Steller’s Jays, with their striking combination of a blackish-brown head crest and deep blue body, are a common sight across the forested regions of western North America, extending from Alaska down to Nicaragua. They are large, bold, and highly inquisitive birds that thrive in coniferous forests, often adapting well to human-disturbed areas like campgrounds and backyards. Steller’s Jays are assertive and dominant birds within their local ecosystems.
Defining Aggressive Behavior
The aggression of the Steller’s Jay manifests through physical displays and vocalizations. Their presence is often announced by a loud, abrasive repertoire of calls, including a harsh, raspy squawk or a repeating “KWEK KWEK KWEK” call that acts as a general scold.
They are able to mimic the calls of raptors, specifically the scream of a Red-tailed Hawk or an Osprey. By imitating a predator, the jay can effectively scare away smaller songbirds from a food source, securing the resource for itself. Females also employ a specific “rattle call” in aggressive interactions, often used during territorial disputes or when supplanting a rival from a perch.
Physically, their aggression is visible when they confront other species. They engage in mobbing behavior, where a group of jays will harass and dive-bomb a potential predator, such as a hawk or an owl, to drive it out of the area. The jays are also opportunistic predators themselves, occasionally attacking and killing small adult birds like Dark-eyed Juncos or Pygmy Nuthatches. They are known to habitually raid the nests of other species for eggs and nestlings.
The Role of Territory and Food
The Steller’s Jay’s aggressive behavior is primarily motivated by the defense of territory and cached food. These birds maintain a social structure characterized by dominance hierarchies, where some individuals have greater access to resources than others. Pairs establish “site-centered dominance,” fiercely defending the immediate area around their nest, especially during the breeding season.
During the nesting period, the pairs become notably secretive and quiet. However, parents remain highly protective of their young, defending the territory from intruders. This territoriality extends beyond the nesting site, as jays are members of the corvid family, known for their exceptional intelligence and complex caching behavior.
Caching Behavior
Steller’s Jays are omnivores, consuming a wide range of food, and rely heavily on storing surplus items like nuts and large seeds for later consumption. They carry multiple items in their throat and mouth to bury them one at a time, using their remarkable spatial memory to retrieve them later. The aggressive acts of supplanting other birds at a resource are often directly tied to defending these valuable, cached food supplies from potential thieves.
Managing Interactions at Bird Feeders
The dominance of the Steller’s Jay is most often observed by humans at backyard feeding stations, where they can quickly monopolize the food supply. Their preference for large, calorie-dense items like whole raw peanuts, suet, and black-oil sunflower seeds makes them highly effective at emptying feeders before smaller species can access them.
One effective strategy to mitigate their dominance is to use specialized equipment, such as weight-activated feeders. Another approach is to modify the food offerings by avoiding mixes rich in their favorite items, particularly peanuts and sunflower seeds, and instead offering food types they find less appealing.
Establish a separate, designated feeding area specifically for the Steller’s Jays. By placing a platform feeder with whole, unshelled peanuts or large cracked corn away from the main feeder, their attention can be diverted. This creates a dedicated resource that allows the jays to engage in their preferred caching behavior without competing directly with smaller songbirds.