The crows are back in downtown Portland, and there are already about 1,500 of them gathering near Pioneer Courthouse Square as the fall roost begins to take shape. Researchers tracking the birds expect that number to swell to more than 20,000 by the time winter sets in, marking the return of one of the city’s strangest annual wildlife spectacles.
Gary Granger, a certified Oregon naturalist who works with the Portland Crow Roost project, has been out following the clues the birds leave behind as the flock rebuilds downtown, according to KATU. The return of the crows each fall has become something of a seasonal signal for downtown Portland, and Granger’s group is among the researchers working to understand why the birds keep choosing the city core over quieter, rural options. Granger co-founded the citizen science initiative in late 2017 alongside physician Dr. Rebecca Provorse, and the pair regularly conduct nocturnal counts across 13 miles of gridded streets within a 400-block downtown zone, according to SciStarter.
A Population That Keeps Climbing
The scale of the roost has grown dramatically since organized counting began. In January 2024, researchers with the Portland Crow Roost project recorded a peak winter population of 22,370 roosting crows downtown, a fourfold increase since systematic counts started in late 2017, per data published by PDXScholar. Early estimates from 2013 had put the downtown flock at around 5,000 birds, making the current numbers a striking jump even by the standards of a city already known for large urban bird gatherings.
Wildlife experts at the Bird Alliance of Oregon attribute the flocking pattern to a mix of factors unique to the urban core, according to reporting by the Northwest Examiner. Those factors include the urban heat island effect, dense tree canopy, night lighting that helps deter predators like Great Horned Owls, and easy access to food waste. City microclimates retain ambient heat overnight, giving crows a warmer place to roost than the surrounding countryside.
Falconry Keeps the Flock Moving, Not Away
Because the roost brings real costs along with the spectacle, downtown business groups have leaned on non-lethal deterrents for years. Downtown Portland Clean & Safe has contracted Integrated Avian Solutions since 2017 to fly trained Harris’s hawks four to five nights a week between October and April, hazing crows out of a 72-block commercial core. The strategy isn’t meant to eliminate the birds — falconers instead nudge them toward open, grassy waterfront areas where droppings cause less property damage…