The world’s spectacular animal migrations are dwindling. Fishing, fences and development are fast-tracking extinctions

By Richard Fuller, Daniel Dunn, Lily Bentley, The University of Queensland

In 1875, trillions of Rocky Mountain locusts gathered and began migrating across the western United States in search of food. The enormous swarm covered an area larger than California. Three decades later, these grasshoppers were extinct.

This fate is all too common for migratory species. Their journeys can make them especially vulnerable to hunting or fishing. They may move between countries, meaning protecting the species in one jurisdiction isn’t enough. And it’s hard for us to even know if they’re in trouble.

Today, we get a global glimpse of how migratory species are faring, in the first-ever stocktake produced by the United Nations Convention on the Conservation of Migratory Species. The report shows falling populations in close to half (44%) the 1,189 species tracked by the convention. The problem is much worse underwater – 90% of migratory fish species are threatened with extinction.

Their decline is not inevitable. After all, the migratory humpback whale was headed for rapid extinction – until we stopped whaling.

Why are migratory species at higher risk?

Every year, birds weighing about 300 grams leave Siberia and fly non-stop to Australia. Some bar-tailed godwits fly 13,000 km without stopping – one of the longest known continuous migrations.

Their journeys are critical for their life cycles – to find food, mates or a better climate. To undertake these journeys, animals must be in good condition with plenty of fat stores, and they must have safe flyways, swimways and pathways.

On land, roads and fences carve up migratory routes for animals like wildebeest. At sea, fishing trawlers chase migrating schools of fish and often accidentally collect sea turtles, albatrosses and whales. On seashores, development or land reclamation take away vital resting points for migrating shorebirds.

What the report shows us is that migration between countries is getting harder and harder.

Read Full Story https://theconversation.com/the-worlds-spectacular-animal-migrations-are-dwindling-fishing-fences-and-development-are-fast-tracking-extinctions-222986