Thunderbirds are legendary creatures that figure prominently in Native American mythology. The name “thunderbird” derived from the native belief that these creatures had wings so powerful they could invoked thunder. Eyewitnesses of thunderbirds in the Bridgewater Triangle describe the creature as having black feathers and a wingspan of up to 12 feet, though thunderbirds across the country have been seen with wingspans of up to 25 feet.

There have been more than a few sightings of the infamous thunderbird in the Bridgewater Triangle, the most famous one involving a cop. Police Sergeant Thomas Downey was driving home from work one very late summer night when he had a very strange encounter with a thunderbird as he slowed at an intersection. The officer claimed that a six-foot tall, winged creature was standing in the middle of the road. The creature looked at him and then darted straight up the air. As it rose up in the air and flew into woods, Downey noticed that the creature had a wingspan of 8-12 feet. This report appeared in the Boston Magazine article in 1980. Another famous Bridgewater Triangle Thunderbird legend is the “dueling thunder birds.” The story goes that two huge black birds were seen in the swamp fighting in the air. A couple of other thunderbird reports come from the book "Weird New England" written by Joseph Citro and Jeff Belanger. The book has a great chapter on the Bridgewater Triangle. One sighting in 1988 involving two young boys who followed enormous three-toed tracks into the woods only to encounter a terrifying creature with “a black wrinkled face, dark feathers and long brown legs that dangled behind it as it flew off into the forest.” The other thunderbird sighting reported in "Weird New England" occurred in 1992 in Taunton. Both of these accounts have eyewitnesses reporting the same wingspan as Thomas Downey--about 12 feet. In 1993, a mother and daughter found an enormous black bird dead in a field behind their house in Middleboro. They dragged it back to the house, wrapped its remains in aluminum foil and put it in an empty trash can. The two women had to go out. When they returned to the house they found that the evidence what they believed to be a Thunderbird was gone, already dragged off by some kind of animal. All that remained were scraps of aluminum foil littered all over the ground.