a large bird native to Samoa's rainforests, ... "The tooth-billed pigeon has some of the most limited data on their calls in the world of any bird species," said James.