Hummingbirds are some of the smallest and most energetic birds in the world. Their high metabolism requires them to consume up to twice their body weight in nectar each day just to survive! But exactly how many calories does a hummingbird eat per day? Let’s take a closer look.
How much does a hummingbird weigh?
Hummingbirds come in many different species, but on average they weigh between 2-6 grams. The smallest hummingbird species is the Bee Hummingbird which weighs only around 2 grams. The largest species is the Giant Hummingbird which can weigh up to 20 grams. Most of the common backyard hummingbird species like Ruby-throated Hummingbirds weigh 3-4 grams.
So for the purposes of this article, let’s assume we are talking about a medium sized hummingbird species that weighs approximately 4 grams.
How many calories does a hummingbird need per day?
Hummingbirds have extremely high metabolisms to power their constant hovering and darting movement. Their hearts beat up to 1,260 times per minute and they take 250 breaths per minute even at rest. This high energy lifestyle requires a lot of fuel.
On average, hummingbirds need to consume between 3-7 calories per day for every gram of body weight just to meet their basic metabolic needs. This means a 4 gram hummingbird would need:
4 grams x 5 calories/gram average = 20 calories per day
However, hummingbirds also use a tremendous amount of additional energy for flying, migrating, defending territory, courting mates, building nests, and raising young. Studies show hummingbirds double or even triple their basic metabolic rate when engaging in these high energy activities.
So the total daily calorie requirement for an active 4 gram hummingbird is likely 40-60 calories per day.
How do hummingbirds get all these calories?
Hummingbirds meet their huge daily calorie requirements by consuming floral nectar and small insects:
Calories from Nectar
– Nectar from flowers provides the main source of energy for hummingbirds.
– The sucrose concentration in flower nectar averages about 20-25%, providing approximately 0.8 calories per gram of nectar.
– Hummingbirds consume roughly 1.5-2 times their body weight in nectar each day.
– So a 4g hummingbird would drink 6-8g of nectar, providing approximately 5-6.5 calories.
Calories from Insects
– Hummingbirds also eat small insects for essential proteins and nutrients.
– Insects provide approximately 5 calories per gram.
– Hummingbirds eat 5-10% of their total food intake as insects.
– So a 4g hummingbird would eat 0.2 – 0.4g of insects, providing 1-2 calories.
Let’s add this up:
| Food Source | Calories |
| Nectar | 5-6.5 calories |
| Insects | 1-2 calories |
| Total | 6.5-8.5 calories |
This amounts to a total intake of approximately 6.5-8.5 calories per day from nectar and insects for a 4 gram hummingbird.
Do hummingbirds eat enough to meet their energy needs?
Based on the estimated calorie requirements calculated earlier, a 4 gram hummingbird needs 40-60 calories per day.
But our feeding calculations only show an intake of 6.5-8.5 calories from nectar and insects.
This means hummingbirds often do not take in enough calories from food sources alone. They make up the deficit by lowering their body temperature and entering a hibernation-like state called torpor.
Torpor reduces energy needs
– Torpor lowers a hummingbird’s metabolic rate allowing it to survive on fewer calories.
– Their body temperature drops from 105°F to as low as 60°F.
– Heart and breathing rates slow dramatically.
– Torpor reduces their energy needs by 50-70%.
– Hummingbirds enter torpor most nights and can last up to 2 weeks in torpor if food is scarce.
So by combining torpor with calories from food, hummingbirds are able to meet their huge energy demands!
In summary:
– An average 4 gram hummingbird needs 40-60 calories per day.
– They acquire only 6.5-8.5 calories from nectar and insects.
– To survive, they use torpor to reduce their energy needs by up to 70%.
– This allows them to operate on much less than their typical requirement.
So a hummingbird’s total calorie intake is quite low – but with an extremely slowed metabolic rate in torpor, those calories go a long way! This helps explain how these tiny birds can survive and thrive on such a small amount of food.
Other Interesting Hummingbird Facts:
How fast do hummingbird wings beat?
– Hummingbird wings beat up to 80 times per second – the fastest of any bird! This allows them to hover and fly backwards.
How fast does a hummingbird’s heart beat?
– A hummingbird’s heart can beat up to 1,260 times per minute while active. At rest, their heart still beats around 250 bpm.
How many calories does a hummingbird burn per hour?
– Hummingbirds burn through energy at an astonishing rate. They can burn up to 300 calories per hour while exhibiting their aerial acrobatics. That’s 30-50 times their body weight!
How far does a hummingbird migrate?
– Some hummingbird species like the Rufous Hummingbird migrate incredible distances. They fly over 3,900 miles from Alaska to Mexico twice yearly during migration.
How long does a hummingbird live?
– In the wild, hummingbirds generally live 3-5 years. The oldest known wild hummingbird was 12 years old. In captivity they may live 10-15 years.
Hummingbirds are amazing creatures, and their enormous appetite and energy needs help fuel their tiny bodies for their fast-paced lifestyles. While their total daily calorie intake appears quite small, they have finely tuned mechanisms to get by on just enough to survive and thrive.
