Ferruginous hawks are one of the largest hawks in North America, with a wingspan that can reach up to 4.5 feet. They are found mostly in the western half of North America, especially in the Great Plains region. Their populations have declined in some areas, leading to questions about whether they are rare or endangered.
Are Ferruginous Hawks Endangered?
Ferruginous hawks are not currently listed as endangered or threatened at the federal level in the United States. However, their populations have declined in certain parts of their range, primarily due to habitat loss. For this reason, they are considered a “Species of Concern” in some states.
According to the IUCN Red List, ferruginous hawks have a conservation status of “Least Concern.” Their global population is estimated to be around 20,000 mature individuals. So while they are not considered globally rare or endangered, local populations in some areas are threatened primarily by agriculture and urbanization.
Ferruginous Hawk Population Trends
Here are some key population trends for ferruginous hawks:
- Between 1966 and 2015, the overall population declined by 30%, according to the North American Breeding Bird Survey.
- In Canada, the population size is estimated at 10,000-100,000 mature individuals and suspected to be in decline of 10-30% over ten years.
- In the United States, the population size is estimated at 20,000-49,999 mature individuals.
- Regions with significant population declines include the southern parts of Alberta, Saskatchewan, and Manitoba in Canada, and parts of the western United States.
- Causes of declines include habitat loss due to cultivation of native grasslands, urbanization, energy development, and prey declines.
So while ferruginous hawks remain relatively widespread across western North America, local populations in agricultural and developed areas have shrunk. Conservation efforts are aimed at protecting remaining native grasslands and restoring degraded habitats.
Ferruginous Hawk Habitat
Ferruginous hawks rely on open grassland habitats like prairies, plains, and shrub steppe ecosystems. They are found primarily in the following regions:
- Great Plains grasslands of the United States and Canada
- Shrub steppe deserts of the Intermountain West in the United States
- Open grasslands and deserts of northern Mexico
Within these ecosystems, ferruginous hawks nest in solitary trees, on rock outcrops, or on the ground. They prefer elevated perches with a wide view of open terrain for hunting.
Conversion of grasslands to cropland has caused habitat loss for the ferruginous hawk. They avoid nested habitats and are sensitive to disturbance near their nest sites. Habitat protection and restoration of degraded areas is important for conservation.
Ferruginous Hawk Diet
Ferruginous hawks are opportunistic hunters and eat mostly small to medium sized mammals. Their diet includes:
- Ground squirrels
- Pocket gophers
- Rabbits
- Prairie dogs
- Mice
They also eat birds, reptiles, and amphibians at times. They often hunt from perches and soar low over open terrain scanning for prey. Declines in prey populations like prairie dogs may contribute to habitat avoidance.
Ferruginous Hawk Nesting
Ferruginous hawks nest from March through July depending on their range. Nest sites include:
- Rock outcrops
- Lone trees
- Shrubs
- On the ground
- Elevated platforms
- Utility structures
Nests are large structures built of sticks, grass, bark, and other materials. Ferruginous hawks are sensitive to disturbance during nesting. Pairs may abandon nests if activity occurs within 1 km during egg laying or incubation.
Ferruginous Hawk Migration
Ferruginous hawks living in the northern parts of their range migrate south for the winter. Migration patterns include:
- Northern populations migrate as far south as northern Mexico.
- Some winter in the southern United States.
- Migration peaks in September-October and March-April.
- Males arrive at breeding sites first and depart last in fall.
Southern populations in the United States and Mexico are non-migratory or partially migratory. Migration distances vary by region and age class. Banding studies have recorded migrations up to 1,737 km.
Ferruginous Hawk Conservation
Conservation actions to protect ferruginous hawk populations include:
- Protection of grassland habitats from conversion to cropland.
- Restoration of native prairie ecosystems.
- Reintroduction of natural fire regimes.
- Limits on oil and gas development near nesting areas.
- Installation of artificial nest platforms.
- Public education campaigns.
With appropriate habitat protections and public support, ferruginous hawk populations can rebound. Their specialized habitat needs require targeted conservation action.
Ferruginous Hawk Population by State
State | Estimated Population | Population Trend |
---|---|---|
California | 100-500 | Stable |
Colorado | 5,000-10,000 | Declining |
Idaho | 1,000-5,000 | Unknown |
Montana | 5,000-20,000 | Declining |
New Mexico | 500-1,000 | Stable |
North Dakota | 500-1,000 | Stable |
Oregon | 100-500 | Declining |
South Dakota | 500-1,000 | Stable |
Texas | 100-500 | Declining |
Utah | 5,000-20,000 | Stable |
Washington | 100-500 | Declining |
Wyoming | 5,000-20,000 | Declining |
Key Takeaways
- The largest ferruginous hawk populations are found in Montana, Utah, and Wyoming.
- Many states show declining or unknown population trends indicating more research is needed.
- Targeted conservation efforts may help stabilize populations in states like Colorado, Oregon, and Washington.
Comparison of Ferruginous Hawk Populations Across Regions
Region | Population Estimate | Percentage of Global Population |
---|---|---|
United States | 15,000-35,000 | 75-80% |
Canada | 10,000-100,000 | 15-20% |
Mexico | 1,000-2,500 | 5-10% |
Key Takeaways
- The United States holds the majority of the global ferruginous hawk population.
- Canada’s population makes up around 15-20% percent of the total.
- Mexico holds a small but significant portion of the overall population.
- Conservation efforts across North America are important to protect the species.
Ferruginous Hawk Breeding Range
The ferruginous hawk breeding range covers parts of western North America. The core breeding range includes:
- Southern Canada from British Columbia to Manitoba
- Western United States from Washington to North Dakota down to Texas and New Mexico
- Isolated breeding sites in eastern Washington, Oregon, Idaho, Montana, and Wyoming
- Northern Mexico
Breeding occurs from late March to early August, varying across the range. Nests are built on cliffs, in trees, on the ground, or on elevated platforms. Habitat protection is key in breeding areas.
Key Breeding Areas
Important ferruginous hawk breeding locations include:
- Grasslands of southern Alberta and Saskatchewan
- Snake River Birds of Prey National Conservation Area in Idaho
- Prairie regions of eastern Montana
- Desert grasslands of Utah
- Prairie dog towns in Colorado and New Mexico
- Northern Mexico grasslands
These core habitats allow breeding birds access to sufficient food sources and appropriate nesting sites. Conservation of prairie and shrub steppe ecosystems in breeding areas is crucial.
Threats to Ferruginous Hawks
Major threats contributing to ferruginous hawk declines include:
Habitat Loss
- Conversion of native grasslands to agriculture.
- Development of prairies for energy, residential and commercial use.
- Introduction of non-native plant species.
- Disruption of natural wildfire regimes.
Prey Declines
- Control and eradication of prairie dogs impact an important prey source.
- Habitat loss also affects rodent and rabbit populations.
- Disease outbreaks have reduced some prey populations periodically.
Human Disturbance
- Oil and gas development near nest sites.
- Recreational activities too close to nesting birds.
- Tree removal near nests.
- Efforts to reduce natural fire frequency.
Toxins and Pollution
- Lead bullet fragments ingested from prey.
- Rodenticides reducing prey populations.
- Oil field contaminants impacting nesting and foraging areas.
Targeted conservation action to protect habitat, limit disturbances, and reduce toxins can help address these threats.
Ferruginous Hawk Conservation Status
The conservation status of ferruginous hawks includes:
Organization | Conservation Status |
---|---|
IUCN Red List | Least Concern |
CITES | Not Evaluated |
US Fish & Wildlife Service | Species of Concern (regional) |
COSEWIC | Not at Risk |
While not globally threatened, regional declines and habitat-specific threats warrant ongoing monitoring and habitat protections for ferruginous hawk populations.
Ferruginous Hawk Identification
Ferruginous hawks can be identified by the following characteristics:
- Large, broad-winged buteo hawk
- Wingspan around 4.5 feet
- Pale undersides contrasting with dark brown back and wings
- Rusty-colored shoulders and thighs
- White base on tail with dark banding
- Smaller and lighter in color than the golden eagle
- Soars with flat wing profile
In flight, look for the large, pale hawk shape contrasted against dark wing edges. Perched birds appear very white below with rich reddish markings above. The legs extend past the tail in flight.
Ferruginous and Rough-legged Hawk Comparison
The ferruginous hawk and rough-legged hawk occupy similar ranges but can be distinguished by:
Trait | Ferruginous Hawk | Rough-legged Hawk |
---|---|---|
Size | Very large | Large |
Wingspan | Up to 4.5 ft | Up to 4 ft |
Plumage | Dark back, rusty shoulders | Dark belly band |
Range | Western North America | Northern North America |
Prey | Rodents, rabbits | Small mammals, some birds |
Nest sites | Cliffs, trees, ground | Cliffs, trees, ground |
In areas where they overlap, look for key identification clues like ferruginous hawk’s larger size, rusty color, and range to correctly ID them.
Conclusion
In conclusion, ferruginous hawks occupy an important ecological role across western North America. While not globally endangered, local populations face threats from habitat loss, human disturbance, prey declines, and pollution. Targeted conservation efforts to protect native grasslands and limit impacts near nesting sites can help support ferruginous hawk populations into the future.
Ongoing monitoring, habitat management, and public education are needed to maintain healthy ferruginous hawk numbers, especially in agricultural and developing areas. With appropriate conservation measures, these magnificent raptors can continue thriving across the western plains and grasslands.