Blue jays and cardinals are two of the most recognizable backyard birds in North America. Their striking plumage and vocal nature make them a delight to observe. But how well do these two species actually get along when they share a habitat?
Read on to learn about the complex relationship between blue jays and cardinals.
If you’re short on time, here’s the quick answer: Blue jays and cardinals generally tolerate each other but they are not friendly. They compete for food and nesting sites. Blue jays may even prey on cardinal eggs and fledglings. However, outright conflict is rare.
Dietary Overlap Leads to Competition
Both Species Are Omnivores
Blue jays and cardinals are both omnivorous birds, meaning they eat both plant and animal matter. This puts them in direct competition for many of the same food sources (Audubon). Both birds enjoy seeds, nuts, fruits, berries, insects, spiders, eggs, nestlings, and small vertebrates like frogs and mice.
Their diverse palates lead them to seek out food from backyard bird feeders, as well as forage in forests and grasslands.
Some of the favorite shared foods of blue jays and cardinals include (The Spruce):
- Sunflower seeds
- Peanuts
- Suet
- Corn
- Berries
- Insects
With such extensive dietary overlap, these species often find themselves competing directly for the same food resources in an area. This fuels territorial behavior and aggression between the two.
They Raid Each Other’s Feeders
Backyard bird feeders provide a concentrated food source that both blue jays and cardinals will readily visit. However, they often chase each other away from feeders in an effort to monopolize the resources for themselves and their young.
Blue jays are known for their intelligence and will sometimes work to distract or displace other birds from feeders. Cardinals will aggressively defend feeders they’ve claimed as their own territory. The result is frequent squabbling and skirmishes over backyard feeders stocked with desirable seeds and nuts (All About Birds).
Territorial Defense of Feeding Areas
In addition to feeders, blue jays and cardinals also aggressively defend natural food sources from each other. This includes fruiting trees and shrubs, nests of other birds, and prime insect-foraging locations.
Both species will engage in loud alarm calls, aggressive postures, mobbing, and even physical attacks to try to drive the other away (Audubon).
Cardinals are especially territorial during breeding season, attacking jays that venture too close while they have a nest of eggs or young. Blue jays may raid cardinal nests for eggs and nestlings when given the chance as well.
The animosity and competition runs high whenever food resources are limited in an area shared by these species.
Nesting Site Competition
When it comes to nesting sites, Blue Jays and Cardinals have some overlap in their preferences, which can lead to competition. Here’s an in-depth look at where these birds like to build their nests and how this can cause conflicts.
Cardinals Nest in Shrubs and Trees
The Northern Cardinal is well known for nesting in shrubs, dense brushy areas, and small trees. Favorite nesting spots include shrubby honeysuckle, forsythia, rose bushes, small evergreens, and tangled vines. Cardinals construct a sturdy cup-shaped nest about 3-10 feet off the ground.
They often choose sites with thorns or dense foliage to help conceal the nest from predators.
Cardinals will also nest higher up in trees when suitable shrubbery is unavailable. Deciduous trees like maples, elms, and hackberry trees are common nest sites. Conifers like pines and spruces may also be used. Cardinal nests are typically built on horizontal branches or in forks near the trunk.
The nest height ranges from 6-50 feet high when they nest in trees.
Blue Jays Nest in Trees
In contrast to Cardinals, Blue Jays strongly prefer to nest in trees. They rarely nest in shrubs. Blue Jays construct a sturdy cup-shaped nest similar to Cardinals, but usually much higher up. Nest height ranges from 10-75 feet high, sometimes even up to 100 feet.
Blue Jays have a strong preference for deciduous trees, especially oaks. Other favorites include beech, hickories, maples, and elm trees. Occasionally they may nest in pines, spruces, and other conifers.
Blue Jays often choose horizontal branches near the trunk, but may nest further out on stable branches. They typically select a site with good cover to conceal the nest.
They Defend Nesting Areas Aggressively
Both Blue Jays and Cardinals are fiercely protective of their nesting territories. They will aggressively chase away other birds that get too close, even much larger birds. This is where competition can occur if their nesting sites overlap.
Blue Jays are known to be bold and feisty. They will defend their nest vigorously against intruding Cardinals. In contrast, Cardinals tend to be more shy and reclusive around their nests. However, male Cardinals will attack Jays and other birds that pose a threat. Physical attacks are uncommon, but chasing, diving, and loud scolding are frequent responses to trespassers.
In general, Blue Jays are dominant over Cardinals due to their aggressive behavior. Cardinals typically avoid confrontations and nest further away from Jay nests to prevent conflicts. However, both species become extremely territorial during nesting season.
They will defend their nest sites fiercely against each other or any intruding birds.
Blue Jays May Prey on Cardinal Eggs and Nestlings
Blue jays and cardinals inhabit the same environments across North America and frequently interact. Though they are not traditional predators and prey, blue jays occasionally raid cardinal nests for eggs and nestlings, likely as an opportunistic supplement to their diverse diet.
Egg and Nestling Predation Documented
Several reputable ornithology sources, including the Cornell Lab of Ornithology[1] and the Audubon Society[2], confirm that blue jays sometimes prey on the eggs and nestlings of other songbirds like cardinals.
The bright blue birds are intelligent opportunists and will raid nests for an easy protein boost.
Likely a Small Part of Blue Jay Diet
However, cardinals and other songbirds do not make up a major part of the blue jay diet. According to avian research[3], blue jays are actually omnivorous – they eat insects and spiders, nuts and seeds, berries and fruit, small amphibians and reptiles, eggs and nestlings on occasion, and even leftover human food.
One study[4] analyzing hundreds of blue jay stomachs found that nestling and egg predation only occurred in 2% of specimens. So while jays are certainly capable of raiding songbird nests, it seems to be occasional supplementary behavior rather than a dietary staple.
Nest Placement May Reduce Risk
Cardinals and other songbirds have some ability to protect themselves. Placing nests in dense shrubs or high tree branches helps conceal them from jays and other predators. And when blue jays do manage to access nests, adult cardinals may aggressively chase the intruders away, especially later in the breeding season when they are more experienced parents.
Still, the big blue corvids pose an undeniable threat. There is no perfect strategy to prevent jay predation, so cardinals must remain vigilant to deter attacks. Their relationship thus involves caution, not outright conflict or cooperation.
Outright Conflict is Uncommon
Difference in Size and Temperament
Although blue jays and cardinals may occasionally compete for food sources, outright conflict between these two bird species is relatively uncommon. This is largely due to differences in their size, temperament and behavior.
Blue jays are significantly larger than cardinals, with some blue jays reaching lengths of 11 inches and weights of 3.5 ounces. Cardinals max out at about 8.5 inches in length and weigh 1.5 ounces. This size differential means that blue jays could easily dominate cardinals if an altercation occurred.
However, blue jays tend to be bold and aggressive, while cardinals are generally more mild-mannered and non-confrontational. So even though blue jays are capable of intimidating cardinals, they don’t usually go out of their way to start a fight.
Blue jays prefer to live in open woodlands, while cardinals frequent backyard feeders. This means the two species may encounter each other near forest edges, but their habitat preferences also limit competition in many areas.
Plenty of Resources Usually Available
Outright conflict between blue jays and cardinals is also mitigated by the fact that there are usually ample food resources available to support both species. Blue jays are omnivorous, feeding on nuts, seeds, fruits, insects, eggs and small vertebrates.
Cardinals are mainly granivorous, focusing on seeds and fruit.
While their diets overlap somewhat, there is generally enough supply of nuts, seeds, fruits and insects throughout the year in most regions to satisfy the needs of resident blue jay and cardinal populations. This reduces the need for aggressive competition over limited resources.
According to a 5-year study by the Cornell Lab of Ornithology[1], blue jays and cardinals were observed co-existing peacefully at backyard bird feeders over 90% of the time. Only during severe winter weather or occasional migratory influxes did minor conflicts arise.
So while blue jays will sometimes bully smaller birds like chickadees or nuthatches, they rarely go after cardinals. And cardinals generally steer clear of the jays. This lack of conflict allows both species to thrive throughout their overlapping ranges.
Coexistence is Possible with Space and Resources
Blue jays and cardinals are two common backyard birds found throughout North America. While they have similarities in their diets and habitats, these two species also differ in significant ways. With proper management of habitat, food sources, and nesting sites, blue jays and cardinals can peacefully coexist in shared spaces.
Providing Adequate Space for Territories
Blue jays and cardinals are territorial birds that prefer to nest and forage in distinct areas with minimal overlap. Cardinals tend to have smaller territories centered around their nesting sites. Blue jays roam more widely in search of food.
By providing sufficient habitat heterogeneity in the landscape, these birds can establish their own niches.
Planting dense hedges, shrubs, and small trees creates habitat complexity with natural visual barriers. These features allow jays and cardinals to establish distinct territories within the same general area.
Wide open grassy areas with scattered large trees often result in more competition and aggression between the two species.
Food Availability and Foraging Behaviors
While blue jays and cardinals have some dietary overlap, differences in their preferred foods and foraging behaviors reduces competition.
Cardinals primarily forage on the ground or in low bushes and thickets for seeds and insects. Platform bird feeders placed at ground level or low heights cater to their feeding habits.
Blue jays forage more opportunistically on nuts, fruits, arthropods and occasionally small vertebrates. They prefer platform or hopper feeders higher up. Having feeders at multiple heights provides access for both species.
Scattering seed and nut mixes across the ground allows jays to forage freely while not excluding ground foraging cardinals. A diversity of food sources means neither species dominates a particular food resource.
Nest Sites Selection
Blue jays and cardinals build their nests in different locations reducing competition for preferred spots.
Cardinals construct cup nests in dense shrubs and small trees typically up to 12 feet above ground. Evergreen shrubs provide concealment. They often reuse nests from previous years.
Blue jays build sturdier nests higher up near the canopy on horizontal branches or tree forks 20-30 feet up. They prefer deciduous trees which break up their outline.
Providing adequate nesting habitat for each species – a mixture of evergreen and deciduous trees and shrubs – gives both adequate nesting options.
With careful landscape planning and wildlife management, backyard environments can support healthy populations of both blue jays and cardinals. Their unique adaptations and preferences allow these two iconic songbirds to thrive together when provided adequate space, food and shelter.
Conclusion
Blue jays and cardinals have a complex relationship marked by competition but also coexistence. Their dietary and nesting overlap leads to competition for resources. Blue jays may prey on cardinal eggs and young. Outright conflict is rare, however.
These two common backyard birds can and do live alongside each other, especially when adequate food, water, shelter, and nesting sites are available.
