There are many myths about feeding wild birds. Some are silly. Others are deadly (for the birds). A sidebar to the Backyard Gardener column {Home, May 2} added unfounded credence to one of the silly myths about hummingbird feeding -- that red food coloring is harmful to the birds.

Experts at the U.S. Fish and Wildlife Service and the FDA say there is nothing in the scientific literature to support the statement that "red dyes build up in the kidneys (or livers) of hummingbirds," or that commercial hummingbird food (with artificial coloring and preservatives) is dangerous or preferred less than plain sugar water by the tiny birds.

Manufacturers put red dye in hummingbird food for two reasons: Hummingbirds have learned to associate food with the color, and the red coloring helps you keep track of how much nectar is in the feeder.

Here are some dangerous myths about feeding hummingbirds:

Keep your feeders full. Wash them when they look dirty (once a week, month, or season).

In fact, hummingbird feeders must be washed with hot soapy water at least twice a week. Sugar water ferments in summer heat. Hummers eat more than their body weight in sugar water each day. That's enough fermented "nectar" to kill them.

When ants and bees are a problem at the feeder, deter them by adding an ant moat filled with axle grease, turpentine or vegetable oil.

The truth is that ant moats filled with anything but water can spill and contaminate the feeder. Axle grease, turpentine and rancid vegetable oil can kill hummingbirds.

It's safe to spray your roses and vegetables with pesticides as long as you don't do it near the feeder.

Even careful use of pesticides may harm birds if they eat still-living contaminated insects, or if the pesticide wipes out the nesting bird's insect protein supply.

-- Heidi Hughes

The writer is the author of "Backyard Bird Feeding," published by the U.S. Fish and Wildlife Service.