The Rufous Hummingbird (Selasphorus rufus) is a small, fast-flying hummingbird that breeds in western North America. Adult male Rufous Hummingbirds have vibrant reddish-orange plumage on their backs and flanks, with a bright iridescent orange-red throat patch. Females and juvenile birds, however, have greenish upperparts and whitish underparts with fine dark streaks, making them much less colorful than the adult males.
Identifying Features of Juvenile Rufous Hummingbirds
There are several key features that can help identify a young Rufous Hummingbird:
- Greenish upperparts – The back and crown of a juvenile Rufous is greenish in color, compared to the reddish-orange back of an adult male.
- Pale underparts – The throat and belly are whitish or pale gray, without any reddish-orange patches. Some faint dark streaking may be present on the sides.
- Dark tail – Juveniles have a mostly dark tail with white corners, lacking the broad rufous band seen on adult tails.
- Small size – They are tiny birds, measuring about 3 inches long with a wingspan around 4 inches.
- Fast, erratic flight – Like all hummingbirds, they beat their wings rapidly and can hover in place.
- Straight dark bill – The bill is fairly short and straight compared to other hummingbirds.
Plumage Differences Between Juveniles, Females, and Males
While juvenile plumage shares similarities with adult females, there are some subtle differences:
| Juvenile | Female | Male | |
|---|---|---|---|
| Back color | Greenish | Greenish | Rufous |
| Throat | Plain white | White with some streaks | Rufous |
| Belly | Plain white | White with heavy streaks | White |
| Tail | Mostly black | Black central feathers | Rufous outer tail |
As you can see, juvenile Rufous Hummingbirds lack any orange-red coloration and their underpart streaking is sparser than adults. After their first molt they acquire more streaking, while males will get varying amounts of rufous color on the throat and flanks.
When do Rufous Hummingbirds reach full adult plumage?
Rufous Hummingbirds molt and replace their feathers several times throughout the year. The progression from juvenile to adult plumage happens gradually:
- Juvenile plumage is retained for 2-3 months after hatching.
- In late summer/early fall, the first molt results in drab female-like plumage.
- Their first spring molt produces some rufous spotting in males.
- By their second fall, males have full adult coloring while females remain dull green and white.
So most Rufous Hummingbirds do not attain their mature adult plumage until they are over a year old. The males in particular take over a full year to transition from the green juvenile feathers to their bright rufous and orange coloring.
Geographic Variation in Plumage
The plumage of juvenile Rufous Hummingbirds can vary slightly across different parts of their breeding range:
Pacific Northwest
In the Pacific Northwest, birds tend to be darker overall with heavier streaking below. The tail may appear almost solid black.
California and Southwest
Farther south in California and the desert southwest, the plumage has a paler, greener cast. Streaking on the underparts is sparser and the tail has more white corners.
Alaska
In Alaska, juveniles are darker on the tail and back, with green hues mixed with dusky gray feathers. Throat streaking is also denser than other regions.
These regional variations point to some genetic differences across various breeding populations of Rufous Hummingbirds. But the overall appearance remains quite similar and all juveniles can be readily identified by their lack of bright male-like plumage.
When and Where to See Juvenile Rufous Hummingbirds
The best opportunities to observe juvenile Rufous Hummingbirds are:
- Late summer – Recently fledged young start appearing in July and August.
- Autumn migration – Juveniles make up a large portion of the birds moving south in August-September.
- Hummingbird feeders – Feeders attract and concentrate hummingbirds, making it easier to compare juveniles and adults.
- West Coast – They occur through the Pacific Coast region and western mountain ranges.
Pay attention to any small, actively feeding hummingbirds at late summer flowers and backyard feeders. If they lack bright orange coloring, they are likely juveniles. With a decent view, the mostly green and white plumage provides a clear identification clue for young Rufous Hummingbirds.
Unique Behaviors of Juvenile Rufous Hummingbirds
In addition to different plumage, juvenile Rufous Hummingbirds can display some behaviors characteristic of their young age:
- Clumsy flight – Young birds are still mastering the complexities of hovering and flying backwards.
- Less territorial – They avoid adult males and may be chased from feeders.
- Curiosity – Juveniles explore new sites and food sources.
- Constant begging calls – Loud repetitive chipping while chasing adult females.
- Quick to flee – Immature birds are skittish and quick to retreat.
These behaviors reflect the fact that juvenile hummingbirds are still naive, developing their flying skills, and dependent on adults for food. Gaining flight experience and foraging independence are vital steps for their survival and future breeding success.
Conclusion
In summary, juvenile Rufous Hummingbirds can be identified by their overall greenish plumage, lack of any orange-red throat or rufous back feathers, mostly dark tail, and pale white underparts with sparse streaking. Males take over a year to attain full colorful adult plumage. Juveniles are most likely to be observed in late summer and during fall migration. Their awkward flight and constant vocalizations are other clues indicating a young bird. Understanding the appearance and behavior of juvenile Rufous Hummingbirds provides deeper insight into this species’ life cycle and development.
