The Science of Birds - Flowers and Feathers: The Importance of Birds as Pollinators

Episode Date: January 19, 2024

This is Episode 90 and it’s all about the importance of birds as plant pollinators.If I had to use only one word for the topic of this episode, it would be ornithophily. The definition of ornithophily is “the pollination of flowers by birds.”Today, I’ll be focusing mostly on the ecological relationships between plants and the birds that pollinate them. Another way to look at all of this would be through the lens of evolution—the fascinating ways that plants and birds have co-evolved with respect to pollination.I’ll make another podcast episode, at some point, about bird and plant co-evolution. We’ll touch on it today, but the main focus is ecology. Pollination ecology is actually an entire subdiscipline that many scientists have dedicated their careers to studying. It’s really interesting stuff!  ~~ Leave me a review using Podchaser ~~Link to this episode on the Science of Birds website Support the show

There's a group of flowering plants in Australia called Banksias. They're icons of wild places, what Aussies call the bush, as well as suburban flower gardens. Australia is home to about 150 plant species in this group. They're called Banksias because they're all in the genus Banksia. If you live in Australia, you know what these things look like. For the rest of us, to describe a typical Banksia flower, well, it's got a distinct and eye-catching appearance. The flower head is large with a cylindrical or cone-like shape. The color ranges from pale yellow to deep red or brown. The individual flowers

are small, tubular, and packed tightly together. Many Banksia species are quite beautiful, and that explains their presence in city parks and gardens. Banksias are important members of Australian ecosystems. The flowers pump out lots of sweet nectar. This sugary liquid is a food source for all sorts of critters, bees and other insects, bats, rodents, and possums. Oh yes, and birds. Birds in the honey eater family, Melophagody, are one of the best examples.

These guys love slurping up the honey, more accurately called the nectar of Banksia flowers. One of my favorite Australian bird species is the New Holland Honey-Eater, Philodonorous Novi-Halandi. Why New Holland? Because before the land down under was named Australia, its original European name was New Holland, given to it by the early Dutch explorers. The New Holland Honey-eater is a medium-sized songbird with mostly black plumage, but it's got bold black and white streaking on its breast, bright patches of yellow in the wings, and eyes with striking white irises that really pop against the black facial feathers.

The beak is long and slightly down-curved. I fell in love with this bird while leading a birding tour in Tasmania. They were all over the place, and I got to see them feeding from Banksia flowers, which was fantastic. Now, if I do some quick math here on my notepad, X number of honey eaters divided by the radius of the sun, square root of 42, carry the zero. Okay, based on my calculations, New Holland honey eaters have guzzled exactly 3.2 billion gallons of Banksia nectar

over the last 10,000 years. In exchange for receiving all that sugary sustenance from the plants, the birds have been providing the service of pollination. They're vitally important pollinators for Banksia's and other Australian plants. This pollination partnership between birds and plants in Australia is just one example among thousands found across the world. Hello and welcome. This is the Science of Birds. I am your host, Ivan Philipson. The Science of Birds podcast is a lighthearted exploration of bird biology for lifelong learners.

This is episode 90, and it's all about the importance of birds as plant pollinators. If I had to use only one word for the topic of this episode, it would be ornithophily. The definition of ornithophily is the pollination of flowers by birds. But just FYI, if you look at the breakdown of the word ornithophily, at the origin of its parts, you see that it literally translates to the love of birds. Well, isn't that nice? The love of birds. Getting back on track, today I'll be focusing mostly on the ecological relationships between plants and the birds that pollinate them. Another way to look at all of this would be through the lens of evolution,

the fascinating ways that plants and birds have co-evolved with respect to pollination. I'll make another podcast episode at some point about bird and plant co-evolution. We'll touch on it today, but the main focus is ecology. Pollination ecology is actually an entire sub-discipline that many scientists have dedicated their careers to studying. It's really interesting stuff. When birds like the New Holland honey eater pollinate plants, they're performing something scientists call an ecosystem service.

An ecosystem service is a benefit that we humans receive from nature. Birds provide the ecosystem service of helping plants reproduce. They help to maintain natural ecosystems by propagating native plants. birds do this through not only pollination but also by seed dispersal. Birds are great at spreading seeds around. Now, I don't know about you, but I have to remind myself sometimes that the only reason that flowers, with all their captivating colors and scents, the only reason they evolved on earth, at least originally, was to attract pollinators.

The first plants with flowers, the angiosperms, appeared roughly well. 140 million years ago. Insects were probably the first animals that flowers attracted as plant pollinators. Bats are another major group of animals that pollinate plants. They first appear in the fossil record about 50 million years ago. From around that same time period, 50 million years ago, is when we have the earliest evidence for birds sticking their beaks into flowers. There's a fossil, found in Germany, of a wren-sized bird named Puliornus Tessalatus. Preserved in the fossil are a bunch of pollen grains in the bird's stomach. So birds have been interacting with flowers for at least 50 million years. Today, pollination is performed more commonly by insects than birds. But it turns out that birds,

in many cases, might be more effective than insects in their roles as pollinators. We'll talk about why in today's episode. But first, how about we stop and smell the roses? Let's talk botany. For a plant, making nectar is costly. It takes a lot of energy. So a plant doesn't fill its flowers with sweet liquid just for the heck of it, or just to selflessly offer a meal to a poor, hungry bird.

No, the plant has more of a what's in it for me attitude. Imagine we've got a bird, let's say a hummingbird. And it's attracted to some bright red flowers. The hummingbird wants some tasty nectar, so it uses its long, long bill to probe deep into a red flower. The flower petals on this plant are rolled together into a tube shape, and the nectar is pulled up at the closed end of the tube. Also inside the tube are the flower's reproductive parts. Running along the central axis of the tube is the female structure, the pistol. No, not pistol, pistol, P-I-S-T-I-L. Surrounding the pistol are several to many

stamens. These are the flower's male structures, the pollen-making structures. As our hummingbird pushes its cute little face into the flower to get at the nectar, it inadvertently rubs some of its head feathers against the business end of those stamens. In other words, the pollen-bearing tips of the stamens, which are called anthers. A bunch of tiny pollen grains end up stuck to the feathers. Then the hummingbird flies off to another patch of the same red-flowered plant. It buzzes in close to slurp up some nectar from one of these new flowers. As it does, those hitchhiking pollen grains from earlier come into contact with the female part, the pistol. And just like that, pollen has been transferred from the anthers of one plant to the pistol of another. Great success. Now, plant

reproduction, fertilization, all of that kicks into high gear. The hummingbird has, as far as the plant is concerned, accomplished the one and only thing it's good for. Some plant species depend entirely on one bird species for their pollination, or at least on one type of bird, like hummingbirds, sunbirds, or honey eaters. Specialized plants like these usually have co-evolved with their avian pollinators. The evolution of the plant to facilitate pollination has influenced the evolution of its pollinators, and vice versa. The term used for specialized plants like this is or ornithophilus. They love birds, and birds love them. Plant and pollinator have been dancing together through the process of co-evolution across the millennia, shaping each other

generation after generation. Today, there are ornithophilus plants that have independently evolved in many plant families around the world. For example, if we consider only the plants that depend on hummingbirds as pollinators, we're looking at more than 7,000 species from among 68 plant families. A few types of plants with ornithophilus representatives are fuchsas, agaves, begon honeysuckles, penstemens, lobelias, monkey flowers, and gillias. Many of the flowers on these plants share certain traits, traits that are great for birds, but lousy for insects. These include red tube-shaped flowers, not much of a scent, and nectar that's rich in sucrose. The nectar is often secreted during the day when flower-visiting

birds are active. A bird typically has to reach deep into the flower tube to reach the nectar. This ensures that some pollen gets dusted onto the face and head of the bird. Insect pollinators like bees prefer blue, purple, or yellow flowers, and they prefer nectar made of fructose and glucose rather than sucrose. Also, the petals of ornithophilus plants don't have any little landing pads, the way that many insect-pollinated plants do. It's as though ornithophilus plants roll out the red carpet for birds, almost literally. But when it comes to inquisitive insects, these same plants have rusty chain-link fences surrounding them, posted with no trespassing signs, and sitting on the porch is a grumpy old man with a shotgun in his lap.

He's like, get off my lawn, you filthy good-for-nothing bugs. Ornithophily is one of several pollination syndromes. Another syndrome is entomophily, which is, you guessed it, pollination facilitated by insects. Each syndrome is a suite of flower traits that are strongly associated with a particular mode of pollination. One drawback of being a plant with the pollination syndrome of ornithophily, enticing birds with nectar, is that birds can be kind of rough. Birds will sometimes treat a flower the way a two-year-old human treats a birthday cake. There's no decorum, no gracefulness. They just dive in face first to get the sweet treat. The result is utter devastation. But seriously, birds can,

in their childlike exuberance, injure the delicate reproductive parts of a flower. By some estimates, more than half of the world's ornithophilus plant species have evolved flower architectures that help to prevent being injured this way. For example, the ovary of the flower might be positioned deep beneath the pool of nectar, so that it stays clear of the bird's pointy, stabby beak. Okay, so that's a little about ornithophilus plight. plants. Many other kinds of plants are visited by a mixture of pollinators, birds, insects, maybe bats, rodents, etc. These plants are unspecialized. They're not ornithophilus. The Banksia flowers I mentioned earlier provide one example. The saguaro cactus is another great example.

This iconic plant of the Sonoran Desert in North America has large white flowers that are visited by bees, bats, and birds. The primary avian pollinator is the white-winged dove. Other birds that sip nectar from saguaro flowers include Costa's hummingbird, black-chinned hummingbird, hooded oriole, Scots' oriole, Gila woodpecker, gilded flicker, and verdin. Like plants, some birds in the pollination game are specialists. Others are generalists.

Some are very selective in the flowers they visit, while others slurp nectar wherever they find it. Those latter generalist birds would probably just as happily drink nectar out of an ashtray or an old leather boot if you give them the chance. I mean, that's just a hypothesis, of course. More research is needed. We've been talking about birds, sipping nectar. A bird or other animal that gets all or most of its daily calories from sugary nectar like this is called a nectarivore. This way of feeding has evolved multiple

times, independently among various branches on the tree of life. Nectarivorous birds share several features. These are adaptations to their flower probing, flower diving way of life. Long Bills are typical of these birds. Often the bill curves downward to some extent. The tongue is long too. It's used for lapping up nectar. The tongues of many nectar-riverous birds have brushy tips. They have a lot of surface area. All the better for sopping up liquid. Some nectar avores have even more specialized tongues. The structure of their tongue allows it to work sort of like a tiny straw or like a pump for sucking up nectar. This is true for hummingbirds, for example. The ability to hover in flight is also a helpful adaptation for feeding from flowers.

That said, some bird-pollinated plants go so far as to provide a nice little perch for a visiting bird, a perch that positions the bird at just the right height and angle to maximize the exchange of nectar and pollen. No hovering necessary. The quintessential nectar avores are, you know it, hummingbirds. They've got the long bills and tongues, and they've got the superbly well-developed ability to hover. Check out episode 8 of this podcast if you want to learn more about hummingbirds. Other birds that heavily depend on nectar include sunbirds, see episode 81, many honey eaters, sugarbirds, sunbird assities, and Hawaiian honey creepers.

Hummingbirds and those groups I just listed are the dedicated avian nectarivores. They're more specialized, but many other birds in the world will dip their beaks into flowers, at least occasionally. They supplement their diets of insects or fruit or whatever with a little nectar here and there. Examples of birds whose diets include nectar, at least sometimes, are white eyes, flower peckers, leaf birds, honey creepers, and flower piercers in the Tanager family, New World Orioles, some songbirds in New Zealand like the Stitchbird and North Island Coca-Co, and, last but not least, the lorries, which belong to a sub-family of the old-world parrots.

So, all in all, just how many of the world's approximately 11,000 bird species visit flowers to drink nectar, and therefore probably act as pollinators? I can't give you an exact number, but one estimate is that about 20% of bird species visit flowers, at least occasionally. So that would be roughly 2,000 bird species. But if we consider only the bird species that are truly dependent on nectar, the ones that visit flowers day after day, there are perhaps 900 to a thousand species in that category. Geographically speaking, specialized nectar-riverous bird species and their ornithophilus plant counterparts are more common in the world's tropics, in southern Africa, and on some groups of islands. Non-specialized plants that get visited by birds are found more widely across the globe.

But in most regions, these plants represent only about 5% of the local flora. That percentage is a bit higher on islands, around 10%. Interestingly, Australia has a higher proportion of plants that get visited by birds, about 15% of species. These are plants like Banksia, eucalyptus, and the bottle brushes in the genus Callistamine. I'm not sure anyone has a great answer yet for why Australia's plants get visited by birds so often, but I'll come back to this question in a moment. One more thing I want to add here is that, in general, these intimate plant-bird partnerships we're talking about are also more common in certain environments, such as at high elevations and in deserts, places where insect pollinators are more scarce.

And this leads us further into the differences between bird and insect pollinators. Ah, yes, birds versus bugs, the bitter and age-old rivalry between pollinators. The inspiration for many a song and for epic poems recited by the ancient. Some say that the six-legged arthropods are nature's most skillful pollinators. Others hold to the opposing view, that small-feathered dinosaurs are, in fact, the best creatures when it comes to the task of moving pollen to and fro. As the host of a podcast named the Science of Birds, I have no choice but to take sides and place myself firmly in the Birds Are Better Camp.

Such is my fate. But as a scientist, I'm not comfortable making bold claims and just leaving it at that. No, I have to back up my claims with data and facts. So I'll offer you a few reasons why birds are, or at least might be, more effective than insects in their roles as pollinators. Reason number one. Compared to insects, birds might be more reliable as pollinators. in certain environments. With their hot little endothermic bodies,

birds can actively visit flowers even in cold and wet weather. They can even pollinate plants in the winter. For example, there's a hummingbird species called the Ecuadorian hill star, Oreo Tricilis Chimborazo. It lives high in the Andes at elevations up to 17,000 feet

or 5,200 meters. As you can imagine, it can get pretty chilly up there. This tiny bird, the Ecuadorian hill star, gets most of the nectar it needs from a beautiful shrub in the sunflower family called Chukiraga. In English, it's sometimes called the flower of the Andes. Also, Chukiraga is Ecuador's national flower. Birds may serve plants better than insects in environments that are cold, like the high Andes. and also in regions with highly unpredictable climates and unpredictable flowering seasons. This might explain what's going on in Australia.

The efficiency of birds as pollinators in unpredictable environments might be part of the reason that so many Australian plants are swarming with nectar-swilling birds. Another part of the explanation could be that because many ecosystems in Australia have abundant sunlight and warmth, The plants there have no shortage of energy. As long as the plants have enough water, they can use that energy to secrete ridiculous volumes of nectar, to bring all the birds to the yard, so to speak. Reason number two for why birds are better pollinators. There's scientific evidence that pollination by birds

can result in plants producing more seeds or fruit. This comes from experiments on plants that, in natural conditions, get visited by both birds and insects. If insects are experimentally excluded from the flowers, but birds are still allowed to do their thing, and the opposite condition is also tested, the plants pollinated by birds in many cases make significantly more seeds. Scientists look at this phenomenon, called seed set, because it tells us about the real effectiveness of pollinators. A bee or a bird just visiting flowers and slurping some nectar or whatever, a visit doesn't necessarily result in actual pollination. But by counting

the numbers of seeds a plant produces after being visited by one pollinator or another, we get a better sense of which animal has the best ability to move pollen between plants. Why might birds be more effective at transferring pollen. Well, let's look at bees. Bees are among the most numerous and important insect pollinators on the planet. But those little buggers not only drink nectar, they also eat pollen. That's how they get their protein, fat, and vitamins. While a bee is flying from one plant to another, it grooms itself, scraping off a lot of the pollen from its fuzzy little body. The bee either eats the pollen or stores it in the pollen baskets on its hind legs. Stored pollen gets taken back to the colony to feed other bees and the larvae. That means

there are fewer pollen grains available to pollinate the next plant. But many birds are a lot less interested in pollen as a food source. If anything, they probably find pollen annoying. All a bird wants is some sweet, sweet nectar. But after plunging its beak into a flower, the bird's face and head are now covered in little yellow pollen sprinkles. It's like when I go up into the attic to find the box of my old stuffed animals, my childhood friends, because, you know, I'm having a hard day at work, and I just need someone to talk to and to hug. Maybe I'd like to have a little tea party with my stuffed animals. But after I crawl through the attic, now I'm covered in dust and spiderwebs.

Ew. Maybe that's how some birds feel about pollen. They're like, gross, I'm covered in icky pollen. Get it off me. Get it off. Well, however they feel about it, the fact that birds don't eat much pollen makes them better at transferring the stuff between flowers. Reason number three for why birds are better pollinators.

Birds do a better job of helping plants avoid inbreeding. Some plants can self-pollinate. Pollen from one flower on an individual plant can end up fertilizing another flower on the same plant. Without the help of a pollinator, this could happen because of gravity, the wind, or because the flowers accidentally rub against each other. Self-pollination can lead to inbreeding, and in-breeding leads to genetic, problems for the offspring. Genetic problems lead to fear. And, hey, Yoda, how does the rest of it go? Fear leads to anger. Anger leads to hate. Hate? Leads to suffering. Ah, yeah, got it. Thanks.

The point is that inbreeding leads to suffering. Offspring from inbreeding are often less healthy, less likely to survive. Insect pollinators like bees like to move methodic methodically from flower to flower on the same individual plant, so they can sometimes be the cause of self-pollination and inbreeding. Birds, on the other hand, usually move frequently between different individual plants, so they help plants to cross-pollinate rather than self-pollinate. And birds fly greater distances between plants. Distantly separated plants of the same species are not,

likely to be close relatives. Cross-pollinating over large distances, therefore, helps minimize in-breeding. This brings us to the concept of gene flow. Gene flow is the transfer of genes between populations. It can happen through the movement of migrating individuals, or, in the case of pollen, of genetic material from one population to another. Birds, which their relatively high mobility are way better than insects at maintaining high levels of gene flow among plant populations. High gene flow is good because it helps to maintain genetic diversity. It reduces inbreeding, and it may improve a plant species' ability to adapt through natural selection. Birds maintain gene flow not only because they fly longer distances

compared to insects, but also because birds live longer and have better spatial memories. They remember where each little flower patch is across sometimes vast distances. For these reasons, birds can move pollen between small patches of plants separated by major barriers like mountain ranges or deserts. Birds are such awesome pollinators that scientists have discovered cases where a bee-pollinated plant has switched through evolution to become bird pollinated. I'll put a link in the show notes to an interesting paper that shows this for some plants in North America. It was published in 2022 in the journal Ecology and Evolution.

The study focuses on several plants that switched from being entomophilus to ornithophilus. Long ago, these plants were pollinated by bees, but now they're pollinated by humming birds. The researchers ran experiments, and they found that these hummingbird pollinated plants have low seed counts and low germination rates when they self-pollinate. Bees, as we know, are more likely to cause self-pollination. It seems these plants really thrive only when they cross-pollinate, and it's the hummingbirds that can make that happen. So, in conclusion, birds are going to great, and insects are the worst, especially bees. Just kidding. I love bees and other insects, too. They deserve our respect for sure. But it's true that birds are more efficient as pollinators

in certain environments and for certain types of plants, like the ones that can't successfully self-pollinate. However, to be fair, one realm where insects shine is in agriculture. Insects perform the vast majority of pollination for our domesticated crops, especially bees. I'm sorry to say that birds don't do a lot to help in the production of agricultural plants like fruits, veggies, and all that good stuff. So, if you like to eat food, thank a bee the next time you see one. A sad reality of our times is that bird populations are dwindling and their ranges are contracting in many parts of the world. No thanks to human progress. If birds are such important pollinators for many plants, what happens when birds disappear? What happens to plants and ecosystems when

avian pollinators are no longer around to offer their ecosystem service? Well, it depends, and certainly more research is needed to truly answer that question. Most plants are not dependent on a single bird species for pollination. If one avian pollinator disappears from the local ecosystem, another one might be able to pick up the slack and help to pollinate the same plants. One example comes from Hawaii. There's an endemic plant there called IAEA in the Hawaiian language. Its scientific name is fracinetia arborea. It grows as a woody vine. Once upon a time, the flowers of the IAEA were pollinated by native birds called Hawaiian honeycreepers, as well as the Hawaiian crow. The Hawaiian crow is now extinct in the

wild and dozens of honey creepers, more than half of the known species were driven to full extinction by humans. But the EAEA lives on. These days the plant is pollinated by a non-native bird that humans introduced to the islands, the Japanese white eye. So with the loss of some avian pollinators, another species stepped in to sort of fill the same role. The plants that might do OK in the absence of birds are the ones that get visited by a variety of pollinators, birds, insects, and mammals, like the Banksias and the saguaro cactus I mentioned earlier. These plants aren't overly ornithophilus. If the local bird pollinators disappear, these plants might still be able to reproduce with the help of insects. Honeybees, for example, are now found in many habitats. Some scientists

think the honeybee is one of the most likely insects to fill the void to replace the missing avian pollinators. But as we've already established, bees are the worst. So maybe they can never truly replace the lost birds in the pollination game. Bees aren't as good as birds when it comes to promoting cross-pollination. They gobble up a lot of the pollen instead of transferring it, and they don't fly as far as birds. But who knows? There was one study that revealed what happens to plants when bird pollinators disappear.

It was published in 2011 in the journal Science. The researchers looked at a small shrub in New Zealand with the scientific name, Rabdofamnus Solandri. They studied populations of this plant both on the mainland of the North Island as well as on three small islands. islands that just happen to be bird sanctuaries.

Many bird populations on the mainland of New Zealand were wiped out in the last 200 years. So, compared to the mainland, there are more native bird species like the bell bird and the stitch bird hopping around on the three small islands. These are birds that pollinate the rhabdofamnus shrubs. The researchers in this 2011 study found that the shrubs on the small bird, infested islands produced way more seeds and had more surviving seedlings. So that's pretty interesting. In the worst-case scenario, a plant species dependent on birds for pollination might go extinct if birds are no longer around.

However, and I guess thankfully, I'm not sure if there are any concrete examples of this happening yet. But some scientists have turned, once again, to Hawaii. to see what the loss of all those honey creepers has done to the native plants of the islands. At least 31 species of bird-pollinated plants in the family Campanulaceae have gone extinct in the last 200 years or so. It seems likely that their extinctions resulted from the loss of the pollinators. I don't know about you, but I, find that there's something heartwarming about the idea of a colorful little bird getting a

belly full of sugary flower nectar in exchange for helping some plants reproduce. It's a win-win situation. The bird wins and the plant wins. And I win too because the whole thing makes me happy. The kind of pollination we've been talking about is an example of a more general phenomenon in the biological world called mutualism. This is what biologists call an interaction between two species where each of them gets a net benefit from the interaction. Another example of mutualism is the relationship between birds called oxpeckers and large mammals in Africa.

The oxpeckers eat parasites like ticks on the skin of megafauna like zebras, rhinos, and buffalo. The bird gets some tasty treats, and the mammal gets some parasites removed. Mutualisms like these contrast with interactions between species like competition and parasitism. In the latter situations, there's usually a winner and a loser. So the plant bird mutualism we see in pollination is a lovely thing. But there's also a dark side to this. The pollination story is not without its villains.

There are some dastardly bird species out there that have taken the low road. They don't want to play by the rules of mutualism. These birds drink nectar from flowers, but they don't pollinate the flowers. That's right. Some bird species make a living stealing nectar while. avoiding the pollen-bearing anthers of a flower. When birds surreptitiously slurp nectar and bypass the pollen without doing any further harm, we call them nectar thieves. But we call them nectar robbers if they tear a hole in the flower, damaging it to get at the nectar. A nectar robber

leaves a mess at the scene of its crime. And if a bird ambushes a flower in a dark alley, flashing a knife and saying, Just give me all your nectar and no one gets hurt. Come on, make it quick. Well, that bird we would call a nectar mugger. Nectar robbers and thieves exploit the plant pollinator mutualism. But in reality, their acts of floral larceny don't come from any bad intentions. They're not really villains.

These birds are just following their instincts and doing what they can to survive. Nectar robbing among birds is more common. with plant species that have long tube-shaped flowers. Such flowers are meant to be pollinated by long-billed birds like hummingbirds. Nectar robbing birds have shorter bills that can't reach all the way down to the nectar at the base of the tube. So the bird goes around to the outside of the flower instead to the base of the petals and punches a hole through them.

It pushes its beak and tongue through the hole to access the pool of nectar. and it's not likely in this maneuver that any pollen ends up stuck to the bird's feathers. So just who are these flower plunderers, these blossom pirates? Well, we see this behavior among a number of bird families. Some hummingbird species, the ones with shorter bills, are nectar robbers. And small songbirds like New World Warblers will sometimes steal nectar, and so will New World Orioles. But perhaps the most notorious nectar robbers are the 18 bird species in the genus DiGlossa.

These are the aptly named flower piercers. They form a specialized group within the neotropical Tanager family, Thraupidae. Flower piercers live at high elevations, from Mexico down to Argentina. Flower piercers are easily recognized by their peculiar bill shape. The bill is narrow, slightly upturned, compressed from top to bottom, and there's a small hook at the tip of the upper bill. That hook is used to hold a flower steady while the shorter lower bill stabs into the flower petals.

Then the bird uses its specialized tongue to reach through the hole to the nectar. As I mentioned, the 18 flower piercer species all belong to the genus Diglossa. This word translates as double-tonged. The tongue of flower piercers is like an upside-down U-shaped trough or channel. It splits near the end into two smaller channels, each with a brushy tip, perfect for lapping up nectar. After the hole is punched into a flower, flower piercers may revisit it to keep lapping up nectar as it gets replenished. Now, I know I said that nectar robbers aren't really villains, but there's one species in the genus DiGlossa named the masked flower piercer.

Its body is a rich blue color, but it's got red eyes and a black mask on its face. Like, I don't want to judge a book by its cover, but are you trying to look like a criminal bird? I mean, you've got scary red eyes staring out from behind a black. black mask. I'd be terrified if I saw you in a dark alley. Flowers damaged by nectar robbers like the masked flower piercer may have shorter lives than intact flowers. And flowers with holes punched in them can be less attractive to honest law-abiding pollinators. So, nectar robbing deprives plants of pollination in more than one way. When it comes to birds and pollination ecology,

biologists used to focus their attention on the tightest associations between specialized ornithophilous plants and their pollinators. These relationships are, after all, pretty fascinating. The co-evolution of bird beaks that fit into flowers like a lock and key mechanism is an amazing thing. But we now know that bird pollination is a more widespread phenomenon. It's not limited to tropical ecosystems or to specialist nectar river as birds. There are many generalist plants and birds around the world that also have mutualistic relationships.

Insect pollinators are, yes, more common. But it turns out that under certain conditions, birds can be much more effective as pollinators. In any case, we can thank birds for the valuable ecosystem service they provide, for helping our native plants to reproduce and thrive. And that, my friends, wraps up episode 90 of the Science of Birds podcast. I hope you enjoyed learning a little about ornithophily today, about bird pollination. Since the last episode, the newest supporters who have joined my Parenthood, Patreon community are

Susie Reddy, Liz Clinton, Paula Carr, Dr. Janet DeGiorgio Miller, Kelly Seneke, Stephanie Carter, Rebecca Leadam, D.N. and pessimistic corn. Welcome and thank you all so much for the help. And thanks very much to all my other patrons who've been with me for a while. If you, dear listener, are wondering how you too

can help me to keep making this podcast, You can check out my Patreon page over at patreon.com slash science of birds. There's a link in the show notes as well. You can also shoot me an email if you have something you'd like to share with me. Maybe some words of encouragement. Or maybe you want to tell me what kind of stuffed animals you talk to when you've had a hard day at work. In any case, my email address is Ivan at scienceofbirds.com. This again is episode 90.

9.0. We're closing in on 100, you guys. You can check out the show notes for the episode, along with some curated photos of species I talked about today on the Science of Birds website, scienceofbirds.com. And don't forget, I've got a little shop on the website where you can order some fun Science of Birds merch like t-shirts, posters, and stickers. This is Ivan Philipson, wishing you a glorious day. Peace. Thank you.