Pollen grains cannot transfer themselves to the stigma of other plants or flowers without external factors such as being blown by the wind or being carried by insects.
Without this assistance, pollination would not take place and the reproduction of plant life would not be possible. We all know the importance of bees in pollination, but do birds help pollinate plants too? Keep reading to learn more.
The role of birds as pollinators is often overlooked in favor of that of bees, which many may give sole credit to for spreading pollen and aiding plant reproduction. But birds also play a key part in carrying pollen between flowers as they chase insects or drink nectar.
Pollination carried out by birds is known as ornithophily. Nectar-eating birds, such as hummingbirds, honey-eaters and sunbirds are crucial to the ornithophily process. As a bird feeds on nectar from a flower, pollen sticks to its beak as well as feathers around its head and back. This pollen is carried to the next flower it visits, where it rubs off and pollination takes place.
Although birds do play a substantial role in pollination, just how valuable is their contribution to the annual crop cycle of the plants rely on in our own diets?
Pollination of certain plants, including a large percentage of commercially grown crops, depend on bees rather than birds to successfully produce fruit and vegetables each year, and any role played by birds is considered incidental or relatively minor.
To find out how birds match up to bees in the pollination stakes, please keep reading.
Hummingbirds are one of the crucial species when it comes to ornithophily (pollination by birds)
Pollination is the transfer of powdery pollen grains (or seeds) from the male part of a flower (the stamen) to the female reproductive organs of another flower (known as the pistil, which is made up of the stigma, style and ovary).
Fertilization occurs when the pollen grain is transferred to the receptive surface of the stigma of a flower, which then ultimately leads to reproduction of more plants.
Birds that feed on flowers, nectar, and berries, or even those that perch in flowering plants or blossom on trees all aid the pollination process in a crucial way. Each time a bird comes into contact with a flower, pollen grains rub off on its beak, feathers, and feet. These grains are then carried to the next plant that they visit, where they are transferred and pollination occurs.
Birds that feast on nectar play a vital, direct role in the pollination of thousands of wildflowers, stopping to drink nectar from deep inside long, tubular flowers with their needle-like bills, and transferring pollen grains at every new flower they feed from. Flowers with red petals, especially, are attractive to hummingbirds.
Rufus hummingbird feeding on flower with pollen on it's beak
Nectar-eating birds are leading pollinators, with hummingbirds passing from flower to flower to satisfy in search of the sweet solution that meets the energy needed to maintain their incredibly fast metabolism.
Similarly, honey-eaters and sunbirds also aid the pollination process, visiting flowers for nectar and transferring pollen as they stop to feed. Other bird species – orioles, finches and some woodpeckers – also occasionally eat nectar.
Not eating nectar does not rule a bird out of the pollination process, and there are more than 2,000 bird species that are classed as pollinators in some form or another. Rainforest parrots, such as lorikeets, eat fresh flowers and transfer pollen grains every time they find a different food source.
Birds that eat vegetable crops also play some role in their pollination, spreading the pollen their flowers produce from plant to plant.
Birds that eat insects off flowers also make a vital contribution to pollination, perhaps unintentionally, brushing against flowers when catching bugs, and moving any tiny pollen particles as they move between blooms.
Sunbirds are also important in the pollination process
According to research, honey bees are responsible for pollination of around 80 percent of all crops worldwide, including fruits, vegetables, and nuts. With the ability to visit more than 1,500 flowers each day, bees are well deserving of the Top Pollinator crown.
While birds play an important role in the pollination of thousands of plants from around 60 wildflower families, there are no commercially grown crops that rely on ornithophily (pollination by birds). However, birds are vital to the survival and dispersal of many plant species, with approximately 8,000 plants in the Americas depending on pollination by hummingbirds.
Eastern Spinebill feeding on nectar, Australia
The contribution of bees to the pollination of a number of plants that are vital to the survival of thousands of bird species cannot be denied. Birds that feast on fruits and berries benefit directly from successful pollination that has been enabled by bees flying between the flowers of fruit trees and shrubs.
Without bees, the survival of thousands of plant species and diversity of landscapes around the world would fall into severe decline. This would inevitably have a negative knock-on effect on the future of birds with reduced food sources and degraded habitats to live and forage in.
Bees form an important part of the diet of some birds, particularly bee-eaters, thrushes and swifts. Woodpeckers also target hives if the opportunity arises, while bee larvae form an important component of a honey buzzard’s diet.
It should come as no surprise that Bee-Eaters eat bees as part of their diets
Berry-eating birds can take a huge amount of credit for helping pollination of many fruit trees and the dispersal of seeds over wide areas of land.
When birds eat berries and other fruit, any seeds they swallow are later defecated out onto the ground, where they stand a chance of taking root and developing into plants.
Migratory birds have the capacity to carry seeds in their digestive tract over long distances, with research showing seeds being pooped out over 300 km (190 mi) from their origin.
One particularly interesting example is the cassowary, which is a champion for dispersing a wide range of seeds throughout its rainforest habitats.
As cassowaries can eat plants that other species avoid, such as poisonous plants and fruits with large, indigestible seeds, such dispersal is especially important for ensuring diversity and species renewal that would otherwise not take place.
Close up of a Cassowary
Honey bees are by far the leading pollinators of fruit trees, recognized for pollinating more than 90 percent of the world’s commercially grown fruit crops, with apples, pears, cherries, peaches, plums, and mangoes all depending on bees to visit and carry their pollen to other trees.
For many fruit trees, birds are also an important catalyst of pollen transfer, transferring pollen from blossom to other fruit trees that may be some distance away.
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