Earlier this year, we heard reports of "hundreds of thousands" of migratory birds were dropping dead all over the southern United States and now we know why.

There were hundreds of thousands of various migrant bird species found- from warblers, sparrows, blackbirds, bluebirds that seemingly dropped dead for no reason. The bird carcasses were found across New Mexico, but also in Colorado, Texas, and Northern Mexico.

We wrote back in September about how scientists were taking samples of some of the birds that were found and going to investigate why those birds died.

Biologists had different theories as to why the birds were dying off in such massive quantities but didn't want to give any assumptions until they were able to properly research and get results back from the necropsies.

After a few months, scientists have now released their findings as to why all the birds died.

According to Gizmodo, scientists had 170 samples of birds from across the region who had been found deceased. Scientists at the U.S. Geological Survey's National Wildlife Health Center performed necropsies on about 40 of the birds and found 80% showed signs of starvation including severely shrunken muscles, blood leakage in intestinal tracts, and kidney failure.

The other 20% of the samples weren't in adequate condition to have necropsies performed.

When the dead birds were initially falling out of the sky, people believed the record-breaking wildfire season was the cause however the necropsies found no direct evidence, things like smoke poisoning.

Now that doesn't mean the wildfires had nothing to do with the birds dying. Biologists theorize the birds died straying off their natural migration paths to avoid smoke from the wildfires.

This caused the birds to use more of their energy and stored body fat that would normally get them successfully to their next destination. Instead, the birds died partially through their journey. You can read more about the biologists' findings at Gizomodo's Earther website.

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