Allen’s Hummingbird vs Rufous Hummingbird (Selasphorus sasin vs Selasphorus rufus): The Complete Backyard Identification Guide
Quick Answer: The Fastest Way to Tell Them Apart
The hardest hummingbird pair in North America. Three honest rules:
- Adult male’s back: solid green = Allen’s; solid rufous-orange = Rufous. (Caution: some Rufous males show green on the back, so a green-backed bird is safe to call Allen’s, but check the whole bird.)
- Range and date: breeding on the California coast in spring = Allen’s; migrating through the interior West or breeding from Oregon north = Rufous.
- Females and immatures: accept the limits — they are reliably separated only in the hand or with spread-tail photos showing feather width.
At-a-Glance Comparison Table
The Selasphorus problem, side by side. KEY rows separate fastest.
| Feature | Allen’s Hummingbird | Rufous Hummingbird |
|---|---|---|
| Scientific Name | Selasphorus sasin | Selasphorus rufus |
| Length | 3.5–3.8 in (9 cm) | 3.8 in (9.5 cm) |
| Wingspan | 4.3 in (11 cm) | 4.3 in (11 cm) |
| Weight | 0.1 oz (3 g) | 0.1 oz (3 g) |
| Overall Shape | Tiny hummingbird — one of North America’s smallest birds | Tiny, famously aggressive hummingbird |
| Male Plumage KEY | Green back and crown; brilliant orange-red gorget; rufous-orange flanks, rump and tail | Almost entirely rufous-orange — back, flanks and tail — with a blazing orange-red gorget; some males show green on the back |
| Female Plumage | Green above, white below with rufous flanks and a rufous-based tail; throat whitish with dark spots | Green above, white below with rufous flanks and rufous at the tail base; throat spotted, often with an orange central patch |
| Bill Shape | Short, straight, black | Short, straight, black |
| Tail | Rufous-based with narrow outer feathers | Rufous with notched tip; broad outer feathers |
| Core Range KEY | Breeds along a narrow coastal strip of California and southern Oregon; winters in central Mexico | Breeds from the Pacific Northwest to Alaska; migrates through the Rockies and Southwest; winters in Mexico |
| Migration KEY | A remarkably early migrant — males leave California for Mexico by June and July | Long-distance migrant — the longest migration of any hummingbird relative to body size |
| Feeder Presence | Visits sugar-water feeders and flowers along the California coast during its short breeding window | The fiercest feeder bird in the West — one male will dominate and empty several feeders |
| Favorite Foods | Nectar from coastal sage and garden flowers; tiny insects | Nectar from red tubular flowers; sugar water; tiny insects |
| Song | No true song — thin chips and display sounds | No true song — chips and buzzes |
| Flight Call | A sharp, dry chip | A hard chip and a rising “tzzee” |
| Population Trend | Declining in parts of its narrow breeding range | Declining and near-threatened; a species of growing concern |
Male Field Marks, Side by Side
Allen’s Hummingbird — Male
- Green back and crown with rufous-orange flanks and tail.
- Brilliant orange-red gorget.
- On the California coast only — and only in spring and early summer.
Rufous Hummingbird — Male
- All-rufous back and sides — the orange bullet of western feeders.
- Blazing orange-red gorget.
- Chases everything, including birds ten times its size.
Female & Juvenile Marks, Side by Side
Allen’s Hummingbird — Female
- Green above with rufous flanks and a rufous-based tail.
- Essentially identical to female Rufous in the field.
- Tiny size and narrow tail feathers help, but photos and range matter more.
Rufous Hummingbird — Female
- Green back with rufous flanks and rufous at the tail base.
- Throat spots often coalesce into an orange central patch.
- Field-separable from Allen’s females only with difficulty.
Part-by-Part Anatomy Breakdown
For everything except full adult males, structure and tail shape matter more than color:
| Body Part | Allen’s Hummingbird | Rufous Hummingbird |
|---|---|---|
| Back (Adult M) | Solid green | Solid rufous-orange (some show green flecks) |
| Gorget (M) | Orange-red | Orange-red — identical in color |
| Flanks | Rufous | Rufous — identical |
| Outer Tail Feathers | Noticeably narrow | Broader |
| Female Tail Base | Rufous | Rufous — identical |
| Female Throat | Whitish, sparsely spotted | Whitish, often with an orange central patch |
| Size & Build | Slightly smaller, shorter-billed | Slightly larger, longer-billed |
Song & Call Comparison
Allen’s Hummingbird
Voice: thin, dry chips; males add a buzzy wing-trill in display.
Display: a steep dive ending in a sharp metallic whine from the tail.
Rufous Hummingbird
Voice: hard chips and a rising tzzee.
Display: a steep dive with a buzzy whine from the wings and tail.
Range & Seasonal Presence
The Allen’s Hummingbird breeds on a narrow strip of the California coast (plus southern Oregon) and winters in central Mexico; males leave by midsummer.
The Rufous Hummingbird breeds from Oregon north to Alaska — the northernmost hummingbird — and migrates through the entire West, spring along the coast and fall through the Rockies. Where both occur on the California coast in spring, adult males are separable and everything else is a challenge.
Feeder Behavior & Favorite Foods
- Allen’s Hummingbird: works coastal feeders hard during its short February–June breeding window.
- Rufous Hummingbird: the most aggressive feeder hummingbird in the West — one migrating male will dominate and empty several feeders, chasing all challengers.
- Feeder setup: the same 4:1 sugar water; during Rufous passage, hang extra feeders out of each other’s sight to spread the aggression.
- Honest reporting: in migration zones, log uncertain females as “Selasphorus sp.” — eBird accepts it, and it is the correct scientific answer.
Temperament & Flock Behavior
Allen’s Hummingbirds are feisty but short-staying — intense around the breeding strip, then gone.
Rufous Hummingbirds are legendarily pugnacious — they attack other hummingbirds, jays, and anything near the feeder, announcing themselves with hard chips and wing-buzzes.
6-Step Backyard ID Checklist
- Adult male? Green back = Allen’s; all-rufous back = Rufous.
- Male with a green-flecked back? Could be either — some Rufous show green; weigh range and date.
- Breeding season on the CA coast? Default Allen’s; north of there, default Rufous.
- Fall migrant in the Rockies? Rufous — Allen’s migrates through a narrow coastal route.
- Female or immature? Try spread-tail photos (narrow outer feathers = Allen’s) — otherwise record as Selasphorus sp.
- Voice won’t help. Their chips and buzzes are too similar for field use.
Frequently Asked Questions
- Male Back: Solid green = Allen’s; solid rufous = Rufous.
- Green-Flecked Males: Some Rufous show green — check range and date.
- Females: Field-inseparable; use photos, range, or “Selasphorus sp.”
- Breeding Map: CA/OR coastal strip = Allen’s; Oregon north to Alaska = Rufous.
- Migration: Fall interior West migrant = Rufous.
- Aggression: Both fierce; Rufous legendarily so.
