Quite possibly. Either grackles, or maybe starlings -- both tend to show up in groups and check out lawns.
Starling:
The starlings tend to be more methodical about their yard searches. Starlings are not a native North American bird, by the way. Several decades ago some were on display in Central Park in New York City (part of a "birds mentioned in Shakespeare" exhibit), and the starlings got loose. They were so successful in the wild that they're now one of the most common birds in North America, displacing a lot of native birds, and are a real pest in some areas. And they can travel in huge flocks:
Like pigeons, they're sometimes denounced as "rats with wings", but they have a few saving graces -- they're rather cute, and they make amusing noises. If kept as a pet, they can even learn to talk pretty well, like a mockingbird or parrot.