(Newser) – Dozens of birds fell from the sky—and at least one house cat died—Thursday afternoon on a street in Boston, and no one knows why. The Boston Globe reports a resident called animal services when she noticed her cat was seriously ill and there were birds littering the ground. She said the birds were “lethargic, trying to roll over, not able to stand up or fly.” One of the first animal rescuers on the scene describes birds "just falling right out of the sky," according to NECN. The Boston Herald reports rescuers were catching birds as they fell from trees. Up to 47 birds were affected with up to 40 of those reportedly dying. One or two cats were also reported to have died, with at least one more becoming sick.

The city is investigating, with possible explanations including environmental poisoning, intentional poisoning, or a virus. Officials are inspecting neighborhood bird feeders. All the affected birds were grackles; other birds living on the street were unaffected. No more sickened or dead birds were found Friday. The dead and sickened animals from Thursday will be tested with the results expected sometime next week. While officials don't believe humans are in any danger, WCVB reports residents are advised to keep an eye on their furry friends until the investigation is complete. (Scientists may have answer for birds' gross deformity.)

