The Northern Cardinal is a familiar, non-migratory songbird across eastern North America, but its vibrant presence belies a constant struggle against a diverse array of predators. The male’s conspicuous red plumage and the species’ habit of building open-cup nests in exposed locations lead to significant predation pressure across all life stages. Vulnerability is pronounced from the egg and nestling phases to the adult bird. This ongoing threat influences their behavior, from alarm calls to nest placement.
Mammalian Predators: Ground and Tree Climbers
Mammals represent a significant threat to cardinals, specializing in either raiding nests or hunting adult birds. Raccoons and opossums are highly effective nocturnal nest predators. They use their agility to climb into the dense shrubs and small trees where cardinals typically build their nests. Their keen sense of smell and dexterous front paws allow them to consume eggs and nestlings. The low placement of cardinal nests, usually between one and fifteen feet off the ground, makes them easily accessible.
Squirrels, particularly Eastern Gray and Fox Squirrels, also act as opportunistic nest predators. They readily raid nests to eat eggs and young nestlings, often dismantling the structure. Eastern Chipmunks may also prey on eggs or young at accessible nest sites near the ground. The cardinal’s open-cup nest design provides little physical defense against these intruders.
Domestic and feral cats represent a major non-native threat to adult and fledgling cardinals, especially in suburban and urban environments. These skilled hunters patrol near ground level, ambushing adult birds foraging for food or recently fledged young. Cats are responsible for a high number of songbird deaths, targeting cardinals regardless of their health or age.
Avian Predators: Aerial Hunters and Nest Raiders
Avian predators pose a dual threat to cardinals: large birds of prey target adults, and smaller birds engage in nest predation. The primary aerial hunters of adult cardinals are raptors, such as the Sharp-shinned Hawk and the Cooper’s Hawk. They use swift, surprise attacks to capture cardinals in flight or while exposed at a feeder.
During the night, large owls, such as the Great Horned Owl and Eastern Screech-Owl, become a nocturnal threat. They sometimes prey on a parent sitting on the nest or roosting nearby. The strategy of these raptors focuses on speed and stealth, contrasting with the methods of corvids, the avian nest raiders.
Corvids, including the American Crow and the Blue Jay, actively search for and consume cardinal eggs and nestlings during daylight hours. They use their intelligence and observation skills to systematically check dense foliage for signs of a nest. Once located, they quickly consume the contents. Brown-headed Cowbirds also pose a threat by removing cardinal eggs to make room for their own parasitic eggs.
Reptilian and Specialized Nest Predators
Reptiles, particularly climbing snakes, are highly effective and stealthy predators of cardinal nests. Rat Snakes (Black Rat Snakes) and Black Racers are common species that ascend trees and shrubs with ease. They locate and consume entire clutches of eggs or young nestlings, often leaving little physical evidence of the predation event.
The snake’s ability to climb silently allows it to reach nests inaccessible to many mammals. Milk Snakes also raid nests, contributing to the high rate of egg and nestling loss. Nest failure is often attributed to the difficulty of defending against these climbing reptiles.
Beyond snakes, other localized threats can lead to the loss of young cardinals. Rats may occasionally climb to raid nests. Additionally, large colonies of predatory insects, such as fire ants, can overwhelm and kill helpless nestlings.