Beautiful Native Plants


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Wednesday, February 8, 2017

Winter Food for Birds

Field of Canada goldenrod. © Beatriz Moisset
 When the days get shorter and other signs of winter hang in the air, most birds pack their bags and leave for warmer climates. They are not necessarily running away from the cold weather, but from the lack of their favorite food, insects.

Not all leave; the ones that can make it through the winter on nuts and berries stay. Also those who know where to find insects stay. Woodpeckers belong to this latter category. Some, such as hawks and owls, who feed on other birds, mice and other small creatures, also stay.

The seed eaters, the most common winter birds, may not be strict vegetarians. They know how to locate some animal protein here and there and welcome these nutritional supplements when given a chance. It takes skill, sharp eyes, and perseverance because this kind of food is scarce and well hidden through the colder months. The winter landscape is devoid of flying insects or succulent caterpillars chomping on leaves. Whatever insect life there is, it is snuggled up under bark or soil. Or, if it is in plain view, it is hidden by color and shape, blending with the surroundings and holding perfectly still in the shape of eggs or cocoons.

Aphid and eggs on rose stem

Late December. ©Beatriz Moisset

At the end of the summer season, aphids produce eggs, minuscule ovals, glued to leaves or stems, so insignificant that we may fail to notice their presence. Sometimes chickadees are seen working their way up and down a rosebush stem nibbling at invisible tidbits. They feast on this snack, adding some protein to their drab winter diet.

Goldenrods supply an interesting insect food to winter birds. Some goldenrods present a peculiar round thickening about an inch in diameter half way along the stem called a goldenrod round gall. Some patches of goldenrods have numerous galls of this kind. They are easier to spot during the winter, when all the leaves are gone and the stems remain standing.

Goldenrod round gall produced by the goldenrod gall fly
©Beatriz Moisset
 How is a gall made? A fly lays an egg inside a goldenrod stem in the spring. Along with the egg, it injects some remarkable chemicals in the spot. The chemicals cause the stem to swell into a round tumor which becomes home and pantry for the growing larva. The maggot-like future fly sits in the heart of the growing gall feeding on the nutritious tissues and protected from enemies. By the end of summer it is fully grown, but it will not be ready to come out of this secure place until spring, so it sleeps through the winter curled up at the very center of its mansion.

Two birds seek these snacks in times of scarcity, downy woodpeckers and chickadees. They face a difficult task to get to their treasure. The gall has become as hard as wood. Cutting one open with a utility knife or a small saw is no easy task. Believe me, I have done it. I have also found and collected galls broken in by birds.

The woodpecker has a beak like a chisel. With surgical precision it cuts a clean hole. The chickadee’s tool, on the other hand, is not so efficient. So this bird has to labor hard, wrecking almost the entire gall to reach the center. It is easy to tell who the eater was by their distinctive signatures.

Goldenrod galls opened by birds

Downy woodpecker, left. Chickadee, right
© Beatriz Moisset
Wanting to learn more about birds in winter and their insect food, I went on a frustrating Google quest. I tried words such as “bird,” “food,” “winter,” “insect,” and “diet”. No matter what combination I used the overwhelming majority of hits referred to bird feeders and feeding. Even when I subtracted “bird feeder” and “feeding” from the search I failed to find studies on natural winter insect food. Doesn’t anybody study birds’ winter diet?

Finally I found a delightful exception by one of my favorite nature writers, Bernd Heinrich. A rigorous scientist and first class writer, his books for the general public are enjoyable as well as packed with solid information. I had read his Winter World: The Ingenuity of Animal Survival years ago and was happy to delve into it once again.

Chapter nine, The Kinglet’s Winter Fuel, tells us about the golden crowned kinglet and its means of survival in the harsh Maine winters. This delicate tiny bird feeds almost exclusively on insects. How does it manage at a time in which insects seem unavailable? Heinrich’s endless curiosity led him to answer this question after seeing these thumb-sized feathered wonders nibbling at apparently non-existing food near the tips of spruce trees. He caught a few and found their gizzards packed full of inchworm caterpillars. Determined to know more, he whacked a number of trees and gathered everything that dropped from them onto a white sheet spread on the snow.

He collected caterpillars along with a few other things. Eventually he managed to raise some of the inchworms and found out the moth they turn into at the end of winter. All this research took him several winters and the assistance of a number of his students; but he finally knew that kinglets depend on the “variant” moth for their winter survival.

I love the chapter’s closing line: “To care for the welfare of kinglets, it is necessary to care for moths.” Notice that he talks about moths, not bird feeders.

I often wonder about the proliferation of bird feeders and bird food in this country. I recognize their educational value and their importance in suburban and urban places where bird’s habitats are all but gone. But, I also wonder about the land devoted to growing bird seed. Perhaps, pesticides and methods to keep birds away are in use. Isn’t that another way of taking habitat away from wildlife? When we supply them with suet, do they neglect their insect-eating task? In short: Do we feed birds for their benefit or ours?
Woodpeckers at bird feeder
© Beatriz Moisset
In addition to bird feeders, we should remember that other ways to help birds include taking care of the moths, and berries and nuts, and, yes, dried up goldenrod plants and their round galls. In the long run, this may be the best way to feed birds.


© 2013, Beatriz Moisset. First published in Native Plants and Wildlife Gardens, 2013