There are more than 300 species of hummingbirds existing in the world today, all in the Western Hemisphere. Most live in the equatorial rain forests of Columbia and Ecuador. Only 15 species breed in the United States, and only one – the ruby-throated-breeds east of the Mississippi. How lucky we are to have these jeweled treasures visit us each spring and summer.

A popular, but false old folk tale stated that hummingbirds migrated to their wintering grounds by hitching rides on the backs of geese. All hummingbirds migrate under their own power; our ruby-throat migrates from Central America to southern Canada and the Eastern United States each spring, and retraces its route in the fall. If this seems incredible, consider that its route takes it across the Gulf of Mexico – a non-stop flight of more than 500 miles. It accomplishes this feat by adding 40 to 50 percent of fat to its body weight just before its journey.

Daily food requirements are no slight matter, either. Hummingbirds have an extremely high metabolism and need to consume between 6,000 and 12,000 calories per day to stay alive; their resting heart rate is almost 500 beats per minute.

A wide range of information regarding hummingbirds and their feeding exists. Many feeders come with their own set of instructions, which, when compared to advice given by knowledgeable birders and ornithologists, is erroneous. It is important, then, to go to the right source when considering putting out feeders.

I’ve found a fact sheet produced by the University of Maine Cooperative Extension to be helpful. It details the bird’s life history and gives instructions on gardening for hummingbirds – all in a condensed, easily accessible format. It also compiles critical advice on feeder care and maintenance, such as:

. Changing the solution every one to two days, and sooner in very hot weather; artificial nectar ferments quickly. Fermented nectar causes liver enlargement in hummingbirds; the attendant mold and bacteria is also harmful to them.

. Cleaning and sanitizing the feeders when the solution is changed. This means scrubbing all feeder parts with a very small amount of dish detergent, rinsing with cool water, immersing it in a 10 percent bleach solution for at least three minutes, rinsing well again (soap or bleach residue will harm hummingbirds), and letting it air dry before adding fresh nectar.

In addition, the standard measurement when making up a batch of sugar-water is four parts water to one part sugar. Bring the solution to a boil, and then remove from heat and let cool. Never use honey, as this may produce fungal infections in hummers; and never use artificial sweeteners. The sugar-water ratio mentioned above is recommended because it comes closest to mimicking the nectar content of flowers, but it is no substitute for the real thing. The fact sheet provides a list of favorite hummingbird plants, when they bloom, and what conditions they grow best in.

Commercial nectar mixes are more expensive than a carton of sugar, and often contain potentially harmful additives like food coloring. It is not known what effect this has on a hummer’s physiology. The red base or body of the feeder is enough to attract them – I have never used red food coloring in my sugar water, and the hummers still flock to my feeders.

To order the “Understanding Ruby-throated Hummingbirds and Enhancing Their Habitat in Maine,” fact sheet, contact your county extension office or visit the Web at: www.umext.maine.edu/publications/homegarden.htm.

Chris Corio, a volunteer at Fields Pond Nature Center in Holden, can be reached at fieldspond@juno.com