Why do hummingbirds like red flowers?

The flowers of hardy Fuchsia above illustrate qualities that hummingbirds look for: red blooms and deep, dangling flowers that offer insects no place to land. Note the long stamens that protrude from the center of the flower: These will brush the hummingbird's head with pollen when the hummingbird sticks its head in the flower in search of nectar.

FIRST I SHOULD ADMIT that nobody knows for sure that hummingbirds do prefer red flowers. I've heard evidence on both sides, but I think the majority believe that hummers are more attracted to red and orange than to other colors. If true, why would this be? The short answer: Probably because animals prefer to avoid competing with each other for food. (It's hard enough to find food without having to worry that some other critter is going to empty the grocery store first.)
Now the long(er) answer:

Pollinators (animals that feed themselves by visiting nectar-producing flowers) would rather not compete over the flowers they visit. So, during the hundreds if not thousands of years that they've been visiting plants in search of nectar, they and the flowers have worked out a sort of deal: Whereas some flowers are specially suited to butterflies, others are specially suited to hummingbirds (others to moths, others to very small flying insects, and some even to bats).

So why would a hummingbird flower be red? Because insects don't see red very well.

Because insects don't see red well, they're more likely to skip red flowers, leaving more nectar in the red flowers for the hummingbirds to find. In contrast, hummingbirds do see red well. So a red flower is a sign that says to a hummingbird, "Not many insects have been here. More food for YOU!"

Color isn't the only way hummingbird plants discourage insect visitors in order to attract more hummers. Many hummingbird plants have flowers that are long and tube-shaped and that dangle downward. A hovering hummingbird, with its long tongue, can get nectar out of one of these flowers. Many insects cannot.

Mind you, the flowers are not doing this for free. If you look closely at a typical hummingbird flower (e.g., the hardy Fuchsia above or the Crocosmia "Lucifer" shown with the post below this one), you'll see that there are filaments sticking out of the center of the flower: These are stamens, and they have pollen on them. When the hummingbird sticks its head into the flower in search of nectar, the stamens will brush against the hummer's head, covering it with pollen. The hummingbird will then carry this pollen to the next flower it visits, pollinating that plant. (And that, ladies and gentlemen, is what we mean by "the birds and the bees.")

Incidentally, hummingbirds are gas guzzlers compared to insects. As a result, flowers that want to attract hummingbirds often have a big payload of nectar hidden away inside them. This gives the hummers another reason to look for the flowers that are saying "hummingbirds wanted here": The chances of a getting a good meal are ESPECIALLY good there. (Hummingbird flowers: the truckstops of the flower world.)

Why would the plant go to all this trouble? If the plant wants to reproduce, its pollen must be delivered to another flower of the same type. (A Crocomia wants its pollen to go to another Crocosmia, for example.) If the hummingbird is happy with the nectar it finds in one plant's flowers, the hummingbird will probably keep visiting flowers of the same type, greatly increasing the likelihood that all the flowers of this type will be pollinated.


Alek said...

Thanks for this interesting article, i'm aploud you.

Annie said...

I learned a lot.. thank you for the info on a lazy Saturday morning.. it was interesting how you don't know for sure why hummingbirds like red..but you say.. insects likes red.. how do you know insects dont know red?

Wild Flora said...

Hi Annie,

Thanks for your comment. Information about insects' ability to see color comes from both behavioral experiments and from study of the photopigments in the eyes of different insect species.