health & environment: Safe Passages: Making Michigan safer for migratory birds
To keep birds safe as they pass through the state, Project Safe Passages Great Lakes encourages the owners of tall buildings to follow some simple recommendations during the peak migratory seasons. SPGL Days are from March 15-31 and Aug. 15 - Oct. 31. The proclamation asks all Michigan residents to turn off nonessential lighting between 11p.m. and dawn and participate in SPGL Days by “reduc[ing] the use of unneeded electricity throughout the state.” Owners and occupants of buildings over four stories tall are encouraged to:
Turn off all lights between 11p.m. and 6 a.m. on unoccupied floors and in unused spaces.
Keep light “inside” by covering windows or using task lights instead of ceiling lights.
Turn off all exterior illumination from midnight to dawn.
Michigan lies in the path of two principal migration routes—the Atlantic and the Mississippi Flyways, and each spring and fall hundreds of thousands of birds perish while crossing our state. Dr. Daniel Klem Jr., an ornithologist at Muhlenberg College, estimates that in the United States more than one billion birds, roughly 5 to 20 percent of the yearly bird population are killed in bird-building collisions every year. More than half of these collisions are fatal, and birds that at first seem to have survived the impact often become easy targets for predators. The danger is perhaps greatest during fall migration, when inexperienced birds are making the trip for the first time.
Birds have excellent vision, so why don't they simply avoid windows? Day-flying birds likely observe the natural features of the surrounding landscape—trees, the sky, other birds in flight—mirrored in the glass. They see a safe flyway rather than an obstacle.
Likewise, nocturnal species and night-flying migratory birds often collide with structures that project above the treeline into airspace that they expect to be empty. Additionally, birds migrating under the cover of darkness can become transfixed by lighted high-rises. Instead of alerting them to the danger, the gleaming towers lure them closer. They become disoriented and fly into the hazard and one another. The danger is especially acute for flocks of migrating songbirds because, in stormy weather, they fly at lower altitudes where the skies are teeming with artificial lights.
In addition to following the recommendations of SPGL, there are simple steps that homeowners and businesses can take to reduce the number of bird-building collisions. The usual strategy is to break up reflections, making slick buildings and glass visible to birds. This can be accomplished inexpensively by affixing strips of translucent tape onto windows at 10 inch intervals or by drawing similarly spaced lines with a yellow highlighter.
Stained glass also works well, while decals and silhouettes of predatory birds are less effective since they only cover small areas. Adding exterior screens or netting to windows are the best solutions; they not only break up reflections, but also prevent fatalities by softening the blow.
Technological innovations promise bird-safe glass in the future. One new technology, “fritted glass” containing ceramic grains that are visible to birds, is being tested at Swarthmore College, and it seems to be working. Up close, the windows are clearly etched with closely spaced rows of small circles, but from a slight distance the design almost disappears. Another type of glass is embedded with a UV pattern that birds can see, but is almost invisible to humans.
Participating in Project Safe Passages Great Lakes is one way to make Michigan safer, but there are plenty of other ways to help. We generally think about migration as a biannual event, but migratory birds must remain constantly on the move in order to survive. Here are 10 additional ways you can help make the passage safer for Michigan’s migratory birds:
1. Create habitat by letting your yard go
Habitat destruction is the primary threat to migratory bird populations in Michigan. Just one percent of the original forests in the eastern United States and only 10 percent of marshlands and one percent of prairies in the midwest remain. Fall is traditionally the time to tidy up the yard before it snows by removing leaves and brush, mowing the lawn, pulling up the remnants of the summer garden, or manicuring trees.
You don’t necessarily have to let the yard go wild, but at least wait until spring to collect brush, pare down trees, or pull out your tomato vines. Just piling some leaves beneath the trees or letting part of the lawn go to seed can make your yard a valuable pit stop for migrating birds.
2. Add native fruit or berry trees to your landscaping
Consider planting native fruit trees or shrubs with berries on your property. These are nature’s perfect bird feeders, providing food and shelter for birds year round. Native plants are also perfectly suited to survive local environmental conditions; they don’t require pesticides (another significant threat to birds) or other special treatment. Wild Ones and The Michigan Native Plant Producers Association can help determine the best plants for your yard.
3. Create a snag in your yard
Dead trees often provide more habitat for birds than living trees. If you have a sizable tree in your yard that you plan to remove, consider trimming it to create a snag or wildlife tree instead. Birds use snags and living trees with snag-like features (like hollow trunks) for nests, nurseries, food caching, shelter, and perching. An arborist can assist you with developing your snag in a safe manner.
4. Keep birdhouses and nestboxes up
By November, most insectivorous migrants have left Michigan for warmer climates, but seed-eaters may winter in your yard. Even birds that are acclimated to frigid temperatures will freeze to death without adequate shelter. Instead of putting away birdhouses and nest boxes, clean them thoroughly with a dilute bleach or vinegar solution. When dry, return them to the yard stocked with insulating grasses. On bitter nights small, cavity-nesting birds like bluebirds, nuthatches and titmice may all snuggle together inside.
5. Add a heated birdbath to your yard
During winter, dehydration can be a problem for birds. Thirsty birds sometimes resort to eating snow, wasting precious energy. Placing a heated bird bath in your yard provides birds with a reliable source of fresh water when it is scarce. What’s more, a bird bath may help you attract more birds to your yard. Some types of birds do not visit feeders, but they will use a bird bath. Solar and electric models are available online and at specialty retailers.
6. Buy jingle bells for the cats in your neighborhood
To protect birds, ideally, all cats should be indoor cats. A bell will not keep cats from killing birds.
Outdoor cats (both feral and domestic) are a significant threat to migratory birds. According to The American Bird Conservancy, felines kill more than 500 million birds annually in the United States. Naive fledglings are exceptionally easy pickings. Fresh from the nest, they are unwary of threats and cannot fly well. An Australian study found that urban cats wearing bells only caught and killed 50 percent fewer birds, so bells should only be used as a last resort.
If your neighbor’s cat continues to wander into your yard and they refuse to keep the cat inside, offer a collar with a bell. It can be difficult to determine who, if anyone, owns roaming cats, but feral cats are responsible for half of the carnage. Outfitting them with bells may be better than doing nothing.
7. Buy shade-grown coffee
Not only are migratory birds at risk from habitat destruction on their breeding grounds in North America, but loss of habitat at critical stopover sites along migratory flyways and on their wintering grounds are growing concerns. One way to protect birds while they are abroad is by purchasing shade-grown coffee. Tropical forests are being cleared to make way for monoculture at an alarming rate.
Shade grown coffee farms produce coffee in the understory of an intact rainforest, providing habitat for a rich diversity of species, especially migratory birds. A Mexican study found close to 200 species of birds on shade coffee farms, while sun-coffee farms had less than 10.
8. Leave a legacy for birds
Locally and globally, habitat conservation is the number one way to help birds. According to the National Audubon Society, since the 1970s a quarter of all species of birds in the United States have declined in population, primarily due to habitat loss. An enduring and meaningful way to impact the future of birds is by making a legacy gift for the preservation of wildlife habitat. Many types of planned gifts are possible, including bequests, charitable annuities, trusts or securities, and gifts of family land or real estate.
The Planned Giving Roundtable of Southeast Michigan offers assistance with planning your legacy, including advice on structuring your gifts to allow lifetime use of your property or investment income. If your estate is modest, consider requesting charitable donations to your favorite preservation organization in lieu of flowers when you pass on.
9. Reduce your carbon footprint
Habitat loss and degradation are currently the greatest threats to migratory birds, but meteorological shifts are an impending problem. Each species of bird is best adapted to survive the environmental conditions that are typical of the places where they live. Climatologists like the University of Michigan's Dr. Henry Pollack argue that average temperatures in Michigan have increased markedly in the past 15 years, meaning hotter, stormier summers may become the norm.
This has sobering implications for Michigan's birds, particularly fledglings. Young birds lacking adult plumage have poor thermoregulatory capabilities. In suboptimal weather—like the prolonged heatwave Ann Arbor experienced this summer-many birds succumb to heat stress and dehydration.
Hotter weather can also mean less food is available during critical stages of development. The success of many migrants depends on having young in the nest when high-protein food resources, like caterpillars and grubs, are most abundant. The adaptive success of transcontinental migratory birds is founded upon this perfect synchronization between the timing of the insect's life-cycles and the period when young birds are learning to feed themselves.
Higher temperatures also increase the prevalence of insect-born diseases, like West Nile virus, and impact the food supply. In warmer weather mosquitos not only reach the biting stage more rapidly, but diseases spread as birds congregate at fewer watering holes.
10. Save the date for the Christmas Bird Count
Monitoring the distributions of our migratory bird species helps conservationists make informed decisions. The Washtenaw Audubon Society invites birders of any skill level to participate in The Christmas Bird Count, the longest running ornithological database. Data generated from the count comes entirely from volunteers. Experienced bird watchers may enjoy the camaraderie of other birders while conducting the field census, but anyone with a bird feeder in the census zone is invited to take part.
In spite of their perilous existence, migratory birds are the ultimate survivors. Our modern birds descended from a survivor of the Cretaceous-Tertiary extinction, which wiped out the dinosaurs. The transoceanic, cross-continental migration of most North American birds is an extraordinarily successful survival strategy — as long as their passages remain safe. Protecting animals whose journeys span global boundaries takes intercontinental cooperation.
Michigan’s pioneering efforts to save the endangered kirtland's warbler — a migratory species that nests only in small patch of northern-central Michigan and spends nine months in the Bahamas--have proven that cross country approaches to habitat conservation are feasible. Perhaps, one day bird-safe glass will be mandatory for new skyscrapers in the same way that turtle exclusion devices — escape hatches for sea turtles that are trapped in trawling nets — are required for commercial fishing operations.
For more information on protecting Michigan’s migratory birds and their habitats visit the following websites:
And don't forget to turn out the lights!
Mary Mathias is a Media Outreach Coordinator for NPR’s “Issues of the Environment” program on WEMU 89.1 and reports on environmental topics for AnnArbor.com She can be reached at firstname.lastname@example.org.