A Little Bit More
Hummingbirds have the highest metabolism of all warm-blooded animals, with the possible exception of mammalian shrews. Their energy consumption is so high that at times - on long, cold nights, for instance – they even go into a state of torpor to stretch out their energy reserves so they won’t starve to death.
Although not all North America’s hummingbirds travel as far as the Ruby-throat, they also require extra “fuel” reserves to make their migration flights possible. Ruby-throats add more than 50% to their weight in preparation for their flight and then begin their long migration, not from the coast, as you might expect, but from well inland in Florida or Georgia, ending their trip well inside Mexico.
Hummingbirds have been timed in wind tunnels at a maximum speed of 43 kph (27 mph), and although their speed across the Gulf is unknown, even a speed in excess of 43 kph would require more than 20 hours of non-stop flying! On the return trip north, Ruby-throats arrive in the southern U.S. by March or early April. By mid-May, the northern-most populations have arrived in Canada.
Hummingbirds “drink” nectar, a good source of carbohydrates, but they eat a fair number of invertebrates too. The insects and spiders they catch as they visit flowers provide protein, an important part of their diet. But, like marathon runners, they spend their last days before migration “carbo-loading” – stocking up on the carbohydrates that offer quick fuel for a long trip.
Definitions
Topor: a state of inactivity, extremely sluggish function
Activities
Hummers Galore
Objectives: Identify ranges of hummingbirds in North America
Materials: Field guide to birds that includes all of North America, globe of world may help
There are 18 species of hummingbirds known to breed in North America, north of Mexico. Take a look at the following 7 species (these are more common) to see where in North America they breed.
- Costa’s Hummingbird
- Black-chinned Hummingbird
- Ruby-throated Hummingbird
- Calliope Hummingbird
- Broad-tailed Hummingbird
- Allen’s Hummingbird
- Rufous Hummingbird
This is an opportunity for students to examine their field guide to find answers to the following questions. Range maps can be rather “generalized” in their coverage so don’t become too exact when determining exactly where a bird breeds. Students will need to look at and compare the ranges of all 7 hummingbirds listed to answer the following questions.
Use a field guide to birds of eastern and western North America to answer the following questions about hummingbirds. You may want to use a globe so you can look at longitude to help you answer some of these.
- Which hummingbird species breeds the farthest north in summer?
- Which hummingbird species has the largest breeding range?
- Of these seven hummingbird species, how many can be found in Canada?
- Of these seven hummingbird species, how many can be found in Alaska?
- Are there any states or provinces that have NO breeding hummingbirds (include Hawaii)?
- Which hummingbird has the easternmost breeding range?
- Which hummingbird has the westernmost breeding range?
- If we assume that as hummingbirds evolved, they spread out geographically into new territories farther and farther from their original home range, in what general area of the New World do you think the very first hummingbirds lived? (Look at the map included with the activity to find your answer.)
Generalized map of breeding ranges of hummingbirds.
Key Concepts
Behavior and Regulation, Identification, Populations and Ecosystems
Questions
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