Recycling for the Birds

What's garbage to humans can be home to the birds

• Cynthia Berger
• Apr 01, 1994

Cornell university student Charles Dardia had a problem. He was spending the summer of 1992 studying common terns at New York's Oneida Lake, and part of his job was to mark the nests-or, rather, the rocky hollows that passed for nests-with red surveyors' flags so they would be easy to find again. Trouble was, someone kept stealing the flags. He would leave the nests neatly marked and come back the next morning to find nary a flag in sight.

The culprit? Double-crested cormorants-big, black, diving birds-which were methodically gathering up the flags and putting them in their own nests.

Ornithological literature is full of stories of birds making nests out of stuff stolen from humans. Massachusetts ornithologist and early conservation activist Edward Howe Forbush reported that in 1913 cormorants off the coast of Labrador built their nests entirely from materials scavenged from a sunken trading ship, including men's pipes, ladies' combs, pocketknives and hairpins. In his Encyclopedia of North American Birds, John Terres describes a canyon wren's nest in Fresno County, California, built entirely of office supplies, including paper clips, rubber bands, thumbtacks and paper fasteners. In Nest Building and Bird Behavior, researchers Nicholas and Elsie Collias report a pigeon nest, located near a Michigan factory, that was built of pieces of iron wire. They also tell of a house martin nest in Great Britain constructed not with the usual mud, but with wet cement filched from a construction site.

This is not just a biological peculiarity, it's also good news. You can turn this avian fondness for human junk to the birds' advantage--and yours. For pure fun and a great close-up view of fascinating bird behavior, convert your castoffs'into nesting materials for your backyard birds.

This is truly a higher form of recycling: Keep waste out of the landfills and help the birds. As in any well-run recycling program, curbside pickup is available; just leave the materials in an open area on your patio or lawn.

Vivian Pitzrick has a host of tips on recycling for the birds. If anyone knows nests, it's Pitzrick. She's an amateur birder from central New York who has turned her hobby into a contribution to science. Each spring Pitzrick searches woods and fields for nests-noting how many eggs were laid, how many hatched, and so on-then contributes the information to the Cornell Laboratory of Ornithology's Nest Record Card Program. She has become Cornell's chief nest finder and a true bird expert.

According to Pitzrick, you can attract different birds with different nesting materials. "Cedar waxwings especially like short strips of rags," she says. "Eastern kingbirds, too. I carry rags with me in the field when I'm searching for nests. It helps me to see if waxwings are around. I put the rags out in open places, and they fly in to pick them up."

Pitzrick suggests a host of household items that birds will incorporate into their nests, including bits of cotton (at last, a use for aspirin-bottle wadding), short lengths of string (thrifty Pitzrick saves the twine from bags of potatoes), yarn (unravel an old sweater), upholstery stuffing, raveled rope, excelsior, thread and even dental floss. "Orioles love frayed binder twine, and yellow warblers in particular like cotton," she says. The birds probably like cotton because it resembles milkweed fluff, which they often use to line nests.

Robins and vireos like yarn, and catbirds and thrashers seem to like small squares of fabric-Pitzrick cuts material into 2-inch squares or into half-inch wide strips no more than 6 inches long. "Not too long," she emphasizes. "The birds could get tangled up." Northern orioles typically use the long fibers from milkweed plants in their nests, but will readily substitute string, yarn and cloth. (Terres recorded the amount of string that one northern oriole took from his backyard during nesting season: 75 feet.)

Pitzrick also supplies mud for barn swallows, which use it to cement their nests to the rafters in her barn. Other birds that incorporate mud into their nests include American robins, cliff swallows, wood thrushes, Eastern phoebes and purple martins. Pitzrick says, "The soil should be stone-free; the birds are a little choosy." High-clay soils are best-they make sticky mud. A pothole in Pitzrick's driveway is a perfect mud dispenser: "I carry mud and put it in this hole," she says. "It doesn't bother my husband, it's just a little hole." Lacking a pothole and a tolerant husband, offer mud in a shallow pan, such as a cake pan.

Craig Tufts, manager of the National Wildlife Federation's Backyard Habitat Program, cultivates a mud pit in his yard, too. "Mud also attracts butterflies," he says. So parents can now think of childish excavations to China not as blots on their lawns, but as multiple-use conservation areas.

Tufts says his family has transformed spring cleaning from a day of drudgery into a day for bird conservation. "Anything the birds can use, we set aside for them," he says. "Bits of string, dryer lint, old rags-even vacuum cleaner dust has lots of good stuff in it."

Opportunities abound. After a visit to the barbershop, Tufts takes hair clippings home. Hair is a favorite of many nesting birds, including chipping sparrows, vermilion flycatchers, loggerhead shrikes, pine warblers and pine siskins. If you're too shy to ask your stylist for leftover locks, says Tufts, you could collect castoffs from your dog or cat. Or just sit quietly in your yard: Nuthatches and chickadees are notorious for collectinghair before it's been shed, boldly plucking away at sleeping pets and even pet owners.

Tree swallows and violet-green swallows are two species you can attract with feathers. National Audubon Society researcher Steve Kress, author of The Audubon Guide to Attracting Birds, turns an old feather pillow into a bird resource. "We toss the feathers in the air or drop them from a second story window, and the tree swallows come out of nowhere," he says.

Nesting tree swallows are known for their feather fights. They battle in full flight like tiny Sopwith Camels, stealing feather booty from one another's beaks. Feathering the nest is a serious goal, says Cornell University ornithologist David Winkler. His research has shown that young birds raised in nests well-insulated with feathers grow faster-and are ready to leave the nest sooner-than young raised in nests from which he removes the feather blanket. Presumably, baby birds in feathered nests don't have to use as many calories to stay warm, so more of their energy goes into growth.

If you don't have a pillow or an old down vest you can feather pillage for, try a craft shop, or make friends with someone who raises chickens. Just don't pick up road-killed birds, warns Tufts. Even dead, most bird species are protected by various state or federal laws.

Nest-watchers say swallows seem to prefer white feathers, and many birds that use string or yarn also seem to prefer white to other colors. These observations led Jerome Jackson, a biology professor at Mississippi State University, to launch a homegrown research program on color preferences.

Jackson routinely puts aside nesting materials for his backyard birds. ("I have this canvas sack," he says. "Anything that's good for the birds-in it goes.") He persuaded his kids to hand over their Easter baskets ("It's for science, kids!"), full of colorful cellophane grass, for a test: Which color would. birds like the best? So far, the birds seem to use all colors. One oriole built its entire nest of the crinkly stuff.

Jackson stresses that artificial nesting materials should be biodegradable. "Don't give the birds anything that won't break down, like nylon or polyester rags," he says. Cellophane Easter grass biodegrades, but the plastic kind doesn't. Monofilament fishing line and fiberglass insulation don't biograde, either.

Are you ready to start recycling for the birds? You should put materials out early in spring, when the first robin arrives-even if snow still covers the ground. You can continue to offer nesting materials as late as August, because some birds nest two or three times over the course of the summer.

Birds defend their nesting territories, so place your offerings in more than one location. If cats prowl the area, don't leave materials on the ground. Drape them on shrubs, over a clothesline or in the crotch of a tree. A good way to dispense yarn or string is to put it in a plastic mesh bag, the kind onions and oranges come in. Poke a few holes in the mesh, so birds can easily pull things out, and hang the bag on a tree. Leave a few strands of string or yarn sticking out; fluttering pieces will attract the birds' attention. If you want to use something more durable than an onion bag, wire suet baskets can double as nest-material dispensers. Or use a platform-style bird feeder to dispense twigs and other inflexible stuff.

With all this recycling, don't overlook ways to provide birds with natural sources of nesting materials. Tufts says simple changes in your landscaping will make your yard a haven for nesting birds. "Let your yard go a little wild," he says. "Offer a variety of shrubs and trees of different heights. Minimize the amount of space devoted to turf grass and emphasize vegetative variety. Just about any plant that provides food and shelter for birds will make good nesting material."

Landscaping for nesting birds actually translates into less yard work, not more, says Tufts. "Don't be a superclean gardener," he urges. "Leave some twigs under the shrubs. Leave some leaves on the ground to decay. The leaf petioles [stems] break down last, and they make great nesting material." Many birds incorporate twigs into their nests, Jackson says, including thrashers, mourning doves, house wrens, purple martins andcatbirds. Some birds like prickles and thorns. Mockingbirds will fly a long way for the twigs of Julian barberry bushes. Other good thorny or twiggy shrubs include viburnums, deciduous holly, spirea and dogwood.

Tufts has turned a corner of his lawn over to wildflowers. "Regular grass clippings are too short-birds like long grass stems," he says. He also grows wild grapes "for their shreddy bark" and encourages moss in shady spots-it's a favorite of chickadees and titmice.

Some birds nest in hollow trees. To attract these species, you can erect nesting boxes, which are really just artificial tree cavities, or you can start a real tree cavity by drilling a hole below a crotch. Before doing this, check one of the many how-to books about bird housing for instructions on how to make cavities without damaging trees. Another approach is to leave a dead tree standing and let nature take its course. Some die-hard enthusiasts have even transplanted dead snags into their backyards.

A final tip: Stop using pesticides-they kill the insects that birds eat. And learn to value spiders--they're an important food for birds, and their silk is a great nesting material. Some small flycatchers and all of the hummingbird species use spider silk to construct nests.

One last precaution before you start making your house a drawing card for avian architects. Considering what's turned up in some nests, better bolt the lawn chairs to the patio.

Cynthia Berger is managing editor of Living Bird magazine at Cornell University's Laboratory of Ornithology. Check out National Wildlife Federation's Backyard Habitat Program for more information on how certify your backyard.