Northern harriers and red-tailed hawks are both medium to large birds of prey, but there are some key differences in their sizes. In this article, we will compare the lengths, wingspans, and weights of these two raptor species to help illustrate their relative sizes.
Wingspans
One of the most noticeable ways northern harriers and red-tailed hawks differ is in their wingspans. Wingspan is a measurement of the distance from the tip of one wing to the tip of the other when the bird’s wings are fully outstretched. This gives a good indication of the overall size of a bird in flight.
An adult male northern harrier has an average wingspan of around 45 inches. Females are slightly larger, averaging around 48 inches across. In comparison, red-tailed hawks are significantly bigger. Typical wingspans range from 49-57 inches for adult red-tailed hawks, with females again being larger than males on average.
To help visualize the difference, if a male northern harrier and female red-tailed hawk were flying side by side, the red-tail’s wings would stretch a foot wider across than the harrier’s. That’s a noticeable difference when seeing these birds in flight!
Lengths
Looking at body length also shows the size discrepancy between harriers and red-tailed hawks. Length is measured from the tip of the bill to the tip of the tail feathers.
Male northern harriers are about 18-20 inches long, while females measure 21-24 inches in length. Red-tailed hawks are quite a bit longer with typical body lengths of 19-25 inches for males and 23-28 inches for females.
So while the smaller male hawks are comparable in length to large female northern harriers, female red-tailed hawks can be nearly 25% longer than even the biggest harriers.
Weights
Finally, weight is another useful indicator of overall size between raptor species. Heavier birds generally have more massive, powerful builds compared to lighter weight raptors.
Species | Weight Range |
---|---|
Male Northern Harrier | 12-20 oz |
Female Northern Harrier | 24-34 oz |
Male Red-tailed Hawk | 24-46 oz |
Female Red-tailed Hawk | 35-70 oz |
As the table shows, male northern harriers weigh just 12-20 oz on average. Females are almost twice as heavy at 24-34 oz.
Red-tailed hawks are significantly heavier. Males weigh 24-46 oz, overlapping the female harrier range but averaging larger. And female red-tailed hawks are the heavyweights, ranging from 35-70 oz – more than double the weight of a male harrier!
Conclusion
When compared by wingspan, length, and weight, red-tailed hawks consistently measure larger than northern harriers.
The wingspans and lengths of female red-tailed hawks can be up to 25% greater than even the biggest female northern harriers.
And weight shows the most dramatic difference – female red-tails can weigh over twice as much as male northern harriers!
So while northern harriers are medium-sized raptors in their own right, red-tailed hawks are clearly the larger, more powerful birds of prey species when the two are compared side-by-side.
Northern Harrier vs Red-tailed Hawk: Hunting Habits
The size differences between northern harriers and red-tailed hawks are reflected in their hunting styles and prey preferences.
Northern harriers hunt primarily small mammals and birds. Typical prey includes voles, mice, rats, small rabbits and squirrels, sparrows, larks, and similar sized birds. They mainly hunt by flying low over open habitats such as marshes, fields, and prairies watching and listening for prey activity below. Their slender bodies and long wings allow them to twist and turn adeptly in pursuit of prey through tangled grasses and vegetation.
In contrast, red-tailed hawks are more likely to hunt larger mammals and birds. Common prey includes rabbits and hares, ground squirrels, prairie dogs, snakes, small rodents, as well as larger birds like pheasants, quail, grouse, and pigeons. Red-tails often scan for prey from an elevated perch. When spotting potential prey, they swoop down to strike with their powerful talons.
Habitat Preferences
Northern harriers and red-tailed hawks also differ somewhat in their habitat preferences which is linked to their hunting styles.
As mentioned above, harriers favor open areas with low vegetation that allows them to spot and pursue small prey on the ground. Grasslands, marshes, pastures, wet meadows, farmland, and prairies are prime northern harrier habitat.
While red-tailed hawks can also hunt over open habitats, they are more of a woodland and forest edge raptor. This provides the scattered trees or utility poles that red-tails prefer for elevated perching and nesting. Prime red-tailed hawk habitat includes mixed woodlands interspersed with open fields or grasslands.
Range
Both northern harriers and red-tailed hawks have widespread ranges across North America. This overlap means they can be found in many of the same regions at the same times of year.
Northern harriers breed across Canada and Alaska and throughout the lower 48 United States. They migrate south for the winter, with significant populations wintering in areas like the southern Great Plains and southeastern coastal states.
Red-tailed hawks have an even broader breeding distribution, encompassing all of North America. They are widespread year-round in the lower 48 states. Northern populations migrate southward in winter while other red-tails may migrate north from southern latitudes.
So while these raptors have some habitat differences, their ranges mean birders can find northern harriers and red-tailed hawks coinciding in many areas during spring and fall migration or wintering grounds.
Appearance: Key Field Marks
For birders wanting to identify or compare a northern harrier to a red-tailed hawk in the field, there are some excellent plumage differences to look for.
Northern Harrier
- Slender, long-winged profile in flight
- Prominent white rump patch easily seen in flight
- Female and young: Mostly brown plumage with lighter streaking below
- Male: Gray above with black wingtips; white below with black bars
- Facial discs help locate prey by sound
- Long tail extends nearly to wingtips
Red-tailed Hawk
- Broad-winged and short-tailed in flight
- Dark patagial bars on the leading edge of wings
- Light morphs: Streaked brown above, lighter below with belly band
- Dark morphs: Dark brown overall with varying rufous mottling
- Pale base of tail contrasts with darker band at tip (“red tail”)
Focusing on key characteristics like flight profile, underwing patterns, tail markings, and overall plumage can help distinguish a smaller, sleek northern harrier from a larger, bulkier red-tailed hawk.
Spotting Tips
Here are some useful tips for locating and observing northern harriers and red-tailed hawks:
Northern Harriers
- Scan over open habitats like fields, marshes, and prairies
- Watch for harriers coursing low over the ground when hunting
- Listen for the male’s owl-like “gee-gee-gee” call
- Make short “squeak” sounds to attract a harrier’s attention
- Look for them sitting on fence posts or low perches watching for prey
Red-tailed Hawks
- Watch for kettling groups soaring high on thermals
- Scan treetops and utility poles for perched individuals
- Listen for the piercing “keeeeee-aaaar” cry
- Squeak to try eliciting the red-tail’s raspy call
- Check woodland edges adjoining fields or meadows
Using the right techniques for each species’ habits and preferred habitat can improve your chances of observing northern harriers and red-tails.
When and Where to See Them
Northern Harriers
The best times and locations to spot northern harriers include:
- Fall migration – September and October
- Wintering grounds – November to February
- Early spring migration – March and April
- Large open grasslands, wetlands, or coastal marshes
- Agricultural areas like pastures, hayfields, and crop fields
Red-tailed Hawks
Ideal times and places to watch for red-tailed hawks include:
- Spring migration – March and April
- Nesting grounds – late winter through summer
- Mixed open woodlands and clearings
- Forest edges and tree lines
- Farmland with scattered trees and power poles
- Almost anywhere with sufficient prey!
Focusing efforts during peak movement periods and in the habitats each species favors will maximize sightings.
Conclusion
In comparing northern harrier and red-tailed hawk sizes, it is clear red-tailed hawks are distinctly larger in key measurements like wingspan, body length, and weight.
Their larger size gives red-tails greater speed and power to pursue larger prey typically unavailable to the slimmer, lighter harriers. Habitat preferences, hunting styles, and geographic ranges also differ between these two raptors.
But familiarity with field marks, behavior, calls, and likely sighting locations allows bird enthusiasts to readily distinguish and appreciate both northern harriers and red-tailed hawks.
Seeing a robust red-tail soaring over fields and woodlands or watching a harrier deftly coursing through marsh grasses can be memorable highlights for any birder. Gaining an understanding of their relative sizes and ecology yields a deeper appreciation of these spectacular birds of prey.