Several years ago I was at Gundy Lake in Charlotte County NB. I heard a strange sound. I heard the sound several times and it originated from quite a distance. As the two birds got closer I realized what was making the noise. One of the birds flew maybe 30' off the ground. The second bird flew straight up into the air maybe 150 - 200'. The second bird then dove straight down toward the first bird. The sound I was hearing all along (about 10 times before I could see it was two birds) was the sound of the diving bird pulling out of the dive. It was like the sound a Partridge makes but more rapid and louder. When I first heard the birds they were about a mile away. These birds were about the size of a barn swallow and were not any kind of raptor. The speed and rate that the bird pulled out of the dive was remarkable and generated quite an air vibration, enough so to create a loud unrecognizable sound.
Can you tell if you know what kind of bird I witnessed??
Perhaps Wilson's Snipe.
Sorry, should have continued...type Wilson's Snipe in your search engine... choose the Cornell site and listen to the 'winnowing' sound of the Snipe.