Quick Answer
The Black-chinned Hummingbird (Archilochus alexandri) is a small hummingbird species found in western North America. An adult Black-chinned Hummingbird typically weighs between 2.6 – 4.2 grams (0.09 – 0.15 oz). The males tend to be slightly larger than the females.
Weight Range
The weight of a Black-chinned Hummingbird can vary based on several factors:
Age
Younger hummingbirds weigh less than mature adults. A new hatchling may weigh as little as 0.6 grams. As the chick develops and grows, it will gradually increase in weight.
Sex
As with many bird species, male Black-chinned Hummingbirds are typically larger than females. On average, males weigh 0.2 – 0.5 grams more than females.
Time of Year
A hummingbird’s weight may fluctuate somewhat throughout the year as it gains and loses fat reserves. In winter or during migration, a Black-chinned Hummingbird may weigh less due to burning through stored fat to fuel its high metabolism.
Geographic Location
The size and weight of Black-chinned Hummingbirds can vary slightly across their range. For example, those at the northern limits of their range may be somewhat larger to help retain body heat.
Individual Variation
There is natural variation in size between individual hummingbirds, meaning some may fall at the lower or upper ends of the typical weight range. Things like genetics, health, and resource availability while growing can influence this.
Typical Weight Range
Taking these factors into account, the average weight range for Black-chinned Hummingbirds is:
| Age/Sex | Weight Range |
|---|---|
| Hatchlings | 0.6 – 1 grams |
| Juveniles | 1.8 – 3 grams |
| Adult males | 3.2 – 4.5 grams |
| Adult females | 2.6 – 4 grams |
As the table shows, a hatchling Black-chinned Hummingbird may weigh only 0.6 grams but an adult male can reach up to 4.5 grams. The average for adult males is around 3.5-4 grams, and for adult females is 3-3.5 grams.
How Their Size Compares to Other Hummingbirds
The Black-chinned Hummingbird is a relatively small hummingbird species. Here’s how its weight range compares to some other common North American hummingbirds:
| Species | Weight Range |
|---|---|
| Ruby-throated Hummingbird | 2.4 – 4.5 grams |
| Black-chinned Hummingbird | 2.6 – 4.2 grams |
| Rufous Hummingbird | 2.7 – 5.5 grams |
| Calliope Hummingbird | 2 – 3.4 grams |
| Broad-tailed Hummingbird | 3 – 4.5 grams |
| Anna’s Hummingbird | 3 – 6 grams |
The Black-chinned Hummingbird overlaps in the small to medium size ranges with species like the Ruby-throated, Calliope, and Broad-tailed Hummingbirds. Larger hummingbirds like the Rufous and Anna’s exceed the maximum weight of the Black-chinned.
Why Their Small Size Matters
The tiny size and weight of hummingbirds like the Black-chinned plays an important role in their lifestyle and adaptations. Here are some key reasons their small size matters:
High Metabolism
Hummingbirds have extremely high metabolism to power their rapid heart rate and non-stop motion. Their small size helps minimize their energy needs for basic functions.
Agile Flight
Weighing only a few grams allows hummingbirds to hover and change direction rapidly in flight. Quick maneuvers are essential for accessing flowers and evading predators.
Thermoregulation
Tiny body size makes it challenging for hummingbirds to retain heat at night or in cool weather. Extra fat reserves provide crucial insulation.
Water Balance
With their high activity level, hummingbirds are at risk of dehydration. Their small size reduces overall water needs and makes it easier to excrete excess moisture.
Small Nest Sites
Tiny hummingbirds can utilize small crevices and branches unsuitable for larger birds when building nests. Their petite size suits their preferred nesting habitats.
How Much They Eat to Fuel Their High Metabolism
Due to having the highest metabolism of any warm-blooded animal, hummingbirds have voracious appetites relative to their size. Here are some facts about a Black-chinned Hummingbird’s food consumption:
– An adult eats over half its body weight in nectar each day. A 4 gram hummingbird would consume over 2 grams of nectar.
– They eat every 10-15 minutes when active, visiting hundreds of flowers daily.
– High energy needs mean hummingbirds can starve within hours if deprived of food. Availability of nectar sources is a key limiting factor.
– To meet nutritional needs beyond nectar, they eat tiny insects including mosquitoes, fruit flies, spiders, and aphids.
– During cold periods when flowers are less abundant, hummingbirds increase insect consumption to obtain essential protein and fat.
– Before migration, they may double their normal food intake in order to accumulate fat reserves for the journey.
– Hummingbirds have the highest mass-specific metabolic rate of any vertebrate. The Black-chinned’s is around 86 kJ per day per kg of body weight at rest.
– Their extreme metabolism requires an efficient circulatory system. At up to 1,200 beats per minute, hummingbird hearts pump at the highest known rate.
Changes in Weight at Different Life Stages
The Black-chinned Hummingbird’s energy needs and weight fluctuations can vary across its annual life cycle:
Nestlings
– Hatchlings weigh 0.6 – 1 gram, increasing to 1.8 – 3 grams over 2-3 weeks.
– Parents make hundreds of feeding trips, providing regurgitated insects and nectar.
– Rapid growth supported by high-protein diet.
Fledglings
– Leave nest at 18-25 days old, weighing 2.2 – 3.5 grams.
– Learn to feed independently over 2-3 weeks.
– Gain flight skills and forage on their own.
Juvenile to Adult
– Reach adult size at 1-2 months old.
– Adult males average 3.5-4 grams, females 3-3.5 grams.
– Establish breeding and migratory patterns.
Pre-Migration
– Increase eating in late summer to store fat.
– May increase weight by 25-40% in anticipation of migration.
– Heavier body weight provides energy reserves.
Migration
– Depart September to November depending on destination.
– Fly 500-2000 miles, using up to 0.08 grams of fat per hour.
– Arrive at overwintering grounds lighter.
Wintering
– Maintain lower weight by balancing food intake and energy expenditure.
– Require abundant food sources through the winter months.
Tracking Weight Changes in Hummingbirds
Scientists and banding programs track the weight changes of hummingbirds by:
– Periodically capturing and weighing marked individual birds.
– Comparing weights at different life stages and times of year.
– Calculating rate of fat gain leading up to migration.
– Correlating weather variables with both fat gain and loss.
– Following offspring growth rates through periodic checks at the nest.
– Documenting how fledglings gain flight skills as they lose weight.
– Noting arrival weights at overwintering grounds compared to departure.
Banding data allows the weight dynamics of hummingbirds to be studied in relation to migration, breeding, weather patterns, and environmental conditions. This contributes to understanding the energy requirements that drive feeding behaviors.
Typical Weight Tracking for a Black-chinned Hummingbird
Here is an example of key weight milestones over the first year of life for a typical Black-chinned Hummingbird:
| Age | Weight (g) | Notes |
|---|---|---|
| Hatchling | 0.8 | Tiny, eyes closed |
| 10 days | 1.5 | Pin feathers visible |
| Fledging | 2.8 | Leaves nest |
| Juvenile | 3.2 | Resembles adult |
| Pre-migration | 4.5 | Maximum fat stores |
| Post-migration | 3.0 | Burned fat in flight |
| Next Spring | 3.7 | Adult weight regained |
This demonstrates the cycle of rapid weight gain as a nestling, loss of weight while fledging, pre-migration fattening, and dip in weight after a long migration south. Tracking weights at different phases helps illuminate the biology of these tiny birds.
Unusual Weight Conditions
While in their normal weight range, hummingbirds are as healthy and energetic as their genetics and environment allow. However, there are some abnormal weight situations that could negatively impact health:
Overweight
– Extremely rare in the wild.
– Could impair flight agility essential for foraging.
– May indicate issues with fat metabolism.
Underweight
– Common if food availability or competition decreases.
– Insufficient energy reserves and higher risk of starvation.
– Can be caused by harsh weather, habitat loss, injury, or illness.
– Reduced muscle mass and weaker flight capability.
Obese
– Occurs in captive birds on high-sugar diets.
– Leads to liver damage and heart failure if unchecked.
– Usually unable to fly which further compounds problems.
Emaciated
– Advanced state of starvation.
– Minimal fat or muscle tissue remaining.
– Often the result of prolonged environmental stress.
– High chance of mortality without rapid intervention.
Conclusion
In summary, the typical weight range for a Black-chinned Hummingbird is 2.6 – 4.2 grams. Their extremely small size compared to other birds is a key adaptation linked to their high metabolism, agile flight, and reliance on plentiful nectar and insects. Tracking weight changes across the annual cycle provides insights into hummingbird biology and energy budgets. Maintaining an optimal weight range and fat reserves is crucial to their survival in the wild. Careful weight monitoring and management is also important for any hummingbirds kept in captivity. Their tiny size means even small deviations from normal can have a severe effect. In the wild, Black-chinned Hummingbirds must maintain a delicate energy balance to endure their strenuous lifestyle.
