The ferruginous hawk is a large bird of prey that lives in the open grasslands and desert regions of North America. They are opportunistic hunters that feed mainly on small mammals, birds, reptiles, and amphibians.
The ferruginous hawk (Buteo regalis) is the largest hawk species in North America. They have broad wings and a large, reddish-brown body. Their name comes from their rusty coloration on their shoulders, neck, back and upper wings.
Ferruginous hawks nest on cliffs, trees, utility poles, and the ground. They breed in the open grasslands, prairies, and desert regions of the interior West and Southwest United States and Canada. Their breeding range extends from Oregon, Montana, and North Dakota down into Arizona, New Mexico, and Texas.
These hawks migrate south to spend the winter in grasslands, agricultural areas, deserts, and scrublands ranging from the southern U.S. into Mexico. Some ferruginous hawks remain as permanent residents throughout parts of their range.
Ferruginous hawks mainly eat small to medium sized mammals but will also prey on birds, reptiles, and amphibians. Their diet varies depending on their habitat and location. These powerful raptors hunt from a perch or while soaring over open terrain.
Mammals Hunted
Mammals make up the majority of the ferruginous hawk’s diet. Over 50% of their food consists of rodents, rabbits, prairie dogs, ground squirrels, and pocket gophers. They are able to see these small prey animals moving in the grasslands from great heights.
When hunting, ferruginous hawks will survey an area from a perch or while flying high above. Once they spot potential prey, they dive down swiftly to grab the animal in their talons. Their long legs and toes are well-adapted for capturing and grasping mammalian prey on the ground.
Some of the common mammals hunted by ferruginous hawks include:
- Cottontail rabbits
- Jackrabbits
- Ground squirrels
- Prairie dogs
- Pocket gophers
- Kangaroo rats
- Pocket mice
- Woodrats
- Voles
- Mice
Rabbits and hares are a favorite prey of ferruginous hawks, especially jackrabbits which can make up 10-20% of their diet. Ground squirrels like prairie dogs are also heavily predated in areas where they are abundant.
Larger mammals are occasionally captured as well including marmots, groundhogs, muskrats, mink, weasels, skunks and rare instances of young deer, pronghorn and coyotes.
Bird Prey
Though mammals make up the bulk of their diet, birds are the second most common prey group for ferruginous hawks. They have been recorded preying on over 100 bird species, mainly smaller perching birds that live or winter in open habitats.
Some avian prey taken includes:
- Larks
- Sparrows
- Horned larks
- Meadowlarks
- Blackbirds
- Doves
- Quails
- Grouse
- Chicken
- Ducks
Ferruginous hawks will swoop down on birds from flight or ambush them from an elevated perch. They are capable of taking larger game birds like pheasants, geese, and wild turkeys on occasion. Small raptors are also preyed on infrequently including american kestrels, burrowing owls and northern harriers.
Reptiles and Amphibians
Reptiles and amphibians make up a relatively small portion of the ferruginous hawk diet. But they do opportunistically prey on lizards, snakes, frogs, toads, salamanders when the chance arises, especially during their breeding season when small prey is scarce.
Some of the herpetofauna they hunt includes:
- Horned lizards
- Western fence lizards
- Skinks
- Rattlesnakes
- Gopher snakes
- Racer snakes
- Garter snakes
- Toads
- Frogs
The broad diet of the ferruginous hawk allows it to thrive across many different habitat types throughout their range. Their tremendous eyesight and speed make them effective hunters capable of taking a variety prey on the fly or from perches.
Hunting and Feeding Behavior
Ferruginous hawks employ a wide variety hunting techniques to capture prey:
- Still-hunting: Perching and patiently waiting for prey to appear within striking distance.
- Cruising Flight: Methodically flying over an area searching for prey below.
- High Soaring: Scanning the landscape from great heights to detect prey.
- Hovering: Fluttering or suspension in air to zero in on prey.
- Low Quartering: Flying in a zigzag, low flight over terrain while looking for prey.
- Stooping: Dropping into a steep dive to strike prey.
These hawks often hunt during the early morning and late afternoon when small mammal and bird activity peaks. They will actively defend territories and vigorously chase competitors away from their hunting grounds.
Once prey is seized, ferruginous hawks will carry it to a perch or nest to feed. They tear flesh with their curved beak and shred meat with their sharp talons. Bones, fur, and feathers are discarded as pellets. They will also eat prey on the ground.
Ferruginous hawks are central place foragers during breeding season. They frequently return to the nest-site with prey to feed hungry nestlings and brooding mates. Hunting perches are established near the nest area.
In wintering areas, they become more wide-ranging opportunistic hunters feeding solitarily on prey that happens to be available over a broader territory.
Habitat
Ferruginous hawks live in open grasslands, sagebrush, deserts, and semi-arid shrublands. They avoid forested and developed areas. These habitats provide ideal hunting grounds with abundant small mammals and other prey.
Some key habitats include:
- Shortgrass and mixed-grass prairies
- Grassland plateaus
- Mountain basins
- desert scrub
- Salt flats
- Sagebrush plains
Hunting perches are an important habitat requirement. Ferruginous hawks use trees, utility poles, rocky outcrops, fence posts, mounds, and other slightly elevated sites as perches for hunting and feeding. Coastal sand dunes are used as perches by wintering ferruginous hawks.
Nesting occurs on cliffs, bluffs, trees, or utility towers generally near suitable hunting terrain. Protecting and preserving these landscapes and habitat features is crucial for conservation of the ferruginous hawk.
Threats and Conservation
While still common, ferruginous hawk numbers have declined in parts of their range. Habitat loss, degradation, and fragmentation are the main threats.
Conversion of grasslands and prairies to cropland has reduced habitat and prey availability. Tree removal and urbanization have decreased nesting sites and perches. Other issues are collisions with vehicles and wind turbines, shooting, predation, and climate change.
Various conservation measures have been implemented to aid ferruginous hawk populations:
- Protecting and restoring grassland habitats
- Installing artificial nest platforms
- Working with landowners to conserve habitat on private property
- Limiting disturbance near nest sites
- Retrofitting power poles to prevent electrocution
Thanks to conservation, some populations have recovered from previous declines. Ongoing habitat management and protection will be key for continued success of this iconic western raptor.
Conclusion
Ferruginous hawks are powerful, opportunistic predators that inhabit open habitats across western North America. They predominately prey on mammals like ground squirrels, prairie dogs, and rabbits. Birds, reptiles, and amphibians are also captured. A variety of hunting strategies are utilized, with still-hunting from an elevated perch being a preferred technique.
Though faced with some threats like habitat loss, conservation initiatives have stabilized populations in many areas. Protecting grassland ecosystems will allow ferruginous hawks to continue thriving across the western landscape. Their role as a top predator helps keep ecosystems balanced.