Red-shouldered Hawk vs Swainson's Hawk

In short

The most reliable field mark to separate Red-shouldered Hawk from Swainson's Hawk is the underwing pattern in flight: adult Swainson's Hawks (light morph) show a striking contrast between pale wing linings and dark flight feathers, while Red-shouldered Hawks have more evenly barred wings with translucent pale crescents near the wingtips. Juvenile Red-shouldered Hawks also show these pale crescents, while juvenile Swainson's lack them and have more mottled, less contrasting underwings. Structurally, Swainson's is significantly larger and longer-winged, with a longer tail and a slimmer, more elongated look in flight. Perched, Red-shouldered Hawks show obvious red 'shoulders' and a shorter, stockier build. Both species can show reddish tones on the chest, but the pattern and context differ. Use age-specific wing and tail patterns first, then check structure and overall jizz, especially in flight.

Identification tips

1. Underwing pattern in flight (all ages): Red-shouldered Hawks show translucent pale crescents near the wingtips, visible from below, especially in juveniles and adults. Swainson's Hawks never show these crescents; instead, light-morph adults have a sharp contrast between pale wing linings (leading edge) and dark flight feathers (trailing edge).
2. Juvenile underwing and tail: Juvenile Red-shouldered Hawks have long tails with narrow white bars and the same translucent crescents as adults. Juvenile Swainson's Hawks have a less contrasting underwing, with pale mottling in dark areas, and a less distinct subterminal tail band.
3. Adult chest and belly: Adult Red-shouldered Hawks have rich reddish barring across the chest and belly, while Swainson's Hawks (light morph) show a dark reddish 'bib' on the upper chest but a white belly and flanks. The red on Red-shouldered is more extensive and barred; on Swainson's it is more like a solid patch.
4. Head and face: Swainson's Hawk (light morph) has a noticeable white throat and face patch, contrasting with the dark bib. Red-shouldered has a brownish head with less contrast to the chest.
5. Perched 'shoulders': Red-shouldered Hawks show obvious red 'shoulders' (upper wing coverts) when perched, a feature Swainson's lacks.
6. Tail pattern: Red-shouldered's tail is long with several narrow white bars. Swainson's tail is gray-brown with about six narrow dark bands and a broader subterminal band, but lacks the crisp white barring of Red-shouldered.
7. Wing barring: Red-shouldered Hawks have heavily barred wings above and below; Swainson's wings are more uniform above and, in light morphs, show the unique pale/dark contrast below.
8. Overall structure: Swainson's Hawk is larger, longer-winged, and longer-tailed, with a rangy, slim look. Red-shouldered is more compact, with a shorter tail and wings, and appears slightly more Accipiter-like in flight.
9. Flight style: Red-shouldered Hawks flap more frequently and may appear more agile, while Swainson's Hawks soar and glide with wings in a shallow dihedral.
10. Habitat: Red-shouldered favors woodlands and riparian forests; Swainson's prefers open country, grasslands, and agricultural areas.
11. Behavior: Swainson's Hawks often perch on the ground or follow tractors and fires for insects; Red-shouldered Hawks are more arboreal and vocal.
12. Dark morph confusion: Dark-morph Swainson's are mostly dark brown with a pale undertail, but still lack the translucent crescents of Red-shouldered; they are rare in most of the Red-shouldered's range.
13. Rufous morph Swainson's: Rare and can show reddish barring, but underwing pattern and structure still separate them from Red-shouldered.
14. Size in direct comparison: If seen together, Swainson's is clearly larger and longer-winged.
15. Pitfalls: Do not rely solely on reddish tones on the chest; focus on underwing pattern, structure, and habitat for the most reliable separation.

Size

Swainson's Hawk is the larger, heavier species (average adult mass ~958.5g vs. Red-shouldered's ~625.5g). Swainson's is also longer-winged and longer-tailed, giving it a more stretched, rangy silhouette both perched and in flight. Red-shouldered Hawk is medium-sized for a Buteo, noticeably smaller and more compact than Swainson's, with a shorter tail and wings. In direct comparison, Swainson's Hawk appears bulkier and more elongated, while Red-shouldered Hawk is more compact and slightly more Accipiter-like in flight.

Plumage

Juvenile Red-shouldered Hawks (the age most often confused with Swainson's) have translucent pale crescents near the wingtips when seen from below in flight, a key mark not shown by Swainson's of any age. Their tails are long and show narrow white bars. Juvenile Swainson's Hawks have less contrast in the underwing, with pale mottling in dark areas and a less distinct subterminal tail band; their underparts are paler with some darker marks, but lack the reddish barring of adult Red-shouldered. Adult Red-shouldered Hawks show rich reddish barring on the chest and belly, dark upperparts with pale spots, and a brownish head. Their wings are heavily barred above and below, and perched birds show red 'shoulders.' Adult Swainson's Hawks (light morph) have a white underbody with a dark reddish 'bib' on the chest, a white throat and face patch, and a unique underwing pattern: pale leading edge (wing lining) and dark trailing edge (flight feathers). Their tail is gray-brown with several narrow bands and a broader subterminal band. Dark-morph Swainson's are mostly dark brown with a pale undertail, but still lack the translucent crescents of Red-shouldered. Rufous morph Swainson's are rare and show reddish barring, but the underwing pattern remains distinctive.

Behaviour

Red-shouldered Hawks often flap more rapidly and have a flight style reminiscent of Accipiters, with more frequent flapping and less steady soaring. Swainson's Hawks soar with wings held in a shallow dihedral and are more likely to be seen gliding or soaring for long periods, especially during migration. Swainson's also frequently perch on the ground, especially in open country, and may follow agricultural equipment or fires to catch insects, a behavior not typical of Red-shouldered. Red-shouldered Hawks are more likely to be seen in forested areas, often calling loudly from perches.

Habitat

Red-shouldered Hawk is primarily a bird of woodlands, especially near water, in eastern North America and along the California coast. It prefers forests, wooded swamps, and riparian corridors. Swainson's Hawk is a bird of open country: grasslands, prairies, agricultural fields, and open savannas, mostly in western and central North America. If you see a Buteo soaring over open plains or perched on a fencepost in farmland, Swainson's is much more likely; in dense woods or near streams, Red-shouldered is favored.