Why did the Bird of Paradise flower evolve to look like that?
A Bird of Paradise flower from my walk this morning. (Photo: Shala Howell)
It’s easy to see how the Bird of Paradise flower got its name. Especially if you happen to walk by one at night. It really does look like someone crafted a tropical bird’s head out of flower petals.
Now, I’m no botanist, but anecdotal evidence from lots of visits to arboretums and botanical gardens in the past has taught me that when highly specialized and unique structures arise in plants, there’s generally a reason for it. And that reason often has to do with pollination.
Plants use their flowers to attract pollinators
Flowering plants need to move their pollen from one flower to the next in order to create the next generation.
Pollen typically doesn’t move on its own though. Plants rely on insects, birds, and even the wind to shift their pollen around to the necessary spots. As a hayfever sufferer, I try to ignore the wind’s role in these sorts of things. When I’m walking around the Outside World, I prefer to focus on pollinating agents that don’t make me sneeze, like bees.
It’s easy to see how a bee or a butterfly could pollinate a plant like the rose. After all, roses have a strong scent to attract the bee’s attention and short round petals which provide easy access to its nectar (and the pollen lurking nearby).
At first glance, though, a Bird of Paradise looks more forbidding and much less inviting.
So why did the Bird of Paradise evolve to look like it does?
The Birds of Paradise here in California all live in gardens. I don’t think I’ve ever seen a pollinator come near them. Instead, gardeners make sure the Birds of Paradise get whatever it is they need to keep blooming.
But what about in the wild? How do Birds of Paradise survive in their native habitat without gardeners to keep them fed and flourishing?
Wild Birds of Paradise are only found in subtropical parts of South Africa
Wild Birds of Paradise can only be found between the southeast KwaZulu-Natal and the south-central Eastern Cape provinces of South Africa.
I really wish I could claim to have just instinctively understood where that part of South Africa was, but I didn’t, so I tracked down a map. As you can see, the KwaZulu-Natal and Eastern Cape provinces are along the Indian Ocean coastline.
How does the Bird of Paradise survive in the wild?
Birds of Paradise rely on birds to spread their pollen. In their native habitat, that typically means the Cape Weaver, a type of sunbird that feeds on the rich nectar at the heart of the Bird of Paradise flower.
To reach the nectar, the birds must reach far down into the flower, at just the right angle. Conveniently, the Bird of Paradise has evolved to provide a handy perch that birds can rest on while they’re feeding. That’s part of what the blue petals are for.
While the birds are feeding on the plant’s nectar, anthers (the part of a flower’s stamen that contains the pollen) are thrust upward out of hiding by the bird’s weight. The anthers lightly brush the bird’s feet, coating them with pollen.
The next time the bird lands on a Bird of Paradise, it transfers that pollen to the new plant. Voila! Pollination achieved!
Remember when I said that I’d never seen a pollinator go near any of my local Birds of Paradise?
Apparently I just need to keep looking. While researching this post, I found this picture of a common yellowthroat warbler feeding on a Bird of Paradise in southern California.
Sure enough, he’s sitting on that handy blue perch.
The San Diego Zoo also has a picture of a hummingbird sipping the nectar from a Bird of Paradise on its website. With its long beak, the hummingbird doesn’t have to worry as much about achieving just the right angle to reach the nectar and so can feed while flying. Hummingbirds, apparently, don’t always pull their weight when it comes to helping the Birds of Paradise pollinate.
At any rate, I’m going to keep watching for birds near my local Birds of Paradise. If I see any, I’ll take a picture and post it here on Caterpickles.
Related Links:
- Bird Pollination of the Bird of Paradise (In Defense of Plants)
- Birds of Paradise (Teleflora Blog)
- Birds of Paradise (The Flower Expert)
- Efficient avian pollination of Strelitzia reginae outside of South Africa (Science Direct)
- Birds of Paradise (Animals and Plants at the San Diego Zoo)
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