Crows and ravens aren't the only black birds getting ready for Halloween. Blackbirds across North America are starting to congregate in large flocks in preparation for their fall migration.
Have a look at these frequency maps to see which species have been reported to eBird in your area in October. Knowing which species are common will help you decide what's in that big blackbird flock you're seeing. The darker the purple, the more often the species was reported in that location.
This article features data from eBird's Interactive Species Maps.
Though not a "blackbird," the European Starling is a black bird that often associates with blackbirds and forms large flocks.
Do you have multiple species that might be present in your location, but you can't tell which one is which? We have a special article about blackbird identification in our latest issue of Winter Bird Highlights. Download it here and learn how to distinguish Rusty Blackbirds, Brewer's Blackbirds, and Common Grackles where their ranges overlap.