This is a marauding Fish Crow (Corvus ossifragus), as identified by voice, flying through a neighborhood and searching for nests to raid. If you have a lot of experience with them you can get used to picking out the slightly smaller Fish vs. American Crow as well. Whether it is tiny hatchlings or developing eggs the many nests that fill our lands, from forest to shore, are often extremely tempting targets for corvids at this point in the season. Both a male and female Baltimore Oriole were aggressively attacking this bird until it vacated the area. Groups of Fish Crow are an enormous threat to young Piping Plovers on Connecticut beaches, and we suspect they already took a couple hatchlings this year while targeting multiple busy locations. This is also why picking up ANY and ALL trash at the beach is helpful as it discourages them, and mammals, from lingering or frequenting a given area for an easy meal.
