Broad-winged hawks are medium-sized raptors found throughout much of North America. They are known for their distinctive broad, rounded wings and short, fanned tails. Broad-winged hawks are social birds that often migrate and nest in large groups. However, when it comes to hunting, they typically hunt alone instead of in cooperative groups. In this article, we’ll take a closer look at the hunting behaviors of broad-winged hawks and examine the evidence for whether or not they cooperate to hunt prey.
Broad-winged Hawk Natural History
Broad-winged hawks (Buteo platypterus) are one of North America’s smaller Buteo hawks, with adults reaching lengths of 13-17 inches and weights of 1/2 to 1 pound. Their wingspan is typically around 39 inches. Broad-winged hawks have short tails with wide, black and white bands. Their heads are relatively small and their wings are proportionately broad compared to other Buteo hawks.
Plumage is highly variable but typically includes a dark brown back and upperwings contrasted with a white underside featuring brown barring. The tail often shows black bands. Light morph birds are rarer and are mostly white below with brown spotting.
Broad-winged hawks breed in deciduous and mixed forest habitats across eastern North America. They are highly migratory, with northern populations migrating in large flocks known as kettles to overwintering grounds in South America.
These hawks mainly eat small mammals, reptiles, amphibians, and sometimes insects. They hunt from perches or while soaring and will swoop down to grab prey on the ground.
Broad-Winged Hawk Hunting Habits
When it comes to hunting, broad-winged hawks are ambush predators that use speed and stealth to capture prey. Here are some key facts about how broad-winged hawks hunt:
– They primarily use short hunting flights from a perch position to swoop down on prey. This allows them to use foliage to hide their approach.
– Broad-winged hawks also hunt on the wing, spotting and diving on prey while soaring over open habitats.
– These hawks most often hunt individually for small mammals like mice, voles, chipmunks, and shrews.
– They occasionally take larger prey including snakes, lizards, frogs, smaller birds, and even bats.
– Hunting most often occurs in and around forest openings that support adequate small mammal populations.
– Perch hunting allows broad-winged hawks to conserve energy compared to longer hunting flights.
– They can turn rapidly in flight using their short, broad wings to improved capturing darting prey.
No Evidence for Cooperative Hunting
There are no confirmed accounts of broad-winged hawks working together to hunt prey cooperatively. Several lines of evidence support the conclusion that broad-winged hawks always hunt alone:
– Careful field studies do not record social hunting behaviors for this species. Broad-winged hawks are not seen coordinating attacks on prey.
– When consuming larger prey items like snakes, broad-winged hawks carry the prey back to a perch and eat alone. They do not call or feed with other hawks.
– Broad-wings lack the vocalizations and social signaling used by known cooperative hunting hawk species like Harris’s hawks.
– Similarly sized raptors like sharp-shinned hawks and Cooper’s hawks are also solitary hunters, suggesting broad-wings follow this pattern.
– Broad-winged hawks do not nest cooperatively. Nesting pairs remain solitary, unlike highly social hunters.
– Hunting habitats and perch hunting techniques make coordinated attacks difficult compared to open pursuits.
So while broad-winged hawks are highly social in migration and nesting, their ambush hunting style, solitary nesting, and lack of coordinated hunting signals indicate they always hunt alone for prey rather than in packs.
Why Don’t Broad-Winged Hawks Hunt Together?
Given that broad-winged hawks congregate in large numbers during migration and will nest in loose colonies, it may seem reasonable for them to also hunt in groups. However, there are several ecological explanations for why broad-wings do not cooperate to hunt prey:
– Their forested habitat and perch hunting tactics make coordinating attacks difficult compared to more open country hunters.
– Plenty of solitary hunting opportunities likely exist, meaning there’s no advantage to sharing prey resources.
– Primary prey like mice and voles occur in sufficient densities that group hunting offers no advantage.
– Broad-wings lack physical adaptations like hovering flight needed for coordinated pack attacks.
– They have limited vocal communication skills compared to more social species. This limits their ability to coordinate attacks.
– Nesting pairs and families remain solitary and defend individual territories rather than communally nesting.
– Broad-wings may have evolved from solitary ancestors while other hawks evolved group behaviors.
So while cooperative hunting does benefit some species, the ecological, evolutionary, and behavioral traits of broad-winged hawks suggest they can thrive as solitary hunters without the need for group coordination to capture prey.
Other Raptors That Do Hunt Cooperatively
While broad-winged hawks always hunt alone, there are several species of raptors that do show cooperative hunting behaviors, including:
Harris’s Hawks: These open country hunters of the desert Southwest are well known to coordinate and surround prey. Young hawks learn this behavior by observing elders.
Galapagos Hawks: A social island species that will join together and attack seabird colonies cooperatively. Their social hierarchy helps coordinate the group.
African Crowned Eagles: Pairs may cooperate to attack monkeys and other large prey together. This increases hunting success rates.
Booted Eagles: There is some evidence that booted eagles in Asia may join up to hunt certain large bird prey cooperatively, although this is not well documented.
These cooperative hunters employ vocal communication, social learning, and coordinated attacks thanks to living in open habitats suitable to group hunting. This sets them apart from the more solitary forest broad-winged hawks.
Conclusion
In conclusion, while broad-winged hawks congregate socially in large numbers during migration and nest semi-colonially, current evidence indicates they always hunt alone for small prey. Cases of cooperative hunting in this species are lacking compared to raptors like Harris’s hawks. Ecological factors like solitary nesting, forested habitats, and a lack of social communication have likely led broad-wings to evolve as solitary hunters. Their ambush hunting style allows them to effectively capture sufficient prey without needing to hunt cooperatively in packs like some other raptors. So next time you observe a broad-winged hawk patrolling the forests, look for it stealthily sweeping down on prey using its own solitary hunting skills.