Marjorie saw the first flash of red, a female fluttering in a tree at the edge of the garden. A few days later we saw the bright red male pecking at sunflower seeds in the frozen snow. I hung a feeder close to the woods, filled it with seed, and waited, watched. Finally we saw the male again, perched on the feeder, and later that day two females together on the snow.

Northern cardinals are not rare birds in Maine these days and have not been for several decades. You can find reports from the early 1900s of Pennsylvania as the northern limit of their range, but now they are common in southern and central Maine, occasionally sighted in northern sections of the state.

They are rare in Marjorie’s garden, nonexistent until this winter. I suspect they were attracted by the free lunch and, if they are thinking ahead, by the woods at the garden’s edge, a perfect nesting sight. We hope to hear their song in early spring, “what-cheer, what-cheer … wheet, wheet, wheet, wheet,” notes that will bring back boyhood memories of watching backyard birds in Georgia.

With the arrival of these three birds, the biodiversity of the garden has increased by one species. If they nest in the adjoining woods, what might be their impact on the ecology of the garden?

I have always thought of cardinals as strictly seed eaters and was surprised to learn that their diet is composed of about 30 percent insects as adults and nearly 100 percent insects as nestlings; together, beetles and caterpillars account for nearly half of the nestling diet. This means that a family of cardinals nesting near the garden should make a significant dent in the insect pest population as they raise their young.

In researching the diet of northern cardinals, I discovered an Internet collection (http://birdsbybent.com/) of Arthur Cleveland Bent’s bird species biographies, originally published between 1919 and 1968 in the 21-volume series, “Life Histories of North American Birds.” Writing on the natural history of the northern cardinal, Bent cited the work of bird biologist W.L. McAtee (1908), written in a time when farmers complained of crop losses to birds:

“The cardinal has been accused of pilfering certain grains, notably corn, to an injurious extent. But in view of the fact that only 8.73 percent of the total food is grain, and that more than half of that amount is waste, the loss is greatly overbalanced by the destruction of weed seeds alone, which compose more than half of the vegetable food. Moreover, some of the weeds consumed are especially destructive to grain crops.

“The following list of important pests the bird has been shown to prey upon is in itself sufficient proof of the cardinal’s value. The list includes the Rocky Mountain locust, 17-year cicada, potato beetle, cotton worm, bollworm, cotton cutworm, cotton-boll weevil, codling moth, rose-beetle, cucumber-beetle, figeater, zebra caterpillar, plum scale, and other scale insects.”

Now, extrapolate this information to today’s garden. Northern cardinals that grace our garden with their beauty in winter may also help control weeds and insect pests during the growing season. What better reason could there be to avoid using pesticides, to simply enjoy watching these beautiful birds as they go about their lives?

Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to rmanley@ptc-me.net. Include name, address and telephone number.