HUNTSVILLE, Alabama - It's an unusual military bird, not native to Huntsville skies: A Bell Boeing V-22 "Osprey" tilt-rotor aircraft involved in some Redstone Arsenal testing has slowed traffic on local highways this week and even had some Bridge Street Town Centre shoppers taking pictures and asking "What is that?"

The Osprey, a blend of airplane and twin-rotor helicopter, tilts its wing and twin engines overhead, allowing for vertical or short takeoff and landing. It is used by the Navy, Marines and Air Force, but isn't currently part of the Army's fleet.

However, the Army's aviation and technology expertise at Redstone Test Center has been enlisted to help evaluate procedures and countermeasures that protect Ospreys and their crews from enemy fire.

Those tests include the use of flares, said an arsenal spokesperson, which may be why some local skywatchers have reported seeing sparks fly from a V-22 making orbits around the airfield on the north edge of the arsenal.