Where do hummingbirds get their energy from?

Hummingbirds are remarkable little birds that have captivated people for centuries with their beauty and amazing flying abilities. Despite their tiny size, hummingbirds have incredibly high metabolisms and must consume a tremendous amount of energy to support their rapid wing beats and hovering flight. So where exactly do hummingbirds get all their energy from?

Nectar

The primary food source for hummingbirds is nectar from flowers. Hummingbirds have specially adapted long, slender beaks and tongues that allow them to reach inside flowers and extract the sugary nectar. Nectar provides hummingbirds with rapid energy in the form of sugars that can quickly be metabolized for energy. Hummingbirds have the highest metabolism of all animals relative to their size – a resting hummingbird takes about 250 breaths per minute, and their hearts can beat up to 1,200 times per minute during flight. To meet their extreme metabolic demands, hummingbirds go into a sort of sugar coma each night, lowering their body temperature and heart rate so they can conserve energy until morning.

When feeding on nectar, hummingbirds prefer flowers with a higher sugar concentration, as these provide more efficient energy. Some native plants favored by hummingbirds include:

• Trumpet vine
• Coral honeysuckle
• Columbine
• Bee balm
• Butterfly weed
• Salvia

Hummingbirds have good color vision and are attracted to tubular reddish or orange flowers, which advertise that they contain lots of sugar. Hummingbirds also “trap-line,” repeatedly visiting favorite nectar sources in efficient routes to maximize their sugar intake.

Insects and Spiders

While nectar provides the majority of a hummingbird’s diet, they also get essential protein, vitamins, minerals, and fats from consuming small insects and spiders. After a nectar feeding, hummingbirds often perch briefly to hawk flying insects out of the air. They also glean insects from leaves and bark. Preferred insect prey includes:

• Mosquitoes
• Fruit flies
• Gnats
• Aphids
• Spiders
• Caterpillars

Young hummingbirds rely more heavily on insects to get the protein required for growth and development. While adult hummingbirds meet about 80% of their energy needs from sugary nectar, insects and spiders may provide up to 25% of the diet for juveniles.

Sap

In early spring when flowers are still scarce, hummingbirds will drink tree sap for an energy source. Saps offer a concentrated source of sugars, though not as rich in calories as flower nectar. Hummingbirds use their specialized beaks to pierce holes in tree bark to extract sap. Favorite sap sources include:

• Maple trees
• Birch trees
• Willow trees

Drinking sap likely provides some minerals and nutrients in addition to sugar calories. This helps tide hummingbirds over until more spring blooms open up.

The Importance of Feeders

In many habitats, especially urban or residential areas, flowering plants may not adequately supply the nectar demands of hummingbird populations. This is where backyard hummingbird feeders can play a crucial role in providing supplemental food. Feeders allow people to observe and enjoy hummingbird behaviors and help ensure the birds can access enough calories to thrive.

Here are some tips for optimal hummingbird feeders:

• Use a clean narrow-tube feeder designed especially for hummingbirds
• Fill with a 4:1 ratio of white refined sugar to water
• Avoid red food dye, honey, or artificial sweeteners
• Change the sugar water every 2-3 days, or daily in hot weather
• Clean feeders thoroughly every 1-2 weeks
• Place feeders in a shady location

With a properly maintained feeding station, backyard enthusiasts can provide an excellent supplemental nectar source for local hummingbird populations.

How Many Calories Do Hummingbirds Need?

The calorie requirements of hummingbirds are astounding for their tiny size. An average hummingbird has a mass of only 3-6 grams. But to hover and fly, they require the same amount of energy per gram of tissue as a marathon runner!

Here are some facts about hummingbird energy needs:

• During the day, hummingbirds consume up to half their body weight in nectar sugars
• Their daily calorie requirement is around 400-500 calories
• This is 25-100 times more calories per unit of body mass compared to an elephant or ostrich
• To store energy, hummingbird livers can hold up to 16% of their total body weight in glycogen
• Overnight, their metabolic rate drops to 1/15th of their active daytime rate to conserve energy

Given their extreme energy usage, it’s no wonder hummingbirds are continually seeking out nectar sources and feeding up to every 10-15 minutes throughout the day. They can starve in as little as 2 hours if unable to adequately replenish their depleted fuel stores.

This table helps put into perspective just how incredibly energetically demanding hummingbird flight is!

Unique Adaptations for High Energy Lifestyles

Hummingbirds have many unique anatomical and physiological adaptations that enable their sugar-powered hovering flight:

• Wings – Their wings connect to their shoulders in a way that allows them to rotate in a full circle. They flap at high frequencies of 50-70 times per second.
• Feather structure – Their feathers are very lightweight and stiff to reduce drag.
• Heart – Their heart rate can reach 1,260 beats per minute and their heart accounts for 2.5% of their total body weight.
• Lungs & air sacs – Their enlarged lung capacity and air sacs deliver more oxygen.
• Weight – They maintain an extremely low fat percentage to reduce body mass.
• Low temperature – They have the lowest body temperature of all birds at 96-106°F to conserve energy.

All these specializations allow hummingbirds to meet their sky-high metabolic demands and subsist almost entirely on sugar calories from flower nectar.

How Do Hummingbirds Get Fat?

Even though they are constantly burning through calories, hummingbirds are still capable of building up fat stores to help provide energy and insulation during times of scarcity or high energy expenditure. Here’s how hummingbirds are able to accumulate fat:

• Overeating – Hummingbirds intentionally overeat, consuming more calories than they burn, resulting in fat deposition and weight gain over time.
• Lower activity – Fat storage happens more during rest or in cooler weather when less energy is required for heat generation or flight.
• Dietary fats – Some dietary fats from insect meals help contribute to fat stores. Fats pack over twice the calories per gram compared to carbohydrates.
• Liver glycogen – Excess sugar is converted to glycogen and stored in the enlarged liver until needed.

By opportunistically overeating and reducing energy expenditures, hummingbirds can accumulate fat deposits to help sustain them through seasonal shifts in food availability such as migration.

How Hummingbird Metabolism Changes With Migration

Hummingbird energy needs fluctuate depending on their life cycle stage and behaviors like migration. Here’s how hummingbird metabolism and energy demands shift during migration:

• Their body mass increases by 25–45% in preparation for migration, requiring more energy for flight.
• They consume more sugars and accumulate more fat to fuel migration.
• During sustained hovering flight, their metabolic rate is estimated to increase by 30–50%.
• When flying over open water during migration, their metabolism may increase by up to 100% over resting.
• This extreme energy use requires frequent stops to refuel on nectar flowers along their route.

The metabolic demands of migration create an increased reliance on flower nectar to provide enough energy to sustain hummingbirds over their long journeys between season ranges.

Do Hummingbirds Need More Calories in Cold Weather?

Hummingbirds do require significantly more calories to maintain their high metabolism in cold weather. Here’s how their energy needs increase in colder temperatures:

• Up to 80% of their calories are used to maintain body heat in cold climates.
• Lower temperatures raise their metabolic rate and calorie burning.
• In very cold weather, their metabolic rate may increase by 50-100%.
• To survive cold nights, they need adequate fat reserves or nighttime supplemental feeding.
• Exposure to long cold snaps without adequate fuel can be fatal.

Hummingbirds are prone to starvation and hypothermia when cold weather persists, as their tiny bodies lack the energy reserves to withstand sustained metabolic demands. Providing artificial feeders with high sugar nectar helps counter their increased calorie requirements in cold weather.

How Do Hummingbirds Get Water?

In addition to calories from sugars, hummingbirds also have daily requirements for water intake. Here’s how they obtain adequate hydration:

• Drinking water droplets from leaves, branches, and other surfaces
• Consuming water-rich foods like berries, tree sap, and soft insects
• Extracting water from nectar – 25% of nectar is water
• Osmosis – absorbing water vapor when airborne
• Preformed water – produced through fat metabolism

Interestingly, hummingbirds can draw in environmental water vapor and moisture right through their skin and breathing passages when in flight. This helps supplement their various water sources to prevent dangerous dehydration.

Impact of Artificial Sweeteners on Hummingbirds

Many people use artificial sweeteners in hummingbird nectar under the assumption that it is an acceptable substitute for sugar. However, artificial sweeteners like sucralose provide no energetic value or calories to hummingbirds. Relying on artificially sweetened nectar can have harmful effects:

• It does not provide usable energy to power their metabolism
• May contribute to weight loss and starvation
• Could alter taste preferences and breeding behaviors
• Long-term impacts on health are unknown

For both adult and baby hummingbirds, artificial sweeteners should be avoided. Only pure white cane or beet sugar provides the calories they require for their extreme lifestyles.

How Do Baby Hummingbirds Get Energy Before Leaving the Nest?

In their first 7-28 days of life, baby hummingbirds rely entirely on their mother’s crop milk to get the hydration and nutrition they need. The crop milk is produced in the mother’s throat and contains proteins, fats, carbohydrates, minerals, and sugars. Here’s how crop milk sustains baby hummingbird development:

• It provides 65% of their calorie needs for growth.
• The high sugar content offers quick energy.
• It has 3x the calories and more protein than adult hummingbird nectar.
• The mother may produce up to her entire body weight in crop milk per day.

This nutrient-dense crop milk allows hummingbird chicks to achieve their incredible 300-700% weight gain before fledging the nest. Once independent, the juveniles switch to drinking nectar for their main energy needs.

Conclusion

Hummingbirds have one of the highest metabolic rates of any animal, requiring tremendous amounts of energy to power their unique hover-and-fly lifestyle. They primarily get their calories from drinking sugary flower nectar, along with some essential proteins and nutrients from insects/spiders. Key physiological adaptations like rapid breathing and heart rate allow them to quickly convert sugars into usable energy. While hummingbird metabolisms fluctuate with behaviors like migration and with environmental conditions like cold, adequate flower or feeder nectar keeps their tiny bodies fueled up. Understanding the extreme nutritional demands of hummingbirds can help hummingbird enthusiasts better support these special birds.