Rufous-tailed hummingbirds (Amazilia tzacatl) are small, colorful birds found in Mexico, Central America, and parts of South America. Despite their tiny size, they are feisty and energetic. Their size and unique characteristics make them fascinating to observe and study. Here we will explore specifically the body size and dimensions of these tiny hummingbirds.
Weight
The rufous-tailed hummingbird is very lightweight, with an average weight of just 3-6 grams (0.1-0.2 oz). This makes them one of the smallest bird species in the world. For some perspective on just how tiny these birds are, a U.S. penny weighs around 2.5 grams. So a rufous-tailed hummingbird weighs only slightly more than some coins! Their lightweight structure allows them to hover and fly swiftly during feeding.
Length
From the tip of the bill to the end of the tail, rufous-tailed hummingbirds reach an average length of 7-9 cm (2.8-3.5 in). Their wingspan ranges from 8-10 cm (3.1-3.9 in) across. Again, to put that into perspective, a new pencil is about 20 cm long. So a rufous-tailed hummingbird is less than half the length of a standard pencil.
Tail
As the name suggests, one distinguishing feature of these hummingbirds is their long, rufous-colored tail. The tail accounts for about half of their tiny body length. An adult male’s tail averages 4.3 cm (1.7 in), while the female’s tail is slightly shorter on average at 3.9 cm (1.5 in). This elongated tail allows greater maneuverability during flight.
Bill
Rufous-tailed hummingbirds have medium-length bills that are straight and very slender. Their needle-like bills allow them to retrieve nectar from flowers. An adult’s bill measures approximately 2 cm (0.8 in) long. Relative to their petite bodies, their bills are fairly long compared to other hummingbird species.
| Body Part | Average Size |
|---|---|
| Weight | 3-6 g (0.1-0.2 oz) |
| Length (bill to tail) | 7-9 cm (2.8-3.5 in) |
| Wingspan | 8-10 cm (3.1-3.9 in) |
| Tail Length – Male | 4.3 cm (1.7 in) |
| Tail Length – Female | 3.9 cm (1.5 in) |
| Bill Length | 2 cm (0.8 in) |
How Their Size Compares to Other Birds
Rufous-tailed hummingbirds are tiny compared to most common backyard birds. To highlight their petite stature, here’s how they size up against a few other species:
American Robin
– Length: 25 cm (10 in)
– Wingspan: 36 cm (14 in)
– Weight: 77 g (2.7 oz)
Robins are around 3-4 times longer and over 10 times heavier than rufous-tailed hummingbirds.
Blue Jay
– Length: 22-30 cm (8.7-11.8 in)
– Wingspan: 34-43 cm (13.4-17 in)
– Weight: 70-100 g (2.5-3.5 oz)
Blue jays are approximately 3 times longer and weigh nearly 20 times more than rufous-tailed hummingbirds.
Mourning Dove
– Length: 23-34 cm (9-13.4 in)
– Wingspan: 37-45 cm (14.6-17.7 in)
– Weight: 86-170 g (3-6 oz)
Doves are 3-4 times longer and around 20-30 times heavier than these tiny hummingbirds.
So while most familiar backyard birds are many times larger than the rufous-tailed hummingbird, it holds its own with its blazing fast flight and bold nature!
Unique Adaptations to Small Size
The rufous-tailed hummingbird’s diminutive size necessitates some special physiological adaptations:
– Extremely high metabolic rate – Their high energy lifestyle requires consuming over half their weight in nectar daily! This is the highest weight-specific metabolic rate of all warm-blooded animals.
– Rapid heart rate – At rest, their heart beats around 500 times per minute. In flight, it can reach as high as 1,200 beats per minute. This allows adequate oxygen circulation to power flight.
– Specialized flight muscles – Their flight muscles make up around 25-30% of their total body weight. This large muscle mass contribution provides the power needed for sustained hovering and flight.
– Minimal fat reserves – To stay lightweight, rufous-tailed hummingbirds store very little fat. This means they need to feed frequently to avoid starvation.
– Light, porous bones – Their specialized skeletons contain minimal, spongy bone material to minimize weight.
– Small clutch size – They lay very small clutches of only 2 tiny eggs. Larger clutches would be energetically demanding.
So while rufous-tailed hummingbirds are tiny, they have evolved perfect adaptations to allow them to not just survive, but thrive with their petite frames!
Conclusion
While weighing only as much as a few coins, the rufous-tailed hummingbird’s diminutive size allows incredible aerial agility and metabolism. Their specialized adaptations allow them to hover, fly, and feed energetically despite being one of the smallest warm-blooded animals. So while you need to look closely to observe a rufous-tailed hummingbird, you will be rewarded with seeing a true marvel of miniaturization in action!
