The ruby-throated hummingbird (Archilochus colubris) is a fascinating little bird known for its iridescent feathers and ability to hover in midair as it feeds on nectar from flowers. These tiny birds are the only breeding hummingbird species found east of the Mississippi River and are a familiar sight in summer gardens across Eastern North America. Their diet is unique among birds and allows them to fuel their high-energy lifestyle. So what does the ruby-throated hummingbird eat?
Nectar
Nectar is the ruby-throated hummingbird’s main food source. These birds have specially adapted long, slender beaks and tongues that allow them to reach into tubular flowers and lap up the sweet nectar inside. Their tongue even has a forked tip covered in tiny hair-like structures called lamellae that help draw nectar into the mouth.
Hummingbirds prefer flowers with high sugar concentrations in the nectar, typically opting for tubular or trumpet-shaped blossoms in shades of red, orange, or pink. Some of their favorite nectar-producing flowers include:
- Trumpet vine
- Bee balm
- Cardinal flower
- Petunias
- Fuchsias
- Morning glory
- Columbine
- Honeysuckle
- Lantana
To meet their high metabolism and energy demands, ruby-throated hummingbirds may visit hundreds of flowers each day. They consume approximately half their body weight in nectar daily! The average adult male weighs around 3 grams, so that equals about 1.5 grams of nectar per day. Given that typical flower nectar is between 15-25% sugar concentration, the birds ingest an estimated 0.3-0.4 calories of nectar sugar with each lick.
Insects and Spiders
While nectar makes up the majority of a ruby-throated hummingbird’s diet, they also consume small insects and spiders to obtain key nutrients not present in nectar. Insects provide protein, as well as vital micronutrients such as calcium, magnesium, sodium, and some fatty acids.
Here are some of the bugs and spiders ruby-throats are known to eat:
- Mosquitos
- Fruit flies
- Gnats
- Aphids
- Thrips
- Small bees
- Ants
- Spider eggs
- Tiny larvae
Ruby-throated hummingbirds use two main strategies for catching insects. They may hawk flying bugs out of the air, performing acrobatic twists and dives. Alternatively, they glean stationary insects or larvae off of leaves, branches, and flower buds while hovering. This versatility allows them to exploit a wide range of small invertebrates to balance their diet. Researchers estimate flying insects may comprise 5-30% of their total food intake.
Tree Sap
In early spring when few flowers are in bloom, ruby-throated hummingbirds will sip tree sap for an energy boost. They favor sap from wells drilled by yellow-bellied sapsuckers, a type of woodpecker. Accessing free-flowing sap provides hummingbirds with sugars to fuel migration and breeding. The birds also eat sap from holes in tree bark, licking it with their tongue. Favored sap sources include:
- Birch trees
- Maples
- Willows
- Hornbeams
Tree sap makes up a relatively minor portion of ruby-throated hummingbird diet the rest of the year. But in late winter and early spring, this food source becomes especially vital to migrating hummers arriving before blooms open.
How Much Food Do Hummingbirds Eat?
Ruby-throated hummingbirds need a lot of energy to support their extreme metabolisms and active lifestyles. Here’s a look at their nutritional requirements:
- Up to 12 meals per day
- Eat every 10-15 minutes while awake
- Consume pollen equal to body mass every day
- Double body weight daily in nectar
- Require 4-8 calories daily minimum
Given their tiny size, ruby-throated hummingbirds have astonishingly high energy needs. Their intake is the avian equivalent of a 150-pound person eating over 155,000 calories per day! Luckily, the birds can enter a torpor-like state at night to conserve energy when food is unavailable.
Food Source | Portion of Diet |
---|---|
Nectar | 60-100% |
Insects/spiders | 0-40% |
Tree sap | 0-5% |
This table summarizes the typical dietary composition for ruby-throated hummingbirds when all food sources are available. As you can see, nectar comprises over half their intake, with insects and tree sap making up smaller proportions. The exact ratios vary throughout the year depending on seasonal availability.
How Do Hummingbirds Eat Nectar?
Ruby-throated hummingbirds have several key anatomical and behavioral adaptations for accessing nectar:
- Long, slender beak – Ideal for probing into tubular flowers
- Forked tongue – The split tips pick up more nectar
- Extendible tongues – Can protrude past the beak to reach nectar
- Lamellae on tongue – Fringes trap nectar via capillary action
- Hovering ability – Allows precise positioning while feeding
- High lick rate – Laps nectar up to 13 times per second!
Here’s a step-by-step overview of how ruby-throats drink nectar:
1. Hover in front of flower
2. Insert beak into corolla opening
3. Extend forked tongue into nectar
4. Retract tongue, drawing nectar into mouth
5. Trap nectar in throat grooves
6. Press tongue to roof of mouth to squeeze nectar toward throat
7. Swallow and repeat!
This remarkably efficient process lets hummingbirds exploit a niche food source most other birds cannot. They can dip their slender beaks into flower after flower to harness the concentrated energy in nectar.
How Do Hummingbirds Catch Insects?
Ruby-throated hummingbirds use two tactics to snag insect prey while flying:
Hawking:
- Chase after flying insects in dramatic aerial pursuits
- Maneuver acrobatically, changing speeds and directions
- Open mouth wide to catch bugs mid-air
- Preferred technique for chasing winged insects like mosquitos, flies, aphids, and bees
Gleaning:
- Hover in front of leaves, branches, buds
- Pick off crawling bugs like ants, larvae, spiders
- Use excellent vision to spot tiny prey
- Insert narrow beak precisely to impale motionless prey
These methods allow hummingbirds to catch a variety of insects without landing. Hawking works best for snatching mobile flying insects, while gleaning lets hummingbirds exploit sedentary or hidden arthropods other birds can’t access. Together, the techniques provide essential protein-rich prey.
How Do Hummingbirds Eat Tree Sap?
Here’s how ruby-throated hummingbirds drink tree sap:
- Find sap wells drilled by sapsuckers or broken bark oozing sap
- Hover wings forward to steady themselves in front of sap source
- Poke beak directly into sap flow to lap it up
- Use long, specialized tongue to collect and transport sap
- Swallow sap, which provides quick energy from sugars
- Move to next sap source; may visit many wells/trees in a day
This sap-licking behavior relies on the ruby-throat’s adept hovering ability and perfectly suited tongue. The bird’s slender bill allows it to slurp sap directly from tiny holes drilled by woodpeckers. Tree sap provides an abundant energy boost when flowers are not yet in bloom.
How Do Hummingbirds Digest Nectar?
Ruby-throated hummingbirds have physiological adaptations that allow them to derive energy from sugary floral nectar, which is indigestible to many other birds. Here’s how they digest nectar:
- Low amylase levels – Little starch digestion needed for nectar-based diet
- Rapid food transit – Nectar passes quickly through digestive tract
- Low glucose absorption – Most absorption occurs via fructose in small intestine
- Tolerate high blood sugar – Levels 2-4 times higher than mammals
- Uric acid excretion – Nitrogen waste product requires less water
- Rapid nutrient processing – Extract energy from nectar as quickly as possible
Notable features include an extremely rapid digestive system to move nectar through swiftly, low glucose absorption that reduces strain on the pancreas, and uric acid excretion to conserve water. These traits let hummingbirds thrive on a high sugar diet that could be dangerous for other animals.
Role of Diet in Hummingbird Ecology
The ruby-throated hummingbird’s specialized diet plays an essential role in their ecosystem functions, including:
- Pollination – As nectar-feeders, hummers transfer pollen between blooms
- Seed dispersal – Small seeds get caught on beaks and feet and carried to new areas
- Insect population control – Preying on bugs helps balance invertebrate numbers
- Nectar robbery – Robbing nectar may reduce plant reproduction rates
- Indicator species – Sensitive to environmental changes, so declining numbers may signal issues
Research suggests ruby-throated hummingbirds are important pollinators. Their diet relies on nectar, so they play a vital role in transferring pollen as they move between flowers. They also help control insect populations and may aid in seed dispersal. However, nectar robbery may negatively impact some plant species. Overall, their dietary needs are closely intertwined with surrounding plant and animal communities.
What Happens if Hummingbirds Don’t Get Enough Food?
Ruby-throated hummingbirds have astonishingly high metabolic demands. Here’s what happens if they do not get enough food:
- Enter torpor to conserve energy
- Lower body temperature up to 63 degrees Fahrenheit
- Reduce breathing and heart rate
- Hibernate-like state lasts a few hours overnight
- If food shortage persists, may be too weak to fly
- Migration and breeding could be disrupted
- May starve to death within a few hours in extreme cases
To survive periods of food scarcity, ruby-throats rely on an adaptive behavior called torpor. This minimizes their energy needs when nectar or insects are unavailable, especially at night. However, torpor only provides a temporary solution. Hummingbirds may die astonishingly quickly if deprived of food for too long.
FAQs
Do hummingbirds drink water?
No, ruby-throated hummingbirds get all the water they need from nectar. There is no need for them to drink plain water. The nectar contains sufficient moisture to meet their hydration needs.
Do hummingbirds eat seeds?
Hummingbirds do not eat seeds as a significant portion of their diet. They lack the adaptations needed to process and digest most seeds. However, they may incidentally ingest small seeds while drinking nectar.
Why do hummingbirds have long beaks?
Ruby-throated hummingbirds evolved elongated, slender beaks specially adapted for reaching into tubular flowers and accessing the nectar within. Their long beaks match the shape of many nectar-producing flowers they feed from.
How fast does a hummingbird’s heart beat?
At rest, a hummingbird’s heart may beat up to 250 times per minute. In flight, that rate can double up to a staggering 500 beats per minute! This rapid heartbeat is necessary to meet their incredible metabolic demands.
Conclusion
In summary, ruby-throated hummingbirds have a specialized nectar-based diet supplemented with insects and tree sap. They possess numerous anatomical and behavioral adaptations enabling them to efficiently exploit sugary nectar and tiny invertebrate prey. Their unique dietary requirements are closely linked to their roles as pollinators, insect controllers, and indicator species. Ruby-throated hummingbird survival hinges on ample access to calorie-rich floral nectar and protein-packed bugs to fuel their extreme lifestyles. Their dietary specialization allows them to occupy an important ecological niche utilized by no other North American bird species.