Backyard feeding: Birds with a sweet beak
Sweet treats give migrating songbirds an energy boost when they need it most
Published: March 1, 2005
|In recent years, books promoting diets low in carbohydrates have soared to the top of best-seller lists. Fortunately, birds are functionally illiterate, so they haven’t jumped on the bandwagon. Hawks and owls, of course, are on a fairly strict “Atkins diet” without even knowing it, as are many flycatchers, at least during the breeding season. But most songbirds sneak in at least a few carbohydrates here and there, and some, such as the Eastern Kingbird, switch to a very high-carb frugivorous diet while they are on their tropical wintering grounds. |
Birds need high-energy foods to sustain high-energy activities and their rapid metabolic rate. When food is plentiful, they lay on extra body fat that they can readily burn off during times of scarcity or when they require extra calories during migration, egg production and incubation, and molting. Fruits and berries are also high in vitamins.
Not just for hummingbirds
Just as human marathoners often chow down on high-carb spaghetti dinners the night before their 26.2-mile race, many spring migrants gorge on meals high in carbs, both in the natural world and at our feeders, before major migration events. Tanagers and most warblers, for example, fly all the way from Central and South America to North America, and some travel as far as northern Canada and Alaska, an exhausting journey that can last a month or more from start to finish. Individual birds cover hundreds of miles on nights when weather conditions are favorable and bide their time, laying on more fat and resting up, when conditions for long flights are less promising.
Each spring many Ruby-throated Hummingbirds fly directly over the Gulf of Mexico from the Yucatan Peninsula to the Louisiana or Texas coast, a minimum of 500 miles non-stop, without any possibility of finding rest or food until they arrive. Before the tiny birds take off, they lay on extra body fat by gobbling up insects and spiders, and load up their stomach and crop with carbs to get off to an energetic start. Once the hummingbirds arrive in the United States, they migrate by day, feeding along the way, proceeding as the earliest flowers open up. Hormones impel the migrants forward days or weeks before the vast majority of nectar-bearing flowers will open, but the birds have discovered an excellent back-up source of carbs — Yellow-bellied Sapsucker drill holes.
Fruits That Birds Will Flock To
These fruits are sure to attract birds to a platform feeder, basket, or holder in your yard this spring.
• Frozen or fresh strawberries, blueberries, raspberries, cherries
• Banana pieces
• Raisins, currants, dates
• Melon chunks or slices
• Chopped grapes, apples, pears
• Halved oranges
• Drained, halved coconut
|Ruby-throats arrive in the northern reaches of their range about 10-14 days after sapsuckers arrive in theirs, and the hummingbirds apparently time their migration to take advantage of this excellent source of carbohydrates. Even after migration, northerly hummingbirds tend to place their nests near sapsucker wells and often follow sapsuckers in their daily movements. A great many other birds, including kinglets, warblers, and phoebes, are also attracted to sapsucker wells. In northern Minnesota, where I live, I invariably discover my first Ruby-crowned Kinglets and Yellow-rumped Warblers of the year in the same branches in my aspen tree where my first Yellow-bellied Sapsucker has been working.|
We think of sugar water as an ideal food for hummingbirds and orioles, but other birds also enjoy it, including woodpeckers and even warblers. During Minnesota’s exceptionally cold, rainy May in 2004, one male Cape May Warbler learned to fly up from a nearby branch, hover at my perchless hummingbird feeder for three or four seconds, and then return to the branch to take a breath. He’d repeat the action seven or eight times before flying off. The Cape May is the only warbler with a tubular tongue adapted to sipping nectar, so it is the one most likely to appear at fruit and nectar feeders. Hummingbird feeders with perches large enough to accommodate orioles are also likely to attract other species occasionally, especially Downy Woodpeckers.
Jelly and marmalade are popular with many backyard birds. For some reason, orioles continue feeding on the treats even after they’ve abandoned oranges for the season, and catbirds are especially fond of grape jelly. But it’s important never to set out too much at once. Last spring, a dozen orioles, five tanagers, two catbirds, and at least 20 Cape May Warblers were visiting my feeders. On a day when I was going to be away all morning, I put a full cup of grape jelly into one bowl, figuring that was about the amount the birds would go through in that time. I came home to discover a Red-breasted Nuthatch totally mired in the jelly, his body almost completely immersed, only his eyes and beak still above the surface.
Grape Juice Warbler
The Cape May Warbler has well earned its reputation for being a sweet tooth. In addition to visiting the occasional hummingbird feeder, the bird has been observed sipping from wells drilled by sapsuckers, eating the nectar-rich catkins of peach-leaved willows, and, on its tropical wintering grounds, defending the massive yellow flower heads of century plants. What’s more, reports dating back to the early years of the last century reveal a decided fondness for grape juice.
W. F. McAtee published one of the first accounts. He observed Cape May and Tennessee Warblers piercing grapes in Bloomington, Indiana, during the autumn of 1903. The warblers were constantly busy catching insects, McAtee wrote. “Frequently, however, they dashed into the vines and thrust their bills quickly into a grape. Sometimes they withdrew them quickly; again they poked around in the interior of the grape a little, and always after these attacks, they lifted their heads as in drinking. This action suggested a reason for piercing the grapes, that I am satisfied is the true one, that is, the obtaining of liquid refreshment.”
Reports of juice-swilling Cape May Warblers came from central West Virginia as well. “Their method was to puncture the skin of the berry at one point, extract a little juice, and move on to the next,” wrote Maurice Brooks in the Auk in 1933. “They would systematically work over every berry in the cluster, if undisturbed, and they soon became exceedingly tame. It is no exaggeration to say that there were hundreds of the birds in the locality.”
Ornithologist and specimen collector Frank L. Burns observed similar behavior in a Pennsylvania vineyard in September and October of 1913. The sugary juice and abundant insect prey appeared to provide ample fuel for the Cape Mays’ autumn migration. “Specimens secured early in this remarkable flight carried no fat, in fact were rather lean,” Burns wrote, “but after some days of feeding became fat, inactive and even sluggish; an adult female shot in the act of eating from a grape, and brought to me for identification by a neighbor, was positively enveloped in fat.”
You can read the reports cited above in their entirety here:
Brooks, M. 1933. Cape May Warblers destructive to grapes. Auk 50(2): 222-223.
Burns, F. L. 1915. The Cape May Warbler (Dendroica tigrina) as an abundant autumnal migrant and as a destructive grape juice consumer at Berwyn, Pa. Auk 32(2): 231-233.
McAtee, W. F. 1904. Warblers and grapes. Auk 21(4): 489-491.
The perils of preserves
Had I not come home when I did, he almost certainly would have succumbed to hypothermia. Fortunately, the nuthatch happened to be accustomed to my voice and to feeding out of my hand, so he didn’t panic when I fished him out and bathed and dried him. Also luckily, I’ve been trained and licensed to rehabilitate wild birds, so I knew what to do: I held him under a gentle stream of warm water, rinsing him and carefully rubbing away the jelly. I didn’t use any detergents, which are invaluable in cutting through grease and oil but also wash away natural body oils that are critical in waterproofing feathers. After bathing, I blotted off the water with soft paper towels, then let him nibble at his feathers to dry and realign them.
“Jelly Belly” needed three complete baths over almost four hours. Between each cleaning he patiently sat on my finger, preening and eating mealworms. After I released him, he didn’t return again all day, but the next morning there he was, good as new. Just a hint of purple remained on his belly feathers to remind me of his ordeal and the importance of offering jelly only in small amounts.
Other early-spring sources of carbohydrates include the old fruits and berries still clinging to shrubs and trees from last year. Robins, waxwings, and orioles are drawn to these, and when we offer similar sweet treats at our feeders, a surprising number of species may visit, including some we seldom think of as “feeder birds.” Orioles, attracted by the color orange, quickly notice halved oranges, and other birds, noticing the orioles, sometimes check out the feeder as well. When I add thawed frozen strawberries, blueberries, or raspberries, and chopped grapes or apples, robins, catbirds, tanagers, and even warblers quickly appear and devour them. In appropriate habitat, bluebirds also visit feeders for fruits.
The old maxim “You are what you eat” could be said of waxwings, whose nature is as sweet as their diet. Waxwings seldom if ever appear at feeders, but in spring we often find them dining on last year’s crab apples and the first apple blossoms. And waxwings’ convivial nature would certainly be called “sweet” in a human. The birds defend no territories against their own kind and often pass berries and flower petals from one bird to another, sharing the treats with their entire flock. I used to be mystified by this behavior until I was rehabilitating a Bohemian Waxwing one winter. At the time, hundreds of waxwings were feeding on mountain ash berries in my yard, so I brought in a handful of the fruits for the bird I was caring for. It eagerly ate five or six, but after 15 minutes or so, the berries came out the other end, completely undigested. Before I fed more berries to the bird, I rolled them between my thumb and fingers for a while, softening their waxy coatings. These were digested. Apparently, waxwings’ charming habit of sharing food not only helps seal social bonds but also aids the birds’ digestion.
In contrast, other birds on such sweet diets are astoundingly pugnacious. On several occasions, I’ve seen Cape May Warblers chase Yellow-bellied Sapsuckers from the hapless woodpeckers’ own drill holes, despite the fact that at 50 grams (1.8 ounces), a sapsucker weighs nearly five times as much as a Cape May Warbler (11 grams, 0.39 ounces). Of course, I’ve also seen Ruby-throated Hummingbirds chase off sapsuckers, and hummingbirds average a mere three grams (slightly more than a tenth of an ounce) — the sapsuckers outweigh them by a factor of 16!
Anyone who has watched hummingbirds battling for supremacy at a feeder knows better than to call the handsome little birds “sweet,” despite their sugary diets. But whether it’s sweets to the sweet or sweets to the pugnacious and feisty, high-carb diets provide energy and nutrition to some of our favorite birds, sweetening our lives in the bargain.
Laura Erickson is the author of Sharing the Wonder of Birds with Kids, which won the 1997 National Outdoor Book Award. She writes a monthly column about birds for the Minneapolis Star Tribune and a bimonthly column called “For the Birds” for Country Today, and she writes and produces the public radio program “For the Birds.” ||