Recently, wildlife biologist Pam Perry was delighted to hear a profusion of species while hiking the Mesabi Trail.
Unfortunately, she couldn't return home crowing about her discoveries. It turned out that the local corvids were pulling her leg: the nearby Blue Jays were mimicking the calls of other species, messing with her bird count.
Blue Jays are known mimics, particularly of hawks and other birds of prey. According to the Cornell Lab of Ornithology's Birds of the World, many hypotheses are considered for the behavior. For instance, some think the mimicked hawk call acts to alarm nearby birds about a nearby hawk (the "hawk is/was here" hypotheses). Others believe Blue Jays use it to trick nearby species or individuals into believing a hawk is nearby (the "deception" hypothesis).
Birds show up on radar, and their sounds and flight patterns are distinct between species.
BirdCast analyzes radar data to show you who's flying overhead during migration season - and the answers are fascinating! For instance, on May 11, 2026, over 10 million birds (including Ovenbirds, warblers, Rose-breasted Grosbeaks, and more) flew over Itasca County.
Type in your zip code or county to find out who's migrating over your area! Click here.
Less fun scientists write the call off as an accidental byproduct of an innate love of mimickry (the "idiot mimic" hypothesis), and still more hypotheses are bouncing around the ornithological brain collective (including that Blue Jays just accidentally sound like hawks, but aren't mimicking them deliberately).
According to current research available to Birds of the World, the deception hypothesis has the most support. Researchers observed a Blue Jay giving the hawk call near a crowded bird feeder, causing other birds to fly off. The Blue Jay then moved in to feed, unbothered by any competition. (If no other birds were at the feeder, the jays wouldn't bother to give the call before flying in to eat — more evidence it was using the call to manipulate the other birds.)
Another Blue Jay used the call near a feeding Boat-tailed Grackle, causing the grackle to drop the piece of bread it was eating and take cover. The Blue Jay then flew in and stole the piece of bread.
So, were the jays trying to trick Pam Perry, or did she just end up in the wrong place as they were trying to mess with nearby birds? There's no way to know, but I know which option makes me laugh.
Enjoy the whole conversation above!
For more phenology, subscribe to our Season Watch Newsletter or visit the Season Watch Facebook page.
