Ruby-throated hummingbirds are one of the most common hummingbird species found in North America. They get their name from the bright red or ruby colored throat patch on the males. Ruby-throated hummingbirds have extremely high metabolisms and must consume large amounts of nectar each day to survive. Their primary food source is flower nectar and the occasional insect or spider. In order to meet their high energy demands, ruby-throated hummingbirds have evolved specialized beaks and tongues to access nectar from flowers. Their beaks are long and slender, perfectly adapted for reaching into tubular flowers. Their tongues are bifurcated, meaning they split into two tines at the end. This allows them to lap up nectar more efficiently. Ruby-throated hummingbirds also have excellent vision and can see wavelengths of light that humans cannot, including ultraviolet light. This helps them locate nectar guides on flowers. In addition to drinking nectar, ruby-throated hummingbirds will eat small insects for essential protein. They have many interesting adaptations that allow them to thrive on their high-energy diet.
What is nectar?
Nectar is a sugary liquid produced by plants, especially in flowers. It serves as a reward or payment to pollinators in exchange for transfering pollen from one flower to another. The main components of nectar are water, sugars (sucrose, glucose, fructose), and trace amounts of amino acids, vitamins, minerals, and essential oils. The exact concentration of sugars in nectar varies by plant species. Some common nectar sugar concentrations are:
- Trumpet vine – 23%
- Cardinal flower – 32%
- Bee balm – 35%
- Salvia – 18%
- Wild bergamot – 12%
Plants actively produce and secrete nectar through glands called nectaries. Nectar production increases during flowering seasons when pollination is most crucial. For hummingbirds, nectar provides an excellent source of fast energy in the form of simple sugars.
How do ruby-throated hummingbirds access nectar?
Ruby-throated hummingbirds have specialized physical adaptations that allow them to access nectar from flowers. These include:
Needle-like bill
Ruby-throated hummingbirds have very slender, pointed beaks that function like needles. Their bills are perfectly designed for reaching deep into tubular flowers to access the nectar inside. Their bill length closely matches the flower types they feed from.
Small size
Weighing only 2-6 grams, ruby-throated hummingbirds are the smallest hummingbird species in North America. Their tiny size allows them to hover in place and exploit flowers that other larger birds cannot. Their light body weight also reduces the energy needed for flight.
Bifurcated tongue
Ruby-throated hummingbirds have tongues that split into two tines at the end. They can extend their tongues up to two times the length of their bill. When feeding, they pump their tongues rapidly in and out of flowers. The forked tips lap up more nectar with each lick.
High metabolism
Ruby-throated hummingbirds have incredibly fast metabolic rates. At rest, their hearts beat up to 250 beats per minute. In flight, their hearts can reach as high as 1,260 beats per minute. Their rapid metabolism allows them to generate enough energy to support hovering flight.
How much nectar do ruby-throated hummingbirds need?
To support their metabolically demanding lifestyle, ruby-throated hummingbirds need to consume large quantities of energy-rich nectar each day. Here are some key facts about their nectar requirements:
- Ruby-throated hummingbirds consume up to half their body weight in nectar per day. For a 3 gram hummer, that would be 1.5 grams of nectar daily.
- They feed every 10-15 minutes throughout the day and visit hundreds to thousands of flowers daily.
- Their daily energy requirement is 3000-8000 kilojoules. For comparison, an average adult human needs around 8400 kilojoules daily.
- During migration and cold overnight periods, they may enter torpor to conserve energy.
Ruby-throated hummingbirds monitor their energy reserves very closely. When their weight drops due to insufficient nectar, they become lethargic to reduce energy expenditure. Access to adequate nectar sources is critical at all times to these tiny birds.
What types of flowers do ruby-throated hummingbirds get nectar from?
Ruby-throated hummingbirds prefer flowers with tubular shapes that accommodate their long, slender beaks. They obtain nectar from both exotic and native plant species. Here are some of their favorite nectar sources:
Native plants
- Cardinal flower
- Bee balm
- Colombine
- Trumpet creeper
- Wild bergamot
- Butterfly weed
These native plants coevolved with ruby-throated hummingbirds and cater to their needs. The birds play a key role in pollinating these flowers in exchange for nectar.
Exotic plants
- Fuchsia
- Lantana
- Petunia
- Salvia
- Nasturtium
- Verbena
These exotic garden plants, many originating from Mexico and South America, also provide good nectar sources. Ruby-throated hummingbirds readily adapted to exploit these nonnative species.
Feeders
Ruby-throated hummingbirds will supplement natural nectar sources with feeders containing artificial nectar (sugar water). Feeders provide a consistent food source but lack the micronutrients of real flower nectar.
How do ruby-throated hummingbirds feed on nectar?
Ruby-throated hummingbirds have an intricate feeding process that allows them to maximize nectar uptake:
Step 1: Hover at flower entrance
Ruby-throated hummingbirds can beat their wings up to 70 times per second to generate enough lift to hover. Hovering allows them to maintain access to a flower without wasting energy on landing and takeoff.
Step 2: Insert bill into flower
They use their slender bills to reach deep inside tubular flowers and access the nectar within. Their bill length matches their preferred flower types.
Step 3: Extend tongue into nectar
With their bill inserted into the flower, ruby-throated hummingbirds extend their bifurcated tongues along grooves in the bill up to 6-12 cm to reach the nectar pool.
Step 4: Pump tongue in and out
Ruby-throated hummingbirds rapidly pump their tongues in and out around 10 times per second. The forked tips lap up more nectar with each stroke.
Step 5: Trap nectar with tongue tips
Tiny, hair-like structures along the edge of the tongue tips trap nectar through capillary action. Nectar moves up the tongue grooves by capillary action as well.
Step 6: Retract tongue to swallow
After the tongue is covered with nectar, the ruby-throated hummingbird retracts it and squeezes the nectar off the tongue to swallow it. The cycle then repeats many times.
How does the ruby-throated hummingbird’s diet change by season?
The ruby-throated hummingbird’s diet shifts across seasons as flower availability changes. Here is how their nectar and insect consumption fluctuates:
Spring
Spring is the key breeding season. Ruby-throated hummingbirds feed heavily on early blooming flower sources and eat more insects to meet protein needs for egg production.
Summer
Flowering peaks in summer, providing abundant nectar. Ruby-throated hummingbirds consume primarily nectar at this time of year and build up fat stores.
Fall
Flowering declines in fall, so ruby-throated hummingbirds increase visits to feeders before migration. They max out fat reserves in preparation for their nonstop journey.
Winter
Ruby-throated hummingbirds spend winters in Central America. They get nectar from tropical flowers and often compete with other hummingbird species on their wintering grounds.
| Season | Nectar Sources | Insect Consumption |
|---|---|---|
| Spring | Early blooms, tree sap | Higher for protein needs |
| Summer | Peak flowering | Lower |
| Fall | Late flowers, feeders | Lower |
| Winter | Tropical flowers | Lower |
How do ruby-throated hummingbirds eat insects and spiders?
In addition to nectar, ruby-throated hummingbirds get essential protein, vitamins, minerals, and fat from small insects and spiders. Here’s how they capture these prey:
- They pluck tiny insects like gnats, aphids, fruit flies, and thrips right out of the air.
- They glean crawling insects like ants and spiders off leaves, branches, and the ground.
- They occasionally capture slightly larger insects like beetles and winged termites in flight.
- They ingest primarily soft-bodied insects that are easy to digest.
- Spider silk provides a valuable source of protein.
Although insects comprise only a small percentage of their diet, they provide balance to an otherwise sugar-rich nectar diet. Young hummingbirds need more protein for growth and development.
How do seasonal changes impact ruby-throated hummingbird feeding behavior?
Ruby-throated hummingbirds alter their feeding patterns and behavior based on changing environmental conditions across seasons.
Spring
In spring, ruby-throated hummingbirds are highly territorial. Males defend nectar sources from other males and potential competitors. This ensures adequate food for breeding and raising young.
Summer
As more flowers bloom in summer, the birds spend more time feeding and less time defending territories. Their primary goal is fat storage in preparation for migration.
Fall
Food becomes more scarce in fall. Ruby-throated hummingbirds visit more feeders and may compete more aggressively at food sources. They strive to maximize energy reserves before migrating.
Winter
On their tropical wintering grounds, food competition increases. Ruby-throated hummingbirds adapt by expanding their feeding locations and times. They may tolerate other bird species more during winter.
Conclusion
Ruby-throated hummingbirds have remarkable adaptations that allow them to survive on a nectar-based diet. Their specialized beaks, tongues, vision, and flying abilities equip them to exploit tubular flowers. Ruby-throated hummingbirds consume up to half their body weight in nectar daily from hundreds of flowers. They prefer red, tubular-shaped flowers with adequate sugar concentrations. While flower nectar provides their main energy source, they also capture small insects for essential protein and nutrients. Ruby-throated hummingbirds alter their feeding behavior and patterns based on seasonal conditions and flower availability throughout their range. Their ability to meet their extreme energy needs from nectar ultimately enables their unique hovering lifestyle.
