The sugar-coated (but incomplete) view of hummingbirds and flowers is they co-evolved for mutual benefit, but Booted Racket-tails are also “nectar thieves.”
By Rex Graham
They feed on many tubular flowers designed to exclude bees and butterflies in favor of hummingbirds. The flowers provide high-energy nectar in exchange for pollination. These flowers co-evolved with the Booted Racket-tail, which is one of many birds pictured on Ecuador’s postage stamps.
However, Booted Racket-tails have a not-so-sweet side. They are secondary nectar thieves of several flowering plants, including some in the heather (or heath) family. Two hummingbirds with longer bills, Collared Incas and Green-fronted Lancebills, quickly withdraw nectar from the flower tubes. They pollinate the flowers as they feed early in the day.
Booted Racket-tail ‘robbing’
However, on the afternoon shift, the shorter-billed cheaters buzz in, according to the research of noted Spanish ornithologist Luis Navarro.
Blue-tailed Emeralds are “primary robbers,” says Navarro. They pierce the base of tubular flowers, damaging reproductive-tissue and causing nectar to leak. It’s pilfering, not pollination.
Booted Racket-tails arrive next. They are “secondary nectar robbers” in alliance with the Emeralds. Both hummingbirds pilfer without providing pollination.
The ultimate effect of nectar robbing isn’t understood. Many flowers robbed this way boost their nectar production. Navarro and his colleagues are trying to understand the full consequences.
The deeply forked tail of the Booted Racket-tail is another story. Birders love the males’ pair of bare-shafted, plume-tipped feathers. (A species with a similar tail is the stunning Marvelous Spatuletail.) The Booted Racket-tail is a “puffleg” hummingbird: the males look over-dressed with dense white feathers around their legs.
Female racket-tails are responsible for the males’ extreme feathers. Long ago, longer tail feathers may have given males a survival advantage that females wanted for their chicks. Now, exaggeration of the feathers goes hand-in-hand with enhanced female choice. The ladies get what they want.
Biologists call this phenomenon “truth in advertising.” You can see it at work in the outsized antlers of male Elk. For a female hummer or Elk, exaggerated size of a single feature indicates other desirable traits (nutritional condition, social status, and resistance to predators and pathogens) that she wants for her offspring.
I believe that the more we watch, photograph, protect and study Booted racket-tails, the better for the species, all birds, all wildlife and all humans.