Quick Answer
Yes, ruby-throated hummingbirds can and do pollinate flowers. As they feed on nectar from flowers, some pollen sticks to their heads and beaks and gets transferred to the next flower they visit, enabling pollination. Ruby-throated hummingbirds are important pollinators, especially for tubular-shaped flowers adapted specifically for pollination by hummingbirds.
Overview of Ruby-Throated Hummingbirds and Flower Pollination
The ruby-throated hummingbird (Archilochus colubris) is the most common and widespread hummingbird species in eastern North America. It gets its name from the vibrant metallic red throat patch found on the males. Ruby-throats have long slender bills that are perfect for reaching into tubular flowers and accessing the nectar inside. As they feed, pollen gets stuck all over their heads and bills. When they fly to the next flower, some of this pollen rubs off onto the flower’s stigma (female part) resulting in pollination.
Many flowers rely on ruby-throated hummingbirds specifically for pollination. These flowers are called ornithophilous flowers. They tend to be tubular in shape, often red in color, and hold their nectar at the far end of the flower, which is perfectly suited to the long bill of a hummingbird. Some common hummingbird-pollinated flowers include cardinal flower, trumpet vine, bee balm, and columbine. The shape and color of these flowers have evolved to attract hummingbirds. The birds have a poor sense of smell, so ornithophilous flowers tend to be brightly colored instead of strongly scented like bee-pollinated flowers.
Details of the Pollination Process
Here is a step-by-step look at how ruby-throated hummingbirds pollinate flowers:
1. The hummingbird is attracted to a tubular flower by its bright red color and flies over to feed on the nectar inside. As it sticks its long bill into the flower, its head and bill pick up pollen from the flower’s anthers (male part).
2. As the hummingbird feeds, pollen accumulates all over its head and bill. Ruby-throats have specialized feather structures to help pollen stick.
3. When finished feeding, the hummingbird flies off to find another flower with nectar. Some pollen falls off during flight, but plenty remains stuck to its head and bill.
4. At the next flower, some of the pollen is deposited onto the flower’s stigma as the bird sticks its bill inside for nectar. The pollen then germinates and travels down the flower’s style to fertilize its ovaries.
5. Fertilization leads to seed and fruit production, allowing the plant to reproduce. This is made possible by the hummingbird transporting pollen between flowers.
Why Hummingbirds are Effective Pollinators
There are several key reasons why ruby-throated hummingbirds are effective at pollinating the flowers they feed from:
– High energy needs – Hummingbirds have extremely high metabolisms and must consume large amounts of nectar each day (up to 2-3 times their body weight per day) to fuel their energy needs. This causes them to regularly visit many flowers each day seeking nectar, facilitating extensive pollen transfer.
– Bill shape – Their long, slender bills are specialized for nectar-feeding from tubular flowers. This brings their head and bill in close contact with the reproductive parts to enable efficient pollen pickup and transfer.
– Lack of pollen avoidance – Unlike bees, hummingbirds do not groom themselves to remove pollen, since it does not impact their ability to fly or feed. So pollen remains on their bodies to be transferred flower-to-flower.
– Flight agility – Hummingbirds can hover and fly backwards, allowing them to efficiently access nectar while maximizing pollen transfer. Their flight skills allow them to regularly access flowers in a pattern that facilitates cross-pollination.
– Color vision – Hummingbirds see color better than bees. They have excellent color vision which helps them zero in on the bright red tubular flowers that they coevolved with. This color vision also aids the birds in accessing nectar.
Other Pollinators
While ruby-throated hummingbirds are the most effective pollinators for ornithophilous flowers, other animals contribute to pollination as well:
Insects
Bees, wasps, butterflies, and moths will occasionally visit hummingbird flowers. They are attracted to the nectar and can transfer some pollen in the process. However, their bodies do not contact the reproductive structures as efficiently as a hummingbird’s bill does. So insect pollination is supplemental for ornithophilous flowers, but hummingbirds do the bulk of the work.
Other Birds
In some regions, other hummingbird species may visit and pollinate the same flowers that ruby-throats utilize. Selasphorus hummingbirds like the rufous hummingbird and Allen’s hummingbird on the West Coast can pollinate ornithophilous flowers. Orioles and certain other nectar-feeding songbirds may also occasionally pollinate. But in most of eastern North America, the ruby-throated hummingbird fills this specific niche.
Bats
In the southwestern United States, migrating Mexican long-nosed bats pollinate agave flowers. Agave flowers open at night which is better suited to nocturnal bat pollination than diurnal hummingbird pollination. But in most of the ruby-throated hummingbird’s range, bats are not significant pollinators of ornithophilous flowers.
Threats and Conservation
It is important to conserve ruby-throated hummingbird populations so they can continue providing vital pollination services to eastern North American flowers. Some threats to hummingbirds include:
– Habitat loss – Clearing of forests and meadows for development destroys crucial foraging and nesting habitat.
– Pesticides – Chemical contaminants can accumulate in the nectar and insects that hummingbirds feed on.
– Climate change – Global warming alters flowering times disrupting the synchrony between pollinators and flowers.
– Competition – Introduced species competing for limited nectar resources may impact ruby-throat populations.
Here are some tips for providing habitat to help hummingbirds:
– Plant tubular native flowers that provide nectar such as bee balm, trumpet creeper, and cardinal flowers.
– Avoid pesticide use in yards and gardens that hummingbirds visit.
– Install a hummingbird feeder with fresh sugar water (4 parts water 1 part white sugar). Change nectar every few days.
– Include flowering trees and shrubs that attract insects (food source) such as lilacs.
– Limit building in meadows, forests, and other natural areas to preserve habitat.
Conclusion
The ruby-throated hummingbird serves as an important pollinator in eastern North America, especially for tubular ornithophilous flowers that rely specifically on hummingbirds for pollination. As the birds feed on nectar, pollen sticks to their bill and head which then gets transferred to other flowers they visit, enabling cross-pollination between plants. Conserving hummingbird populations and their habitat is crucial for ensuring these tiny creatures can continue providing essential pollination services for beautiful wildflowers. With their high-energy lifestyle, specialized physiology, and precision flight, ruby-throated hummingbirds are perfectly adapted to pollinate the dazzling red flowers they coevolved with.
