Scientific research has indicated that long-distance migrants play a crucial role in shaping and preserving ecosystems around the world. They prey on pests, pollinate flowers, carry seeds across seas and continents.

Seventy percent of New Zealand’s forests come from seeds dispersed by birds. The Micronesian imperial pigeon alone disperses seeds across the entire Palau archipelago, over 550 islands. And with the billions of birds that fly from Europe to sub-Saharan Africa every year, millions of seeds travel too. Researchers believe this function could save many species in the face of climate change.

Migrant mortality, however, has increased significantly in recent years, due to predation, hunting, and habitat loss at stopover sites. The latest research has found that a third of the billions of birds who migrate annually no longer return.