Hawks do consume bluebirds, reflecting the natural dynamics of the avian food web. Bluebirds, like all small songbirds, are a potential food source for various birds of prey. Predation is a constant selective pressure, influencing the behavior and habitat choices of these passerines. Not all hawks pose the same threat, as the bluebird’s ecology places it within the hunting range of specialized raptors.
Identifying the Specific Avian Predators
The primary threat to bluebirds comes from a specific group of raptors known as Accipiters. The two most common species preying on small songbirds are the Cooper’s Hawk and the smaller Sharp-shinned Hawk. These hawks are physically adapted for maneuvering within dense cover where bluebirds often forage or seek refuge.
Accipiters are characterized by their relatively short, rounded wings and long tails, which function like a rudder to facilitate rapid twisting and turning through wooded areas and suburban backyards. This morphology allows them to ambush prey with startling speed, often emerging from thick tree lines to capture birds in flight or near feeders. The Cooper’s Hawk is a particularly formidable predator, frequently targeting small- to medium-sized birds, including bluebirds, doves, and starlings.
In contrast, the larger, broad-winged hawks, or Buteos, such as the Red-tailed Hawk, are generally less of a direct threat. Buteos typically hunt by soaring high above open country or perching on exposed poles, primarily targeting mammals like rodents and rabbits. The specialized hunting style and habitat preference of Accipiters make them the most relevant avian predators regarding bluebird mortality.
Factors Contributing to Bluebird Vulnerability
The bluebird’s habitat preferences and foraging behaviors inherently increase its susceptibility to ambush predators. Eastern Bluebirds favor open, semi-wooded environments, such as orchards, fields, and suburban edges, which offer less dense canopy cover than deep forests. This preference for open space makes them easier targets for a hawk scanning from a nearby perch.
Bluebirds regularly hunt insects from exposed vantage points, such as utility wires, fence posts, or high branches. When fixed on these exposed perches or making short, low flights, they are highly visible and vulnerable to a swift, surprise attack from a hidden Accipiter. During the nesting season, adults increase their vulnerability by making frequent, predictable trips to the nest box to feed their young.
Fledglings are the most vulnerable cohort immediately after leaving the safety of the nest cavity. These young birds are inexperienced flyers, often spending their first few days on the ground or in low shrubbery while learning to forage and evade threats. This period of low mobility coincides with the Accipiters’ need to feed their own growing young, making the fledging stage a time of elevated risk.
Reducing Predation Risk Near Nesting Areas
Minimizing the risk of avian predation focuses on discouraging the hawk’s hunting success near the bluebird’s nesting sites and primary foraging areas. This requires proactive management and strategic placement of resources.
Providing Escape Cover
One of the most effective strategies is providing immediate, dense cover near the nest box or feeder location. Planting thick, thorny shrubs or brush piles within 10 to 15 feet of a nest box offers bluebirds a quick escape route from a sudden aerial attack.
Nest Box Placement and Protection
The placement of the nest box should avoid isolated trees or areas adjacent to dense woods that can serve as a hiding spot for an Accipiter. Mounting nest boxes on smooth metal poles, rather than wooden posts, deters climbing predators and helps keep the box away from wood lines. Additionally, nest box monitors can install a Noel guard, a wire mesh excluder that prevents a hawk or owl from reaching a talon through the entrance hole to snag a nestling or adult bird.
Managing Feeders
If a hawk is frequently observed hunting in a specific area, temporarily removing backyard bird feeders may encourage the raptor to move its hunting territory elsewhere. Concentrating large numbers of small birds at a feeder creates a reliable food source, essentially setting up a “hawk buffet” that attracts predators. By providing cover and ensuring feeders are not an easy target, bluebirds are given a better chance to survive a hawk’s natural hunting attempt.