By Derek Stoner, Family Programs Coordinator
A young female Rufous Hummingbird sips from a nectar feeder in Avondale, PA. October 2009 photo by Kathy Weaver.
The 30-degree weather this past weekend did not faze the young female Rufous Hummingbird visiting a backyard in Avondale, PA. Weighing in at 3 grams and possessing a stove-hot metabolism with a heart beat of 600 beats per minute, this tiny bird is thriving on the nectar of late-blooming flowers, tiny insects and spiders, and a generous suppply of sugar water offered by the owners of a vibrant backyard habitat.
A young male Rufous Hummingbird perches on a feeder in Dover, DE. Notice the spider silk caught in his beak, as spiders are a key dietary component of hummingbirds in winter. January 22, 2009 photo by Derek Stoner.
How do they survive the cold? These hummingbirds have the unique ability to “turn down the thermostat” so to speak, through a process called torpor. As the hummingbird settles in for the night to sleep, their heartbeat slows to less than 100 beats per minute. The torpid state has been described as “suspended animation” as the bird enters a zone of semi-consciousness.
A Rufous Hummingbird perches on branch on January 22, 2009. This bird survived overnight temperatures of 5 degrees! Photo by Derek Stoner.
The obvious question is: what is this hummingbird doing here right now? Is he lost? Is he going to survive the cold winter? Fortunately, scientists(bird banders in particular) in recent years have started to unravel this story of how hummingbirds are spending the winter on the East Coast. There are several bird banders in the region who are working to solve this mystery. Well-known author and bird bander Scott Weidensaul’s website has an excellent discussion of this research: http://www.scottweidensaul.com/research_hummingbirds.html
A Rufous Hummingbird stretches his wings. December 1, 2006 photo by Jim White.
The Rufous Hummingbird is the most widely-distributed hummingbird in North America, breeding as far north as Alaska. The Rufous has been recorded in every US state except Hawaii, and undertakes the longest migration of any North American hummingbird. The majority of Rufous Hummingbirds spend the winter in Mexico and Central America, but new evidence points to the fact that more of these birds are wintering in the eastern United States than we may realize.
A Rufous Hummingbird visiting Jim White's feeder in Winter 2006. Notice the silver band on the bird's leg! Photo by Jim White.
Other species of hummingbird are also being documented wintering along the East Coast, from Calliope to Allen’s to Broad-billed Hummingbirds. Scientists and birders alike are re-thinking their ideas about hummingbird migration and the selection of wintering habitat.
There is a lot more to learn about these amazing hummingbirds. Stay tuned for part two of this story!