18 October 2023
This month a flock of 100 to 200 common grackles has been hanging out at Frick Park, chattering in the trees and swirling in a dense flock whenever they’re disturbed. This is typical fall behavior for grackles and blackbirds but I wondered why they picked the park.
According to Birds of the World, common grackles (Quiscalus quiscula) are not very territorial during the breeding season and drop all rivalry in fall and winter. On migration and at overwintering sites they prefer to roost and feed in huge flocks, sometimes mixed with other blackbirds and some robins.
Common grackles roost near plentiful food but they don’t require wild places. Urban roosts are often favored on tree-lined streets or in parks. Their fall roosts in New Jersey can contain 3,000-500,000 birds (of which grackles comprise 33%).
This flock at Patuxent in Maryland looks to be 100% grackles.
Get To Know Nature in New Jersey shows what it’s like to be in the forest with hundreds of grackles.
The huge grackle flocks probably won’t stay in southwestern PA for the winter. By December they are further south, as shown on the eBird Dec-Feb map below.
But for now we have hundreds of grackles in the trees.
(credits are in the captions; click on the captions to see the originals)