Hummingbirds are remarkable little creatures. Though they are tiny, often weighing less than a nickel, they have extremely high metabolisms that require them to consume up to their entire body weight in nectar each day just to survive! Their appetites are voracious but their dietary needs are quite specific.
What do hummingbirds eat?
Hummingbirds subsist almost entirely on nectar from flowers. This sweet liquid provides them with the high-energy sugars they need to power their wings for flight. Hummingbirds have evolved long slender beaks perfectly adapted for accessing nectar from blooms. As they feed, some pollen sticks to their heads and beaks, allowing them to inadvertently pollinate the flowers as they move from bloom to bloom.
While nectar is their main food source, hummingbirds also consume small insects for essential proteins and nutrients not found in nectar. They snatch bugs out of the air or glean them from foliage. Preferred tiny insects include fruit flies, mosquitoes, gnats, aphids, spider mites, and small bees.
How many calories do hummingbirds need?
The metabolism of hummingbirds is remarkably fast. Their hearts can beat up to 1,260 times per minute and they take around 250 breaths per minute, even at rest. This rapid metabolism requires a tremendous amount of energy to sustain.
To power their busy bodies, hummingbirds need to take in a huge number of calories relative to their tiny size. It is estimated that at rest, hummingbirds burn energy at a rate 10 times faster than an elephant does per gram of body weight.
Research indicates that hummingbirds require between 2,000 to 9,000 calories per day to survive. This number varies by species, with larger hummingbirds naturally requiring more calories on average than smaller ones.
How much nectar equals needed calories?
Given their high caloric requirements, how much nectar must a hummingbird drink each day to meet its energy needs? Let’s consider the ruby-throated hummingbird, one of the most common hummingbird species found in North America.
The ruby-throated hummingbird has an average body mass of 3 grams. To fuel its busy lifestyle, it needs around 3,500 calories per day. Assuming nectar is, on average, a 20% sugar solution, that means each gram of nectar contains about 0.8 calories.
Therefore, a ruby-throated hummingbird would need to consume approximately 4,375 grams of nectar each day to get 3,500 calories. That comes out to around 1.5 fluid ounces, or about half a shot glass worth of nectar daily.
| Hummingbird Species | Average Body Mass (g) | Calorie Requirement | Nectar Needed (g) |
|---|---|---|---|
| Ruby-throated | 3 | 3,500 | 4,375 |
| Rufous | 3.2 | 3,700 | 4,625 |
| Allen’s | 3.1 | 3,500 | 4,375 |
As shown in the table, nectar needs scale with body size. A larger Rufous hummingbird requires more nectar than a smaller Allen’s hummingbird, for example.
How many flower visits to meet needs?
Hummingbirds consume nectar throughout the day by visiting flower after flower. But how many blooms must a hummingbird drain on a daily basis to meet its high-energy needs?
Let’s continue with the ruby-throated hummingbird example. If a flower contains approximately 0.05 mL (0.05 grams) of nectar, our ruby-throat would need to visit around 87,500 flowers per day to get its required 4,375 grams of nectar!
That’s a lot of flowers! This helps explain why hummingbirds are constantly on the move, flitting from bloom to bloom at a dizzying pace.
Nectar Consumption by Species
| Species | Nectar Needed (g) | Flowers Visited Daily |
|---|---|---|
| Ruby-throated | 4,375 | 87,500 |
| Rufous | 4,625 | 92,500 |
| Allen’s | 4,375 | 87,500 |
The table demonstrates how nectar requirements influence the number of flowers a hummingbird must visit daily. With such voracious appetites, it’s no wonder hummingbirds zoom from bloom to bloom at a dizzying pace!
How feeding changes by season
While hummingbirds have tremendous appetites all year round, their food consumption and behavior changes slightly depending on the season.
In spring and summer, millions of flowers are in bloom, providing hummingbirds with a readily available food source. The long days of the season give them ample daylight hours to forage for nectar and insects.
In fall, as blossoms begin to fade, hummingbirds increase their intake to store up extra fat for migration. During migration itself, ruby-throats embark on a 500-mile nonstop flight across the Gulf of Mexico. This requires huge energy reserves and hyperphagia (excessive eating) beforehand.
Throughout winter in their Central American habitats, flowering is reduced. Despite the relative scarcity, hummingbirds maintain their high metabolism and consumption year-round.
How hummingbirds eat so much
The question remains: how in the world can such tiny creatures consume their entire body weight daily and visit tens of thousands of flowers to meet their needs?
Hummingbirds have many fascinating anatomical and behavioral adaptations that allow them to ingest truly incredible amounts of nectar:
- A slender, specialized beak perfect for nectar extraction
- A tongue adapted for rapid, repeated licking of nectar
- The ability to lick 10-15 times per second while feeding
- A digestive system geared for rapid processing with fast emptying time
- The ability to enter a nourishment extraction state at night, maximizing calories extracted from food while asleep
- Highly efficient kidneys that excrete minimal amounts of electrolytes allowing them to ingest more nectar
- A rapid heart rate that accelerates to fuel bursts of speed and activity
- Constant foraging from dawn until dusk, with visits to hundreds of flowers per hour
Additionally, hummingbirds have the remarkable ability to enter torpor, a short-term hibernation state, to conserve energy overnight when food intake is lower. Their body temperature and metabolic rate drops, allowing them to excerpt less energy at rest.
Key Takeaways
To summarize key points on hummingbird consumption:
- Hummingbirds have very fast metabolisms and burn calories rapidly
- They require between 2,000 – 9,000 calories per day depending on species
- Most of their calories come from nectar, requiring 1-2 fluid ounces per day
- To meet needs, they visit thousands of flowers daily, licking nectar rapidly
- Flower foraging behavior and intake increases in fall to build fat reserves for migration
- Specialized adaptations allow them to extract maximum nutrition from nectar
Conclusion
Hummingbirds may be tiny, but they have astounding appetites. Their extreme energy demands require them to consume up to 100% of their body weight in nectar each day. This involves visiting up to tens of thousands flowers daily and licking nectar at lightning speeds. Hummingbirds’ specialized physiology and behaviors allow them to meet these needs, providing the calories they need to maintain their dizzying speed and lifestyle.
