Ruby-throated Hummingbirds are the only breeding hummingbird species found east of the Mississippi River. They are a familiar sight at backyard feeders throughout the eastern United States during the spring and summer months. While the males sport their bright metallic red throats and green plumage, the females lack the flashy plumage and can be harder to distinguish.
Size Difference
One of the most obvious ways to tell male and female Ruby-throats apart is by size. The males are smaller and more slender than the females. Here are the typical measurements:
Measurement | Male | Female |
---|---|---|
Total Length | 3 – 3.5 in | 3.5 – 4 in |
Wingspan | 3.25 – 4 in | 4 – 4.5 in |
Weight | 2 – 3 g | 3 – 4.5 g |
As you can see, the females tend to be slightly larger than the males in all dimensions. This size difference is subtle but noticeable when observing hummingbirds up close.
Plumage Differences
In addition to size, the plumage is the most strikingly different characteristic between male and female Ruby-throats. Let’s compare the colors and markings:
Body Area | Male Plumage | Female Plumage |
---|---|---|
Throat | Bright metallic red | White |
Head | Metallic green | Metallic green |
Back | Metallic green | Dull green |
Chest | Grayish white | Grayish white with some green spotting |
Belly | White | White |
Tail feathers | Dark green with white tips | Dark green with white tips |
The most striking difference is the male’s bright red throat, which the females lack. The males also tend to have more vibrant, metallic green plumage on the head and back compared to the duller green of the females.
Behavioral Differences
Male and female Ruby-throats exhibit some slightly different behaviors, especially during the breeding season. Here are some of the key differences:
- Males are much more aggressive and territorial. They will actively defend nectar sources and chase away intruders.
- Males perform elaborate courtship displays, flying high in the air and diving to impress females.
- Females alone build the nest out of plant down and spider silk.
- Only females incubate the eggs and care for the hatchlings.
- Males spend more time searching for nectar; females take time to rest and replenish energy for egg-laying.
So during the breeding season, the males focus their energy on courtship displays, defending territory, and feeding; while the females are occupied with nesting activities and caring for the young. Outside of breeding season, male and female behavior is much more similar.
Voice Difference
Male and female Ruby-throats even sound slightly different! The best way to distinguish between the two is to listen for these differences in their vocalizations:
Sound | Male Voice | Female Voice |
---|---|---|
Call note | A high-pitched, rapid chi-chi-chi | A lower-pitched chi |
Courtship sounds | Chips, whistles, buzzes | No courtship sounds |
Angry chattering | Faster, more urgent | Slower, less frequent |
The male’s voice and vocalizations tend to be higher-pitched, faster, and more complex than the female’s. Being able to distinguish their voices takes practice, but can be helpful for identification.
When Gender Differences Are Most Pronounced
The differences between male and female Ruby-throats are most noticeable during the peak breeding season, which occurs in spring and early summer across their range. Here are some reasons why:
- Males are actively courting females with displays and vocalizations
- Males are aggressively guarding nectar sources and chasing intruders
- Females are busy with nesting activities
- The males’ bright red throat patches are at their peak brilliance
- The size difference between slimmer males and plumper females preparing to lay eggs is more apparent
During the non-breeding season in late summer and fall, the behaviors of the sexes are much more similar. Males are no longer courting or defending territories, their plumage is drabber, and the females are no longer weighed down with eggs. So the differences are much more subtle outside of spring and early summer.
Immature Birds
Identifying the sex of young, immature Ruby-throats can be tricky for beginners. Immatures of both sexes lack the bright red throat patch and have duller green plumage compared to adult males. However, some clues can still help determine the bird’s gender:
- Females retain some spotting on chest
- Females are larger in size
- Immature male throats may show a few red feathers
- Immature male tails tend to be longer
- Immature male bodies are slimmer
These subtle differences take practice to recognize. But with experience identifying many individuals, the size, plumage, and structural differences become more apparent.
Conclusion
Telling male and female Ruby-throated Hummingbirds apart relies on small differences in size, plumage, behavior, and voice. In general:
- Males are smaller and slimmer
- Males have extensive bright red on throat
- Males exhibit courtship behavior
- Males are aggressive in defending territory
- Male voices have higher pitch and more complexity
Females, on the other hand:
- Are larger with a plumper body shape
- Lack red throat and are duller in color
- Nest build and care for young alone
- Have simpler, lower-pitched vocalizations
These differences are most pronounced during the breeding season and much subtler the rest of the year. With practice observing Ruby-throats up close, the distinctions become clearer over time.