Distinguishing between a Swainson’s hawk and a red-tailed hawk can be tricky for birders, since these two raptors have some similarities in appearance. However, there are key differences in their size, color patterns, flight styles, voices, and preferred habitats that allow an observer to confidently identify them.
Size Difference
The most noticeable difference between these two hawks is their size. Swainson’s hawks are medium-sized raptors, with adults measuring 18-22 inches in length and weighing around 2 pounds. Red-tailed hawks are larger and bulkier, with adults measuring 19-25 inches in length and weighing 2.5-3.5 pounds.
When seen flying overhead, a Swainson’s hawk will have noticeably longer and thinner wings than a red-tailed hawk. The wingspan range for Swainson’s is 46-54 inches, while red-tailed hawks have a wingspan range of 48-57 inches. So while there is some overlap, a Swainson’s hawk’s wings will appear prominently longer and more slender in flight.
Color Patterns
Adult Swainson’s hawks have distinctive color patterns that make them relatively easy to identify. Their chest and belly feathers are white with some light reddish-brown speckling. The feathers on their head, back, and upper wings range from dark brown to grayish-brown. Their flight feathers are solid black, and they have a white patch at the base of their tail feathers.
Adult red-tailed hawks are most known for their namesake reddish-brown tail feathers. The rest of their body feathers can vary from light to dark brown. Some individuals have a dark patagial mark on the leading edge of their wings. Red-tails do not have the white belly or white base of the tail seen on Swainson’s.
Juvenile Swainson’s and red-tails have more variation in their plumage. But young Swainson’s often show a white patch at the base of the tail and on the belly, hinting at their eventual adult coloration.
Flight Style
The flight style of these two hawks also differs noticeably. Swainson’s hawks have longer, narrower wings suited for speed and endurance. They are agile flyers that utilize thermal updrafts to gain altitude and then go into sustained gliding flight while migrating or hunting.
In comparison, red-tailed hawks have broader wings and engage in more active flapping flight. They do sometimes soar, but not to the extent that Swainson’s hawks do. Red-tailed hawks are well adapted for maneuvering deftly through dense habitats when hunting. Their shorter wings provide greater agility at the cost of speed and endurance.
When soaring high overhead, a Swainson’s hawk will keep its wings fairly level and utilize only slight adjustments to stay aligned in a thermal. A soaring red-tail is more likely to engage in tilting its wings frequently for turning and stability.
Voice
These hawks also sound quite different when vocalizing. Swainson’s hawks give high, whistling calls that rise or fall in pitch. Their common vocalizations include a whistled “kloo-ee” often given in flight. When agitated, they make rapid “kikikiki…” calls.
In contrast, red-tailed hawks are known for their loud, piercing screams. Their familiar voice is a raspy, hoarse screaming described as “keeeeer”. They also give shorter “kik” calls when perched. The voices of these two hawks are diagnostic and make identification straightforward if vocalizations are heard.
Habitat Preference
Swainson’s hawks and red-tailed hawks generally occupy different habitats, which can aid identification. Swainson’s hawks prefer open grasslands, agricultural areas, and prairie regions. They are most abundant in the Great Plains of North America.
Red-tailed hawks are more generalists and occupy a broader range of habitats including woodlands, deserts, pastures, wetlands, parks, and suburban areas. Red-tails adapt readily to human-altered environments.
So a Swainson’s hawk seen soaring over an open agricultural field is much more likely to be correctly identified than a red-tail in the same setting. And a red-tail perched in a forest edge is more expected than a Swainson’s hawk in that same woodland habitat.
Range and Migration
The breeding and migration ranges of these species also differ. Swainson’s hawks breed mainly in western North America from Alaska through Mexico. They migrate in large flocks and travel to wintering grounds in South America.
In contrast, most red-tailed hawk populations are year-round residents throughout much of the United States and southern Canada. Some northern red-tails migrate short distances but not to the extent of the classic long-distance migration completed by Swainson’s hawks.
So a Swainson’s is much more likely to be encountered during migration over Central America or in its South American wintering grounds. Whereas red-tailed hawks are widespread and occupy much of North America year-round.
Identification Tips
Here are some helpful identification tips to distinguish a soaring Swainson’s hawk from a red-tailed hawk:
- Swainson’s hawks have longer, thinner wings held horizontally when soaring
- Swainson’s exhibit a dihedral soaring style, tilting up their wings in a slight V-shape
- Look for white feathers on a Swainson’s belly, base of the tail, and wing linings
- Swainson’s have dark eyes that can appear hooded
- Listen for the whistling “kloo-ee” call of the Swainson’s
Tips for identifying a red-tailed hawk include:
- Broader wings held flat or in a slight dihedral
- Frequent wing flapping and tilting while soaring
- Dark patagial marks on some individuals
- Reddish-brown tail feathers (in adults)
- Listen for the piercing “keeeeer” scream
Conclusion
Telling apart a Swainson’s hawk from a red-tailed hawk is straightforward once you understand their key differences. Factors like size, wingspan, plumage patterns, flight style, voice, habitat, and geographic distribution allow confident identification of these two raptors. With practice, birders can quickly recognize a soaring Swainson’s versus a red-tail by their distinct profiles in flight.