Quick Answers
The Cooper’s hawk and Northern harrier are two different species of raptors found in North America. The main differences between them are:
- Size – Cooper’s hawks are larger than Northern harriers.
- Color – Cooper’s hawks have blue-gray upperparts, while Northern harriers have gray upperparts.
- Habitat – Cooper’s hawks are forest-dwelling, while Northern harriers frequent open areas like fields, marshes, and prairies.
- Prey – Cooper’s hawks mainly eat small birds and mammals, while Northern harriers eat small mammals, birds, reptiles, and insects.
- Hunting – Cooper’s hawks hunt from perches and chase prey through foliage, while Northern harriers hunt low over open ground.
- Flight – Cooper’s hawks have short, rounded wings for maneuvering, while Northern harriers have long, narrow wings suited for soaring.
Size Difference
The size difference between Cooper’s hawks and Northern harriers is quite noticeable. Cooper’s hawks measure 13 to 20 inches in length with a wingspan of 24 to 35 inches. They weigh 7 to 24 ounces. Northern harriers measure 15 to 20 inches in length but have a much longer wingspan at 40 to 52 inches. However, they only weigh 10 to 25 ounces.
So while Northern harriers have a larger wingspan for soaring flight, Cooper’s hawks are bulkier and more powerfully built birds. The female Cooper’s hawk is significantly larger than the male. Among Northern harriers, the female is again larger than the male, but the size difference is less pronounced.
Plumage Differences
In terms of plumage, Cooper’s hawks and Northern harriers show distinct differences in coloration:
- Cooper’s hawk – Adults have blue-gray upperparts, rusty barred underparts, and reddish barring on the belly. The eyes are red. The tail has black bands.
- Northern harrier – Adults are mostly gray above and light underneath, with some brown spotting. The head has an owl-like facial disc. The tail is white with black bands.
Immature birds of both species have brown upperparts rather than gray. But the Cooper’s hawk is more heavily streaked below. Northern harriers gradually acquire the adult plumage over several seasons. The differences in plumage help distinguish the two species in flight.
Habitat Preferences
Cooper’s hawks and Northern harriers live in quite different habitats:
- Cooper’s hawks prefer forested areas including deciduous, coniferous, and mixed woodlands. They often hunt along the edges of open areas. They are frequently found in woodlots, parks, and residential areas with mature trees.
- Northern harriers are birds of open country. They favor grasslands, marshes, wetlands, prairies, savannas, fields, and other open areas with low vegetation. They are often seen flying over agricultural fields and prairies.
So while Cooper’s hawks are forest raptors, Northern harriers prefer wide open spaces. This difference in habitat preference is related to their differing hunting styles and flight capabilities.
Differences in Prey
As predators, Cooper’s hawks and Northern harriers have some overlap in the prey they take, but some differences as well:
Cooper’s Hawk | Northern Harrier |
---|---|
Mainly small birds up to quail-sized | Small mammals, small birds, reptiles, insects |
Also takes small mammals like chipmunks and squirrels | Larger range of prey items taken |
Specializes in bird hunting | More of a generalist |
A couple key differences stand out: Cooper’s hawks are bird hunting specialists, while Northern harriers will eat a larger variety of prey like small mammals, reptiles, and insects. Northern harriers are able to capture slightly larger prey due to their size and longer talons.
Hunting Strategies
These two raptors have evolved different hunting strategies and flight styles to take advantage of their preferred habitats and prey:
- Cooper’s hawks – An ambush predator. Hunts from a concealed perch, swooping out quickly to take prey by surprise. Excels at maneuvering through dense forest. Uses short, rounded wings for maximum maneuverability.
- Northern harriers – Hunts low over open ground, using outstanding eyesight to spot prey. Hovers frequently to locate prey while hunting. Glides low over fields and marshlands listening for prey. Has long, narrow wings for gliding and high aspect ratio ideal for open areas.
Cooper’s hawks rely on stealth and their short wingspan to weave through a forest setting. Northern harriers utilize their long wingspan, which allows them to scan large open areas while gliding and soaring smoothly on air currents.
Flight Style and Wings
The differing habitats and hunting strategies of Cooper’s hawks and Northern harriers means they have evolved different flight capabilities and wing shapes:
- Cooper’s hawk – Has short, broad, rounded wings good for bursts of speed and maneuverability. Allows them to dart through dense woods and avoid collisions. However, wings are not suited for extensive soaring.
- Northern harrier – Longer, narrower wings designed for gliding low over open terrain. The long wings have a high aspect ratio ideal for soaring and gliding with little flapping. Allows them to fly efficiently while hunting over fields.
Cooper’s hawks have the typical accipiter wing shape that provides excellent maneuverability in confined spaces when chasing agile prey. Northern harriers have wings more typical of open country hawks and eagles, allowing smooth soaring over large open expanses.
Range and Distribution
Both Cooper’s hawks and Northern harriers are widely distributed across North America, but there are some differences in their ranges:
- Cooper’s hawks are found throughout forested areas of the United States, Canada, and even down into parts of Mexico.
- Northern harriers occur across North America, but are rare or absent from some southwest desert areas with little vegetation.
- Northern harriers can be found as far north as central Alaska and Canada, while Cooper’s hawk distribution starts to decline farther north of about 60° latitude.
So while there is substantial overlap, Northern harriers range farther north and into more open, treeless regions than the forest-dwelling Cooper’s hawk. Cooper’s hawks have a more southerly distribution centered on the forested regions of North America.
Migration Patterns
The migration patterns of these two raptors also differ:
- Cooper’s hawks – Many populations migrate, while some remain resident year-round. Migrants travel to southern U.S states, Mexico, and Central America.
- Northern harriers – More migratory than Cooper’s hawks. Most populations migrate south of Canada for winter. Migration routes span a broad front across North America.
The more northerly distribution of Northern harriers means they are more migratory, traveling south for winter. The shorter migration distances for more southerly Cooper’s hawks allow some populations to remain year-round residents. However, the exact migration patterns of each species can vary across different regions.
Reproduction and Nesting
Cooper’s hawks and Northern harriers both nest in trees, with some differences:
- Cooper’s hawks nest high up, typically 20 to 60 feet above ground.
- Northern harriers nest closer to the ground in shorter trees, 3 to 10 feet up.
- Cooper’s hawk stick nests are up to 2 feet wide.
- Northern harrier nests are sparse bowls of sticks on vegetation clumps.
The female builds the nest in both species, but only the female incubates eggs and broods nestlings. The male provides food. Clutch sizes are similar with 3 to 6 eggs for Cooper’s hawks and 4 to 7 for Northern harriers.
So while both are tree nesters, Cooper’s hawks use larger nests placed higher up to match their forest habitat. Northern harriers nest low in shorter vegetation on open ground.
Conservation Status
Neither species is globally threatened based on their extensive distributions across North America. However some key differences exist regionally:
- Cooper’s hawk populations declined but rebounded and are now stable. They adapt well to living in proximity to humans.
- Northern harriers populations have declined more significantly due to habitat loss and pesticides. Their open country habitat has been impacted by development and agriculture.
- Cooper’s hawks are listed as Least Concern by the IUCN. Northern harriers are Near Threatened.
While Cooper’s hawks have adapted to fragmented, urbanized environments, Northern harriers are more threatened by habitat conversion and degradation across their open country ranges.
Conclusion
In summary, Cooper’s hawks and Northern harriers are medium-sized North American raptors that fill different ecological niches. Main differences include size, color, habitat preferences, hunting tactics, flight capabilities, distribution, migration patterns, and conservation status. Cooper’s hawks are forest-dwellers that chase birds with short maneuverable wings, while Northern Harriers soar over open terrain and take a variety of prey. While they overlap in places, these key distinctions demonstrate how evolution has shaped them to thrive in their particular environments as predators.