Small black Warblers that weigh (12 grams) about as much as a stack of 12 business cards fly thousands of miles across the Atlantic during their fall migration. Just imagine a journey that entails you to first pack on the pounds, and then get rid of your intestines, and to end with to forgo eating and sleeping for three days. For the blackpoll warbler, such a feat is called their fall migration. These tiny birds fly from northeastern Canada to South America every fall. But no one exactly knew what path they took. It turns out the warblers fly nonstop over the Atlantic Ocean, researchers report March 31 in the journal Biology Letters. Ecologists affixed lightweight tracking devices to five blackpoll warblers during the fall 2013 migration to discover the animals' overwater route.
The warblers fuel up on fat for the journey, going from 0.4 ounces to 0.6 ounces, some overachievers double in weight. Actually, these little meatballs with wings, and then they absorb internal organs they won't want for the trip, like their intestines, to cut excess weight. Moreover to reduce to fat, feathers, and muscle, the birds leave, taking advantage of trade winds for their journey south. The warblers can't catch these winds on their way back, so they take an overland route in the spring. Researchers aren't sure why the warblers fly south over the ocean but return over land. It could be a remnant of ancient migratory pathways, or it could actually be safer.
Furthermore flying over big land, birds have to contend with predators and collisions with anyone like buildings or cars. Migrators from birds to butterflies face a gauntlet of danger. Even though big birds that can carry extra fuel travel farther such as the Arctic tern, which hopscotches from Greenland to Antarctica and back with stops in Africa, South America, and the Arctic. This bird species is perhaps one of the most common warblers in North America. However it is also one of the fastest declining species, and researchers don't know about exact reason, why the birds are disappearing and whether the problem lies in North or South America. Researchers hope to collaborate with South American researchers to find out where these birds spend their time and what threats they’re facing. Source: National Geographic