The bee hummingbird, known scientifically as Mellisuga helenae, is the smallest bird in the world. Native to the island of Cuba, this tiny bird is only about 5 to 6 centimeters long and weighs between 1.6 to 2 grams.
Quick Facts on the Bee Hummingbird
Here are some quick facts about the bee hummingbird:
- Smallest bird in the world
- Native to Cuba
- Length: 5-6 cm
- Weight: 1.6 – 2 grams
- Heart rate: >1200 beats per minute
- Wings beat 80 times per second
- Nectar-eating
As you can see from the quick facts, the bee hummingbird weighs only 1.6 to 2 grams. That’s lighter than a penny! Keep reading to learn more details about this tiny bird’s weight.
Detailed Breakdown of Weight
The average weight of an adult bee hummingbird is between 1.6 and 2 grams. However, there can be slight variations in weight based on factors like:
- Age – younger hummingbirds weigh less
- Sex – males are slightly heavier than females
- Time of day – weight is lower in the morning before feeding
- Season – birds weigh more before migration in the fall
Based on research studies, here is a more detailed breakdown of the range of weights for bee hummingbirds:
| Type | Weight Range |
|---|---|
| Males | 1.8 – 2.2 g |
| Females | 1.6 – 2.0 g |
| Juveniles | 1.5 – 1.8 g |
As you can see, adult male bee hummingbirds tend to be at the upper end of the range at 2.2 grams while juvenile females are at the lower end at 1.5 grams. But overall, their miniscule size means the birds weigh no more than a few paperclips!
Weight Relative to Size
One reason the bee hummingbird weighs so little is because of its extremely small size. Consider the following size comparisons:
- Bees are often bigger than the bee hummingbird
- Their eggs are the size of coffee beans
- They are shorter than an adult human’s thumb
Being so tiny for a bird means their overall weight is also incredibly light. The bee hummingbird is about 1/25th the size of the average hummingbird species. Since weight is correlated with size, they tip the scales at only 1.6 to 2 grams despite having rapid heart rates and high metabolisms.
Feather Weight Contributes
Another reason the bee hummingbird is so lightweight is because of the weight of its feathers. Features of the feathers include:
- Small surface area – less feather material needed
- Hollow shafts – less mass per feather
- Minimal down feathers – lack the dense downy layer of other birds
The small feathers and lack of down allow the bird’s weight to remain low. If the feathers were larger and denser, this could add more grams of weight.
Low Fat Reserves
Fat reserves also influence the bee hummingbird’s tiny weight. Some key points about their fat stores:
- Need to feed frequently due to high metabolism
- Don’t often have surplus calories to store as fat
- May starve overnight if unable to feed
- Minimal fat deposits even before migration
With such limited fat reserves, the bee hummingbird has little excess weight from fat. This is unlike some migratory birds that may nearly double their body weight before a long journey.
Weight Changes Throughout the Day
Due to their very high metabolism, bee hummingbirds need to eat frequently throughout the day. This means their weight fluctuates in a daily cycle:
- Morning – weigh least after fasting overnight
- Midday – weigh more after eating many small meals
- Evening – weigh most at end of day after maximal eating
Researchers studying wild bee hummingbirds found that individuals weighed 17-25% more in the evening compared to the morning. Their weight can change by up to 0.5 grams over the course of a day.
Measuring Methods and Tools
Given their tiny size, special methods and tools are needed to accurately measure the weight of bee hummingbirds:
- Precision scales calibrated in increments of 0.01 g or less
- Holding the bird inside a small breathable bag or box on the scale
- Subtracting the weight of the container first
- Weighing multiple times and using the average
Using high precision scales is vital. Kitchen food scales are not sensitive enough to accurately weigh animals this small. Specialized microbalances or jewelry scales are required.
Does Weight Change Seasonally?
Bee hummingbird weight can fluctuate slightly depending on the time of year. Here are some seasonal factors that may affect weight:
- Fall migration – May gain 10-15% pre-migration due to extra feeding
- Winter – Weight is most stable during non-breeding months
- Spring breeding – Males lose some weight through aerial displays
- Molting – Higher food intake needed to regrow feathers twice annually
While seasonal factors cause some variations in weight, the differences amount to just tenths of a gram given the bee hummingbird’s tiny size.
Weight and Energy
The bee hummingbird’s extremely small weight ties into its energy needs. As the smallest warm-blooded animal, some key facts about its energy requirements:
- Extremely high metabolism for their size
- Burn calories at 8-10 times the rate of an elephant
- Consume up to half their weight in nectar daily
- Constantly on the brink of starvation
- High risk of overnight starvation if unable to feed
Their disproportionately high energy needs relative to their weight reflects the costs of being the smallest endothermic vertebrate. Maintaining a high constant body temperature requires continually taking in calories.
Impacts of Low Weight
The bee hummingbird’s tiny weight has both advantages and disadvantages. Some of the impacts include:
| Advantages | Disadvantages |
|---|---|
| – Agility and maneuverability in flight | – Higher risk of starvation |
| – Easy dispersion of species to new areas | – Challenges keeping warm at night |
| – Less energy needed for takeoff and flight | – Limits on migration distance |
Their low weight contributes to the bee hummingbird’s flying skills but also poses risks due to higher energy demands.
Male vs Female Weight
On average, male bee hummingbirds weigh slightly more than females. Some differences include:
- Males average 1.8-2.2 g compared to 1.6-2.0 for females
- Males may have larger fat reserves to support courtship dives
- Females may weigh less due to egg production
- Juveniles difficult to sex as no size difference initially
The slight male skew in weight is likely tied to behaviors and demands specific to each sex. But in general, male and female bee hummingbirds are similarly diminutive.
Weight Compared to Other Hummingbirds
All hummingbirds are petite, but the bee hummingbird is the smallest. To understand its minuscule weight, it helps to compare to other hummingbird species:
| Species | Weight Range |
|---|---|
| Bee Hummingbird | 1.6 – 2 g |
| Lucifer Hummingbird | 2 – 3 g |
| Calliope Hummingbird | 2.4 – 3 g |
| Ruby-throated Hummingbird | 3 – 5 g |
| Rufous Hummingbird | 3 – 5 g |
| Blue-throated Hummingbird | 7 – 9 g |
At just 1.6 to 2 grams, the bee hummingbird is the featherweight of the hummingbird family! The other species may be double or triple the bee hummingbird’s weight.
Changes Over Lifespan
Baby bee hummingbirds gain significant weight in their first week after hatching. The weight changes over their lifespan include:
- Hatchlings weigh 0.6 – 0.9 g
- May double weight in first week
- Fledge at around 1.5 g after 2-3 weeks
- Reach full adult weight after about 3 months
- No significant decline in old age if survive over 5 years
Their rapid growth after hatching allows them to quickly take flight and feed independently. After fledging, their weight steadily increases until adulthood when they reach a stable size.
Weight and Diet
The bee hummingbird’s primary food source is nectar from flowers. Their tiny weight influences their feeding habits:
- Require relatively large amounts of nectar for their size
- Compensate with near-constant eating throughout the day
- Prefer higher concentration nectar with more calories
- Also consume insects for supplemental protein
- Help pollinate plants through feeding
Flower nectar provides the high energy density diet these miniscule birds need. And in the process, their appetite helps pollinate plant species.
Weight Loss Overnight
Without the ability to feed at night, bee hummingbirds can lose weight overnight while fasting. Nighttime weight loss can include:
- Burning up fat reserves accumulated during the day
- Depleting glycogen stores in the liver
- Breaking down muscle protein after exhausting other reserves
- Losing up to 10% of total body weight overnight
To minimize overnight weight loss, bee hummingbirds may enter torpor, a short-term hibernation that lowers their metabolic rate and energy usage. Even so, these tiny birds burn through calories astonishingly fast while fasting at night.
Weight Gain Before Migration
Some bee hummingbirds migrate short distances between Cuba and Florida. Prior to fall migration, they may gain weight by:
- Increasing feeding in last two weeks on Cuba
- Accumulating additional fat reserves
- Gaining 10-15% more weight pre-migration
- Provides energy buffer for long overwater flight
This pre-migration weight gain helps prepare for a strenuous 500-mile journey. However, even at peak weight, the bee hummingbird still weighs no more than 2.2 grams total.
Measuring Weight in the Field
Weighing wild bee hummingbirds requires specialized methods and tools. Field techniques include:
- Using hand-held microbalances capable of 0.01 g precision
- Capturing birds in mist nets for rapid weighing
- Weighing in thin breathable bags or holding boxes
- Banding birds for tracking individual changes
- Recording time of day, age, sex, season, etc.
Repeated measures of the same individuals across various conditions has provided much of the data about weight changes in bee hummingbirds across the day, season, and lifespan.
Weight and Reproduction
The energy demands of reproduction may impact bee hummingbird weights. Some relevant factors include:
- Males perform elaborate dives to impress females
- Building nests and incubating eggs burn extra calories
- Raising chicks requires feeding them every 30 minutes
- Females produce tiny eggs weighing 0.2 grams
- Breeding season weight loss possible if food is limited
Despite the high cost of breeding, most weight impacts are small due to the bee hummingbird’s naturally diminutive size. But providing for offspring does require greater energy expenditure.
Weight and Flight
The bee hummingbird’s remarkably light weight helps enable its unique flight abilities. Advantages include:
- Wings can beat up to 80 times per second
- Extreme agility in flight maneuvers
- Ability to hover in place by precisely balancing weight
- Rapid takeoff and acceleration from rest
- Enhanced dispersal ability across distances
By limiting overall body mass, the tiny bird can make the most of its muscle power to achieve unrivaled flight dexterity.
World’s New Smallest Bird
The bee hummingbird has competition for the title of world’s smallest bird. In 2021, researchers described a new hummingbird species called the rusty-breasted flowerpiercer. Found in Peru and Bolivia, initial samples suggest it may weigh 0.4 grams less than the bee hummingbird. If confirmed as a separate species, this could make it the new featherweight record holder.
Conclusion
In summary, the bee hummingbird is the smallest bird in the world and weighs only 1.6 to 2 grams on average. Their miniscule size contributes to a disproportionately fast metabolism and the need to consume up to half their body weight in nectar daily. Specialized scales and methods are required to accurately measure these tiny birds. While small, the bee hummingbird makes the most of its lightweight frame to achieve remarkably agile and swift flight.
