Ravens do not search for carrion by following large predators; instead, they rely on memory to find food. Studies in Yellowstone National Park have shown that these birds remember locations where wolves most frequently make kills and deliberately visit those areas. To do this, ravens are capable of traveling up to 155 kilometers a day, navigating using an internal map of the terrain.

For scavengers, finding food is challenging due to its unpredictable appearance. It was previously assumed that ravens solved this problem by following large predators and waiting for leftovers from their kills. Although birds were often observed near wolves, there was no evidence that this strategy worked over long distances or extended periods.

During a two-and-a-half-year study, GPS transmitters were attached to 69 ravens, 20 wolves from six packs, and 11 cougars. The sensors recorded over 646,000 bird movement coordinates and tens of thousands of predator movement points. Researchers also marked the exact locations of 355 ungulate carcasses killed by wolves and 137 carcasses left after cougar hunts. The ravens’ flight paths were compared with the movement trajectories of predators and the locations of carcasses.

The ravens were divided into two groups: territorial birds, which roosted within the same boundaries, and nomadic birds, which constantly changed their roosting zones. Analysis showed that ravens very rarely followed predators. Throughout the entire observation period, only one instance was recorded where a raven followed a wolf for more than an hour, after which the bird went to feed at a human landfill. No joint movements between ravens and cougars were found. The researchers noted that the GPS signal intervals might have missed short flights after wolves, but on a larger scale, the strategy of consistently following predators was not confirmed.

Instead, ravens used memory, regularly returning to areas of the park where wolves hunted most often. Comparing the routes showed that ravens flew to wolf and cougar kills as directly as they did to permanent food sources, such as garbage dumps. At a distance of 27.8 kilometers, territorial ravens deviated from a straight route by an average of 1.5 kilometers, while nomadic birds deviated by 2.5 kilometers.

The choice of predator as a food provider was also not random. Ravens fed on 48.5% of wolf kills within the first seven days after the ungulate’s death, but used only 24.8% of cougar kills. This is related to the behavioral differences of the mammals: wolves hunt in packs in open areas and howl, creating acoustic and visual cues, while cougars attack from ambush in dense forests and hide meat remains under branches or snow, making them invisible from the air.

The study results showed that searching for unpredictable food sources requires complex cognitive skills from birds. Ravens do not simply react to the presence of predators; they create a mental map of the landscape, remembering features of the terrain where wolves are most successful in hunting, and patrol these areas, relying on memory and the ability to predict resource distribution.