Hummingbirds and flowers have a very close and mutually beneficial relationship. Hummingbirds rely on flowers for food in the form of nectar, and in return, they serve as pollinators for many species of plants. This unique partnership has evolved over millennia, with each depending on the other for survival.
Why do hummingbirds visit flowers?
Hummingbirds have very high metabolisms and must consume large amounts of energy in the form of sugars to sustain their rapid flight and energetic lifestyle. They obtain these sugars in the form of nectar from flowers. Nectar is an energy-rich liquid produced by plants to attract pollinators. It contains glucose, fructose, and sucrose sugars that provide a high-calorie food source for hummingbirds.
Hummingbirds have specialized adaptations that allow them to obtain nectar. Their long, slender bills and tongues are perfect for reaching into tubular flowers. Their wings can beat up to 70 times per second, allowing them to efficiently hover in place while feeding. They have excellent color vision to help them locate flowers. All of these unique traits enable hummingbirds to access nectar that many other creatures cannot.
How do hummingbirds feed from flowers?
Hummingbirds use their slender, tubular tongues to reach into flowers and lap up nectar. Their tongues have forked tips that effectively collect and retrieve liquid. When feeding, they will lick or probe into a flower 10-15 times per second. The nectar adheres to the tongue through capillary action, moving up grooves along its length via surface tension. This allows hummingbirds to efficiently feed on small volumes of nectar from multiple flowers in quick succession.
In addition to nectar, hummingbirds will sometimes feed on small insects and spiders also found in flowers. The protein from these prey items complements the carbohydrate-rich nectar in their diet. To capture insects, hummingbirds will momentarily halt their energetic hovering flight to pluck bugs from foliage or flowers.
What types of flowers do hummingbirds feed from?
Hummingbirds have evolved to feed from specialized tubular flowers that match their feeding abilities. Some common flower types that attract hummingbirds include:
- Trumpet vines – These vibrant orange or red flowers have long, tapered tubes perfect for hummingbird bills. Trumpet creeper, trumpet honeysuckle, and crossvine are examples.
- Salvias – This diverse plant genus includes many species with tubular flowers in colors like red, purple, pink, and white. Pineapple sage and scarlet sage are hummingbird favorites.
- Columbines – These nodding flowers have elegant, curved spurs containing abundant nectar. Wild columbine and other Aquilegia species are pollinated by hummingbirds.
- Coral bells – Heuchera species produce hundreds of bell-shaped blooms on tall flower stalks that attract hummingbirds.
- Penstemons – Also called beardtongues, these tubular flowers come in shades like red, pink, purple, and white.
In addition to these specialized flowers, hummingbirds will visit more open-shaped blossoms like fuchsias, lilies, hibiscus, and orchids. They favor flowers that are reddish or orange in color and are typically ignored by bees or other pollinators. Planting a diversity of hummingbird-friendly flowers will help attract these energetic pollinators to a garden.
How do hummingbirds assist with plant pollination?
As they feed on nectar, hummingbirds serve as important pollinators for many flowering plants. Their wings beat so rapidly that they can hover in place, allowing them to efficiently access tubular or pendant flowers that other pollinators cannot. As they probe into each blossom with their head and bill, pollen grains stick to their feathers, head, and bill. This pollen is then transferred to the next flower they visit, resulting in cross-pollination.
Certain flower traits have evolved to specifically assist pollination by hummingbirds. Tubular flower shapes perfectly match the long bills of hummingbirds. Bright red or orange colors and lack of scent attract hummingbirds but not bees or other flying insects. Nectar with higher sugar concentrations provides the high-energy food hummingbirds need. All of these specializations facilitate hummingbird pollination.
Research has shown that hummingbird-pollinated plants produce more seeds, fruit, and offspring than self-pollinated or wind-pollinated plants. This demonstrates the vital role hummingbirds play in the reproductive success and survival of many plant species.
What is an example of a specialized hummingbird-pollinated flower?
One excellent example of a highly specialized hummingbird-pollinated flower is the firecracker bush, also known as cigar plant (Cuphea ignea). This tropical American plant produces rows of tubular orange and red flowers along its stem. The blooms have an opening just large enough for a hummingbird’s bill to enter. Inside is a large amount of nectar stored specifically to fuel hummingbirds.
When hummingbirds insert their bill into the firecracker flowers, their forehead makes contact with the plant’s stamens. As the bird feeds, pollen is deposited on its head. When it flies to the next flower, this pollen rubs off onto the flower’s stigma to pollinate it. Without hummingbirds, firecracker bush would be unable to reproduce. This mutualistic adaptation demonstrates the vital co-evolution between hummingbirds and their food plants.
What behaviors do hummingbirds display when feeding from flowers?
Hummingbirds exhibit some interesting behaviors related to feeding on flowers:
- Territory guarding – Male hummingbirds are highly territorial and will aggressively defend nectar resources and flower patches from intruders.
- Traplining – Hummingbirds will visit familiar, productive flowers in a set order or circuit every day, like a trapline.
- Nectar robbing – Hummingbirds sometimes make small holes at the base of long tubular flowers with their beaks to rob nectar rather than pollinating properly.
- Perch feeding – At plants like aloe and agave, hummingbirds will perch on leaves and feed while remaining stationary.
- Piracy – Hummingbirds sometimes chase bees or butterflies from flowers to steal the nectar they have accessed.
Understanding these behaviors provides insight into how hummingbirds compete for limited food resources from flowers and maximize their energy intake throughout the day.
How does the partnership between hummingbirds and flowers vary by region?
The coevolution between hummingbirds and flowers has produced some distinct regional partnerships:
- North America – Ruby-throated hummingbird is the sole breeding species in eastern North America relying on native flowers like trumpet creeper, cardinal flower, and bee balm.
- Southwestern U.S. – Broad-billed, Black-chinned, Anna’s, Costa’s, and Rufous hummingbirds coexist and pollinate plants like ocotillo, prickly pear cactus, and chuparosa.
- Central America – Hermit hummingbird and its traplining behavior led to a coevolved trapline of matching flowers including Heliconia.
- South America – The aptly named Marvelous Spatuletail hummingbird coevolved with Centropogon nectar-producing flowers found in its small Andean range.
These partnerships demonstrate the regional diversity of hummingbirds and show how different species rely on the local flowers that have adapted specifically to their morphology and behavior in a given habitat.
Do hummingbirds compete with bees for nectar resources?
There is some competition between hummingbirds and bees when it comes to flower nectar. However, the two groups have also evolved to partition resources and minimize direct competition in many cases. Here are some key factors:
- Flower shape – Tubular flowers favor hummingbirds while more open, flat flowers attract bees.
- Color – Bees see yellows and blues best while hummingbirds prefer red/orange flowers.
- Nectar profile – More watery nectar benefits bees versus higher sugar content for hummingbirds.
- Body size – Tiny hummingbirds can access nectar from flowers bees cannot manage.
- Behavior – Hummingbirds are aggressive toward bees if defending a food source.
There are some cases of competition, such as both groups feeding from popular non-native plants. However, their adaptations generally allow hummingbirds and bees to successfully use different flower resources in the same ecosystem.
Do any plants mimic hummingbird flowers for pollination?
Some non-hummingbird pollinated plants leverage colorful tubular flowers to mimic those favored by hummingbirds and attract the birds for pollination. Two examples are:
- Indian paintbrush – These wildflowers have elongated red-orange tubes resembling hummingbird flowers. Hummingbirds will feed from them but the flowers are actually pollinated by bees and butterflies.
- Columbine meadow-rue – Unlike other columbines, this species has exerted stamens so hummingbirds brush pollen onto them while feeding. Bees do most of the actual pollination though.
Both of these plants essentially trick hummingbirds into stopping by using hummingbird-like flowers. The extra visitation still benefits the plants through the small amount of hummingbird-enabled pollination they receive.
How does habitat loss affect the hummingbird-flower relationship?
Habitat loss from human activities threatens many delicate pollination relationships, including between hummingbirds and the specialized flowers they feed on. Some specific impacts include:
- Removal of flowering plants critical to hummingbird food supply and energy needs.
- Fragmentation of habitats so hummingbirds cannot efficiently locate or access flower resources.
- Reduced gene flow and reproduction in plants due to lower hummingbird pollination.
- Increased competition pressure if remaining habitat cannot support as many hummingbirds.
- Introduction of invasive species that disrupt native plant-pollinator relationships.
Providing corridors between fragmented habitats and planting appropriate native flowers can help counteract these threats. Careful conservation practices are needed to preserve the ancient interdependency between hummingbirds and flowers.
How has photography advanced our understanding of hummingbirds feeding from flowers?
High-speed photography has revolutionized the study of hummingbird-flower interactions by revealing details impossible to see with the naked eye. Key discoveries enabled by photography include:
- The incredible speed of a hummingbird’s lapping tongue – around 10-15 licks per second.
- The nuances of pollen transfer to different parts of the hummingbird’s head and body.
- Behaviors like nectar robbing not visible through regular observation.
- Subtle variations in feeding strategies between different hummingbird species and flower types.
- Aerodynamic effects – photos of hummingbirds in flight around flowers informed new models of their energy efficiency.
Photography provides permanent visual records that can be studied frame-by-frame to elucidate the mechanics behind this mesmerizing pollination mutualism.
Conclusion
The relationship between hummingbirds and flowers exemplifies a spectacular case of coevolution. Attracted by energy-rich nectar, hummingbirds became expertly adapted to feed from specialized tubular blossoms. In the process, they took over an essential role in cross-pollination that ensures the survival and reproduction of many plant species. This delicate partnership evolved over millions of years and continues to shape the lives of both hummingbirds and flowers. Understanding these interactions provides key insights into the beauty and interconnectedness of life on Earth.
