Selasporus platycercus
Description
The Broad-tailed Hummingbird belongs to the taxonomic family Trochilidae – the hummingbirds – of which there are some 340 species, all in the Americas. Male Broad-tailed Hummingbirds are easily distinguished from females by the iridescent red gorget (throat) feathers that develop during the first year of life. Females lack the gorget, their breast feathers are a characteristic grey, and their throat may exhibit some red spotting.
Distribution and Habitat
Broad-tailed Hummingbirds prefer meadows with abundant wildflowers flanked by forests. Broad-tailed Hummingbirds are migratory and fly to summer breeding grounds in the western Rocky Mountains in the spring then return to Mexico and Guatemala to winter. Their breeding range stretches from central California to as far east as eastern Kansas and from southern Idaho to southwest Texas.
Adaptations
These tiny birds weigh only about 3.5 grams, or a bit over one tenth of an ounce. They are well adapted to their feeding habits with hovering wings, long thin beaks, and grooved tongues that allow them to harvest the nectar of flowers and catch tiny insects. Broad-tailed Hummingbirds emit a loud “trill” with their wings to attract mates and defend their territories. The ability to enter torpor to survive frigid mountain nights is also an amazing evolutionary adaptation of these and other hummingbirds. In a torpid state, the birds lower their metabolic rate and drop their body temperature dramatically until it is close to the ambient (surrounding) temperature. Without this trait the birds would risk starving to death as they try to maintain physiological homeostasis, including an elevated body temperature.
Ecological Relationships
Hummingbirds benefit some flowering plants by providing pollination services and those plants reward the hummingbirds with nectar. Hummingbirds can also reduce insect populations on the flowering plants they visit. Adult hummingbirds have few predators, but nests, eggs, and nesting birds are food for raptors and other birds, snakes, and foraging carnivorous mammals.
Status and Conservation
Broad-tailed Hummingbirds are protected under the Migratory Bird Treaty Act. However, Broad-tailed Hummingbirds are not recognized as endangered and are typically listed as a species of least concern regarding conservation.
Highlighted RMBL Research
In the 1980s and 1990s, several RMBL researchers trained male Broad-tailed (and Rufous) Hummingbirds to visit hand-held Ipomopsis aggregata flowers in a temporary aviary in Gothic. The flowers in all of these experiments could be manipulated by painting to alter flower color, changing flower shape, etc. Below we see Dr. Mary Price in 1988 with the experimental subjects. For details, see Campbell et al. 1991.
Encyclopedia of Life
Learn more about Selasporus platycercus at the Encyclopedia of Life.
References
Calder, William A. and Lorene L. Calder. 1992. Broad-tailed Hummingbird (Selasphorus platycercus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/016
Attribution
Many thanks to Cody Butero and Dr. Pat Magee at Western State College for this submission, and to RMBL researcher Dr. Nickolas Waser, Emeritus Professor of the University of California at Riverside, for his review and additions.
Glossary
homeostasis – The condition of any system in which its internal properties are maintained within narrow limits. When referring to living organisms, the internal properties are physiological ones such as rate of metabolism, pH of the blood, body temperature, and the like.
torpor – A state of short-term hibernation in which an animal reduces its rate of metabolism and hence its body temperature, thus conserving energy.
