In the twenty-first century, many birds are in trouble. Some of America’s most treasured grassland birds, including Bobolinks, Eastern and Western meadow-larks, and Northern Bobwhites, are showing steep declines. Of the 71 bird species unique to Hawaii during historic times, 26 have become extinct, and 30 of the remaining species are threatened or endangered. More than 75 percent of birds nesting in America’s aridlands, including sage-grouse, California Condors, and Elf Owls, are declining steeply or already listed as threatened or endangered.
Wetland bird populations are well below their historic levels, but many wetland species, from Bald Eagles and Osprey to American White Pelicans and Sandhill Cranes, are now thriving thanks to wetland restoration, which has become a model for bird conservation. Peregrine Falcons, extirpated from eastern North America by the 1970s, are now nesting in many areas after benefitting from the same protective measures that helped raptors in general, and also from reintroduction projects.
Strategic land management and conservation action are the tools we use to help species in peril. Our successes prove that when we set our minds to it, we can make the difference between life and death for populations and species.
Q Piping Plovers used to nest on the Lake Superior beach near my cabin. Last spring two showed up during migration, and the beach was closed for a while. But people ignored the signs and took their dogs on their regular walks, and the plovers moved on. What can we do to help these little birds?
A Many people have never heard of Piping Plovers, and so naturally some might feel resentful if told to walk their dogs somewhere else. One strategy that has allowed the closely related Snowy Plover to make a comeback on a Santa Barbara beach involves introducing people to this splendid bird.
Piping Plovers are specialists, with adaptations that make them perfectly suited for life on beaches and mudflats but virtually nowhere else. They feed on tiny water creatures washed to shore or in waterlogged sand along shallow rivers, large lakes, and oceans. They pick at visible bugs and bring small invertebrates to the surface by extending one foot slightly forward and vibrating it against the wet sand.
Piping Plovers are exceptionally hardy for being so diminutive. They nest in a scrape on open sand, gravel, or shell-covered substrate, or in dunes along shorelines. Their tiny chicks are exposed to high winds and blowing sand that would send most birds scurrying. The eggs and adult and chick plumage are perfectly camouflaged to protect them from Peregrine Falcons and other natural beach predators.
Though exquisitely adapted to this wild environment, Piping Plovers are not adapted to the changes that people bring. Where beaches haven’t been developed, all-terrain vehicles, running dogs, oil slicks, and other disturbances make it difficult for plovers to feed and nest. Gulls, raccoons, and crows that are initially attracted to a beach by picnickers and their garbage will also notice and eat plover eggs and chicks. Feral cat colonies imperil them in some areas.
At the public beach on the University of California-Santa Barbara’s Coal Oil Point Reserve, people wanted to protect the closely related and threatened Snowy Plover, which had stopped breeding along that beach. The U.S. Geological Survey (USGS), the Santa Barbara Audubon Society, and the University of California Natural Reserve System worked together to fashion a program that has brought the number of plover nests there annually from virtually zero from the 1970s through 2000 to a few dozen every year since 2004. How did they do this?
A USGS study determined the smallest part of the beach that could be closed to maximize protection of plovers with minimal inconvenience to beach users. In 2001, when a single Snowy Plover chick was seen near a dune-restoration project, the university installed a rope fence to enclose the core plover habitat along 400 yards of beach. The area stretched from wet sand to dry areas above the tidal zone but allowed people to walk at the water’s edge along the beach. Educational and regulatory signs were installed.
Perhaps the single most critical thing the partnership did was to empower an army of volunteer docents to become Snowy Plover ambassadors. I went to the beach to see them in action in 2005. I witnessed their interactions with passersby, showing and educating them about the plovers, requesting compliance with the dog leash law, requesting them to keep their distance from the fence, and scaring away crows. A spotting scope was trained on a plover chick, and I loved hearing people seeing them for the first time: “They’re so adorable!” “They look like marshmallows on stilts!” “How come I never heard of these birds before? They’re wonderful!”
Making people aware of the plovers and their plight in such a positive way has made protecting them much easier.
Q I own some forested property that I’ve been managing for income but also for the environment and to give something back to my local birds. I was going to plant some oaks but experienced foresters told me not to, because they’d never be big enough to bring in any income during my lifetime. What do you think?
A Planting trees is something we do for the future. Even young oaks can provide a lot of benefits for migrating Scarlet Tanagers and other birds, and for your viewing pleasure. My recommendation is to find out from your county extension office or state department of natural resources what the dominant forest type was in your area before settlement, and then choose a variety of locally native species to plant. Select a mixture that will allow you to selectively harvest some trees soon, for profit, while allowing other varieties to grow for the future benefit of birds and your descendents.
Q Our city recently passed an ordinance that allows people to replace lawn with native plants. Is this just a fad? Won’t it be bad for robins?
A Robins do love taking worms from lawns! But robins cannot live by worms alone — a large part of their diet comes from insects and fruits associated with other kinds of vegetation. Compared to turf lawns, natural plantings provide a much wider variety of animals, most notably butterflies and birds, with both food and shelter, while still fostering worms for robins to enjoy. And locally native plants are adapted to locally native conditions, requiring less watering, fertilizing, and pesticide applications than turf, allowing us to create a safer environment for people and birds.
Turf lawns are a necessary element in golf courses and playing fields, and will always appeal to some homeowners as well. But when local ordinances allow homeowners to replace traditional lawns with natural vegetation, they’re acknowledging the different aesthetic tastes of constituents. And allowing natural vegetation also acknowledges the different tastes of the avian community, from robins to hummingbirds.
THE CANARY IN THE COAL MINE: DEALING WITH PESTICIDES
Miners have long brought canaries into mines, knowing that the death of a canary was a warning of a clear and present danger to them, too. Wild birds have provided similar warnings to us from above ground. In the spring of 1955, George J. Wallace, professor of ornithology at Michigan State University, noticed that robins were dying around campus, and connected it to insecticides. By the summer of 1958, robins had been eliminated from campus and parts of the surrounding city.
Wallace’s work documented the devastating effect that DDT was having on songbirds. Meanwhile, Peregrine Falcons, Bald Eagles, and Osprey were declining dramatically, but weren’t dying outright. However, virtually no juvenile birds were being seen anymore. In 1968, Daniel Anderson and Joseph Hickey published a paper in Science documenting eggshell thinning in these birds, coinciding with the introduction of pesticides like DDT.
DDT killed insects on food crops and mosquitoes carrying malaria, so many argued that human beings should take precedence over birds. Although the deaths of songbirds and eggshell thinning in raptors did figure in Congress’s decision to ban DDT in 1972, another factor was the discovery of DDT and its byproducts in human mother’s milk.
The decision to ban DDT proved to have saved human lives. In 2002, scientists analyzing stored blood samples of pregnant women from the 1960s discovered that DDT levels in blood serum were highly correlated with low birth rates and premature births. Those “canaries in the coal mine” were giving us a sound warning. Meanwhile, in every place where DDT has been applied in the outdoor environment, mosquitoes were growing ever more resistant to it.
Although DDT is banned in the United States and other developed countries, in areas of the world where malaria is a problem, the World Health Organization today recommends the use of indoor spraying. DDT is taken up in the feet of mosquitoes, so when ceilings and bed netting are sprayed, they afford protection while minimizing effects on our own and natural food chains.
In Silent Spring, Rachel Carson wanted us to be mindful of the negative as well as positive effects of pesticides, to seek out alternatives when feasible, and when a pesticide seems to be the best solution to a serious problem, to use the smallest effective amount — a common sense approach for protecting humans and our crops as well as the natural environment.
Q A couple of times this year after my neighbor had her lawn sprayed, I found robins acting strangely, acting sick and even falling on their sides or on their backs. They ended up dying. My neighbor says that the pesticides she used are approved by the EPA and so are guaranteed not to hurt birds. Is that true?
A The EPA never “approves” pesticides; it registers them. And field-testing to prove a pesticide is safe for wildlife is no longer a requirement for registration; in order to be registered, a product must pass a complicated cost/benefit test; no tests on birds are required. Even a major bird-killing pesticide such as fenthion can remain on the market for many years, killing millions of birds, before its use is restricted or prohibited.
According to the U.S. Fish and Wildlife Service, about seven million birds are killed every year by common household lawn pesticides. In general, insecticides are more dangerous than herbicides, but both can cause neurological damage and cancers in birds and even people. It’s difficult and expensive to necropsy and do the necessary tests to learn if pesticides have killed a bird. Most modern pesticides break down very quickly, both in the environment and in the body, so finding the definitive cause of your robins would be difficult and expensive at best.
In addition to weed killers for destroying dandelions and insecticides for killing cutworms, some lawn care applications include fertilizers. Although fertilizers would not be to blame for sick robins, they seep down into groundwater, eventually working their way into lakes, rivers, and streams, where they contribute to the excessive growth of aquatic plants. So it’s very important to minimize the use of fertilizers as well as pesticides. Be sure to check the labels of every product you use, and if you hire a company to apply lawn products, make sure they tell you what products they’re using and the purpose of each one. In all cases, it’s sensible to apply the absolute minimum amount that would be effective for the problem a homeowner is tackling. Unless weeds are dire, it’s much wiser to pull or spot spray weeds than to spray every inch of lawn.
Better yet, an integrated pest management system can often maintain beautiful yards without formulated chemicals. The EPA has information at www.epa.gov/opp00001/factsheets/ipm. htm about using this “common-sense, effective, and environmentally sensitive approach to pest management” that will help you keep your family, pets, and wild birds safe. If your neighbors see your success with it, perhaps they’ll consider trying it, too.
Q When my nephew graduated from elementary school, I wanted to have a big balloon release but he said that would be bad for birds and, of all things, turtles! Is this true?
A Balloons are lovely floating in the sky, but eventually they come back to earth. Since two-thirds of our planet is covered by water, a great many released balloons find their way to lakes and oceans. Marine mammals, sea turtles, and many seabirds such as pelicans are killed or seriously injured when they encounter them and get entangled in the strings or swallow them. Strings from balloons sometimes ensnare birds in trees, too. You’re lucky to have such a conscientious and aware nephew! He may appreciate a tree planted in his honor that will provide food and shelter for the birds he treasures for years to come. (Of course, he’ll also appreciate a gift he can use right now, too!)
Q How are birds affected by climate change?
A Climate change is influencing the abundance, distribution, and timing of migration and breeding for many species. So far various climactic changes have helped some species, harmed others, and had little effect on the rest. A recent study by the National Audubon Society showed that more than half of the birds commonly found on the Christmas Bird Count are wintering farther north now than they did 40 years ago.
American Robins are now arriving approximately 14 days earlier than they did in 1981 on their breeding grounds in the Colorado Rocky Mountains. Tree Swallows have advanced their breeding date by up to 9 days earlier from 1959 to 1994. Red-winged Blackbirds, Eastern Bluebirds, and eastern populations of Song Sparrows now lay their eggs earlier because spring temperatures are warmer.
In addition to these effects on migration and breeding, birds are at risk from habitat changes caused by climate change, especially on the tundra, in alpine meadows, on sea ice and glaciers, in coastal wetlands, marine atolls, and oceans.
These species may face severe conservation challenges in the coming decades. Sea level rise may inundate islands, jeopardizing nesting birds. The potential spread of mosquito-borne avian malaria to highlands where the surviving Hawaiian honeycreepers have retreated is also a danger.
In the future, climate change is expected to affect the survival and reproduction of many bird species. Again, changes are expected to benefit some species and harm others. Changes in prey distribution and abundance, shrinking habitats, and changes in rainfall and water availability are expected to present great challenges to some birds on land and at sea.
Eastern Bluebirds occur across eastern North America and south as far as Nicaragua. Bluebirds living in the more northern and western parts of the range usually lay more eggs than do the more eastern and southern birds. Eastern Bluebirds typically have more than one successful brood per year. Young produced in early nests usually leave their parents during their first summer, but young from later nests frequently stay with their parents through the winter.
WEATHER: THE GOOD, THE BAD, AND THE UGLY
Only in cartoons do birds lounge atop rainbow colored clouds. In the real world, weather events may prove beneficial to some birds and harmful to others. Overall, birds are best adapted to the normal weather patterns of the areas where they have evolved, but birds use their wings to move about and are constantly developing new adaptations to new conditions.
Sudden Storms
For some birds, the more rain, the better. The nesting success of Song Sparrows is directly related to precipitation levels, but cool, rainy springs coincide with lower nesting success for Tree and Cliff swallows.
Storm systems are, and have always been, dangerous for many birds. In the early 1800s, John James Audubon watched as two nighthawks were struck and killed by lightning. In 1941, a lightning bolt blasted four Double-crested Cormorants from a flock. All four died, though their feathers weren’t scorched. That same year, more than 50 Snow Geese were struck by a single lightning bolt. Necropsies revealed that one was badly burned, but most had died from the impact as they hit the ground.
Many trees felled by lightning have been found to contain dead woodpeckers, owls, or other birds. In 1953, two hailstorms in Alberta killed 150,000 ducks and geese. In 1960, thousands of Sandhill cranes were killed by hail in New Mexico. In 1931, a bluebird pelted by hail in Iowa suffered two broken wings. In 1938, hail killed two California Condors that had been eating a horse carcass. In May 2004, a hail storm killed more than 100 nesting Great Blue Herons in northern Wisconsin. Yet even in the face of that devastating storm, at least 50 herons were unharmed.
Hurricanes can kill birds outright. They can also devastate the vegetation along huge swaths of shoreline. And because so many houses, garages, industrial plants, gas stations, sewage facilities, and other human structures can get flooded, toxins and debris can be released into floodwaters, degrading coastal wetlands even more.
Devastating Droughts
Droughts and floods have always played a part in the natural world. Although severe ones can devastate local populations of birds, on a wider scale they’ve been balanced out by favorable conditions elsewhere. If climate change alters rainfall patterns so some areas become consistently drier or moister, this will change the composition of vegetation and insect life of those areas, increasing bird populations of species that associate with increasing plants or insects and decreasing bird populations of those that don’t.
Droughts can have unexpected impacts on birds. For example, when water levels drop, feeding swans often pick up grit at the bottom of shallow waters that are normally too deep for them to reach. Most North American lakes have large amounts of lead shot sitting at the bottom like tiny time bombs. Efforts to phase out lead shot began in the 1970s, but a nationwide U.S. ban on lead shot for all waterfowl hunting was not implemented until 1991. Canada instituted a complete ban on the use of lead shot in 1999, after banning its use near bodies of water and on national wildlife areas earlier. Even though lead shot is no longer raining down on lakes, rivers, and streams, the lead shot already there continues to sit until a swan, loon, or other bird picks it up as grit. The lead is ground up in the gizzard, dissolves into the bloodstream, and usually leads to the bird’s death.
Rising Temperatures
Within certain ranges, insects are more active as temperatures rise, so birds depending on them may benefit from a warming trend. Considering how many birds are found in tropical areas compared to temperate ones (tiny Costa Rica, about the size of West Virginia, has more bird species than all of North America north of Mexico!), it’s possible that in the long run, in some places, birds may benefit from rising temperatures.
But harmful insects would also grow more active. In Hawaii, where native birds were decimated by malaria after mosquitoes were introduced, most remaining populations of several endangered species now exist only at elevations too cool for mosquitoes. As temperatures rise, mosquitoes and the diseases they carry will move higher in the mountains, shrinking and even eliminating remaining habitat for these vulnerable birds.
Rising water temperatures also encourage eutrophication, marked by excessive aquatic plant growth. While the plants are actively growing, they produce oxygen, but as they die, even as other plants are growing, decomposition of dead plants absorbs oxygen and releases carbon dioxide. Mosquito larvae can thrive in oxygen-depleted water because they take in their oxygen at the surface through a breathing tube.
Mayfly nymphs feed on mosquito and other larvae in their aquatic stage, and provide enormous quantities of food for migrating and nesting birds when they emerge as flying insects in their adult stage. But mayflies require highly oxygenated water. When eutrophication makes lakes and ponds inhospitable for them, we lose a natural control over mosquito numbers and an important supply of food for such beloved and already-declining birds as Purple Martins and Common Nighthawks.
As warmer temperatures arrive earlier in spring, a mismatch between timing of nesting and availability of food seems to be arising. For example, many plants and insects are emerging earlier. Migratory songbirds that spend the winter in the southern and central states may take advantage of warm temperatures and earlier food availability to migrate and breed earlier. Meanwhile, birds wintering in the tropics have no way of knowing what the weather is like across the Gulf of Mexico, and arrive closer to their normal arrival date, sometimes missing important surges in insect numbers that fuel their migration and provide a good abundance of food for breeding.
Finally, the northern range limits of some opportunistic birds are related to temperature. When there is less ice in winter, Mallards and Canada Geese winter farther north, and their winter range may expand. More and more starlings, robins, and other abundant species may survive in higher numbers in northern winters, in some cases crowding out birds that are more adapted to harsh conditions; as those populations retreat further north, their potential total range will shrink. Melting permafrost is expected to affect lemmings, the primary food for Snowy Owls. Many species of birds are physiologically stressed by extreme heat, too; increasingly hot summers may take a heavy toll on these species.
Q I keep hearing about birds in decline, but I’m seeing more robins than ever. What’s the truth?
A You’re right that robins are increasing. These generalists have adapted very well to the habitat changes that come with urbanization, and they are thriving. But some birds are dangerously declining. In 2007, the National Audubon Society released a report that showed many of our most common and beloved birds have declined by 50 percent or more since 1967. For example, Eastern Meadowlarks have declined by 72 percent.
The population density and range of Greater Sage-Grouse have shrunk since Lewis and Clark documented them on their expedition. Common Nighthawks and Whip-poor-wills grow increasingly scarce. The Red Knot declined by fully 80 percent between 1995 and 2005, so in 2005, environmental organizations petitioned the U.S. Fish and Wildlife Service (USFWS) to list the rufa subspecies as Endangered and to designate critical habitat for them, but their petition was denied. It grows increasingly difficult to “list” declining species to give them the protection that official designation as a Threatened or Endangered species affords.
Despite the declines of some of these species, there is plenty of room for hope. Habitat restoration has helped Kirtland’s Warbler populations increase more than ten-fold in just three decades. Where wetlands are restored, waterfowl populations respond quickly. The Conservation Reserve Program, conservation easements, and other initiatives have helped declining grassland species, too. When we set our collective will to solving a problem, we usually succeed.
Q When I was on a local bird walk in Florida, I saw some beautiful birds that the leader identified as Eurasian Collared-Doves. I was thrilled, but she said that they’re not native to America and so are not a “good” species! Is that true?
A Eurasian Collared-Doves are beautiful birds and have an important place in the ecosystems of southeastern Europe and Japan, where they are native, but they are not native to Florida. These doves were released in the Bahamas by humans in the 1970s and had spread to Florida by 1982. They are still most abundant near the Gulf Coast but have spread as far as California, British Columbia, the Great Lakes region, and Veracruz in Mexico.
So far, Eurasian Collared-Doves in America don’t seem to be competing with native species for food or nesting sites, and this introduction may well prove to be less destructive than most. But some introduced species are implicated in the declines of native birds because they compete for nesting sites. European Starlings and House Sparrows aggressively take over nesting cavities of native birds such as Red-headed Woodpeckers, Purple Martins, and bluebirds.
Q Don’t introduced birds contribute to an area’s biodiversity? And isn’t that a good thing?
A Biodiversity is the variation of life forms within and among ecosystems and is often used as a measure of the health of a biological system. So it certainly does appear that by adding a new species, we’re adding to biodiversity.
Sadly, it’s not as simple as that. Consider invasive plants: when one — such as kudzu, purple loosestrife, Eurasian water milfoil, or cheatgrass — colonizes an area, it quickly crowds out a variety of native plants, greatly reducing the overall plant biodiversity of that area. That, in turn, reduces the biodiversity of animals. For example, when cheatgrass invades rangeland in the West, it crowds out native sage grass, and so is one of the primary causes of the dramatic decline of Greater Sage-Grouse.
Invasive nonnative birds can do the same thing. House Sparrows, like native bluebirds, wrens, Purple Martins, and Prothonotary Warblers, nest in cavities that they cannot excavate themselves. All of these species normally take over an abandoned woodpecker hole, a cavity formed when a branch rots out, a nest box, or similar enclosed space. These cavities are, for many species, a limiting factor. When House Sparrows colonize an area, they aggressively evict native species from these nest sites, often destroying eggs and killing chicks and adults. Widespread colonization of House Sparrows is one of the factors that contributed to the decline of Purple Martins.
It’s hard to predict which species will become invasive in a new place, and even harder to control an invasive species once it’s released. Preventing introductions in the first place is vital for preserving biodiversity.
Q Robins and Cedar Waxwings are always visiting my buckthorn trees. My mother-in-law says buckthorn is an “invasive exotic” and that I should get rid of it. How can it be bad if the birds love it?
A Common or purging buckthorn is indeed an invasive exotic in America. It was introduced here partly as a garden shrub and partly because of its purgative properties in herbal medicine. It’s an invasive pest, crowding out other shrubs and serving as a primary host of the soybean aphid.
Birds do gorge on the berries, and then fly off to poop out the seeds in other places. This seems like a good deal for the birds, but buckthorn may not be very good for them and is definitely not good for the environment. Because buckthorn crowds out native shrubs, it reduces the amount of food available to birds in times of the year when it isn’t fruiting.
So, yes, if common buckthorn is growing in your yard, it’s a good idea to cut it down. It grows back quickly, so many authorities recommend that after you cut it down you treat the stump with an herbicide. If you do this, be careful to limit the application to only the buckthorn. Replace buckthorn with fruiting trees and shrubs native to your area. You can find out good varieties to choose from local conservation and gardening clubs or your state department of natural resources or environmental conservation.
Many birds that eat a lot of fruit have digestive tracts capable of separating out the seeds and regurgitating them, but the Cedar Waxwing lets the seeds pass right through. Scientists have used this trait to estimate how quickly waxwings can digest fruits.
Invasive species can pose dangers that aren’t appreciated until it’s too late. For example, the introduction of mosquitoes onto the Hawaiian Islands posed a serious problem for native humans and birds, but that problem was gravely exacerbated when nonnative birds were introduced. These birds from other areas carried blood-borne pathogens that they had long ago evolved immunities against. When mosquitoes bit them and then bit a native Hawaiian human or bird, they transferred these pathogens to them.
Malaria in particular decimated both the native human and bird populations of the Islands. Most native Hawaiian birds have been extirpated at the lower elevations of the islands where mosquitoes occur. One of the concerns about climate change on Hawaii is that warmer temperatures allow mosquitoes to spread to higher elevations, reducing the areas where native birds can still survive.
Many of the introduced birds on the Hawaiian Islands are stunningly beautiful, but in every case, they live in other places as well. Native Hawaiian birds, such as the Iiwi and Apapane, are found nowhere else on the planet. Of the 71 known endemic Hawaiian birds, 26 are extinct, and 30 of the remaining species and subspecies are listed as endangered or threatened by the U.S. Fish and Wildlife Service.
Q I know about the Dodo and the Passenger Pigeon, but what other birds have gone extinct in the past century?
A The last captive Carolina Parakeet died in a zoo in 1918. Eskimo Curlews may be extinct — coordinated efforts since the mid-1980s to locate these elegant shorebirds have failed, but isolated unconfirmed sightings even in the 2000s continue to surface so there is hope that a few still exist.
Many researchers believed Ivory-billed Woodpeckers had become extinct until 2004, when documented (but controversial) sightings were made of at least one male in the Big Woods of Arkansas. Intensive efforts to locate this species in Florida, Arkansas, and elsewhere have proven difficult, and no unequivocal proof that the species still exists has emerged.
Bachman’s Warbler from the southeastern United States is most likely extinct. The last confirmed sightings in the United States were all near Charleston, South Carolina, in 1958–61, but scattered unconfirmed sightings in the Southeast and in Cuba continued into the 1980s.
Most American extinctions have taken place on Hawaii, where just during the twentieth century we lost the Laysan Rail, Hawaii Oo, Kauai Oo, Oahu, Olomao (probably), Lanai Hookbill, Greater Amakihi, Nukupuu (probably), Lesser Akialoa, Greater Akialoa, Kakawahie, Oahu Alauahio, Ula-ai-hawane, Black Mamo, and the Poo-uli, which was just declared extinct in 2004.
HELPING ENDANGERED SPECIES MAKE A COMEBACK
When severely declining birds are listed as Threatened or Endangered, the Endangered Species Act is extremely effective at helping them. Bird conservation initiatives that were started when the Endangered Species Act was enacted and enforced have had some genuine successes. Peregrine Falcons, for example, had been extirpated from virtually the entire eastern half of North America, but reintroductions, often using the chicks of captive falcons from falconers, brought the species back so that its status has been upgraded from Endangered to Threatened.
Bringing Back Raptors
After DDT was banned, Osprey and Bald Eagles made remarkable comebacks without reintroductions. During the 1960s, Bald Eagle numbers remained fairly high in Alaska and much of Canada but declined to 417 breeding pairs in the Lower 48 by 1963. By 1999, their numbers there had increased to more than 5,000 pairs. They have been removed from the Endangered species list except in the Southwest region where they are designated Threatened.
Between the 1950s and the 1970s, nesting Osprey declined by 90 percent on the coast between New York City and Boston. Their recovery has been startling — their 2001 population was estimated to reach 16,000 to 19,000 pairs.
In 1975, surveys found fewer than 200 singing Kirtland’s Warblers, limited to a small area in Michigan. The 2007 surveys found 1,707, including 8 in Wisconsin and 2 in Ontario.
Kirtland’s Warblers are extraordinary specialists, nesting only on the ground beneath the bottom branches of jack pine trees. Jack pine is fire-adapted. Its cones remain tightly closed, often for many years, until exposed to the intense heat of fire, when the seeds are released and germinate on the burnt ground. As jack pine trees age, they lose their bottom branches, making them unsuitable for Kirtland’s Warblers to nest. Once the jack pines in an area have lost their lower branches, that area will be abandoned by the warblers until fire starts the cycle over again.
Kirtland’s Warblers were never abundant, but declined dangerously in the midtwentieth century until they numbered fewer than 200 pairs by the 1970s. Two factors caused their decline. Fire suppression prevented new jack pines from replacing old ones, and Brown-headed Cowbird populations mushroomed locally. By the late 1960s, in one sample of 29 nests, 70 percent were parasitized and only two fledgling warblers were produced.
Thanks to controlled burning and cowbird trapping, Kirtland’s Warblers are currently estimated at over 3,000 individuals.
The Wonderful Whooper
Whooping Cranes, which had dwindled to 15 or 16 individuals in 1941, numbered 328 in the wild (including natural and introduced populations) as of April 2009. Protection of the wintering habitat at Aransas National Wildlife Refuge and intensive efforts at reintroduction are responsible for these increases.
Despite this success, Whooping Cranes are still extremely vulnerable. The natural population that winters in the estuary along the Texas Gulf Coast depends on rich supplies of blue crabs for their winter diet. When crab supplies are abundant, the birds have excellent winter survival and put on plenty of weight. During those years, they arrive on their spring breeding grounds in top condition, and their breeding success in the north is high.
But blue crab numbers decline as the estuary’s salinity increases. More Whooping Cranes die during these winters, sometimes from emaciation, sometimes in collisions with power lines and other structures as they fly greater distances in search of food. The winter of 2008–09 was such a year; as of the end of April, they had lost 23 birds, more than an 8 percent loss.
The salinity of the marsh is weather-related; when rainfall declines, water levels go down in the Aransas River and other waterways emptying into the estuary. But these water levels are also related to human consumption of water, not just for drinking and agricultural irrigation but also for swimming pools and lawns. As the human population of Texas continues to grow, the future of the Whooping Crane remains in question. Fortunately, a great many people and organizations remain focused and committed to protecting this beautiful and charismatic species.
Bringing Puffins Back
In 1885, hunters took the last Atlantic Puffins from Eastern Egg Rock in Maine’s Muscongus Bay. By the midtwentieth century, puffins remained on only two islands in American waters, Machias Seal Island and Matinicus Rock, both off the coast of Maine.
Although puffins continued to do well on more northern islands, they didn’t recolonize their historic nesting islands despite protection. Puffins tend to return to the islands where they were hatched, and once an island has no surviving birds, there are no birds to return to it.
In 1973, Dr. Stephen Kress started an experimental project, sponsored by the National Audubon Society, to return Atlantic Puffins to Eastern Egg Rock by raising young birds in burrows on the island. Between 1973 and 1986, 954 young puffins were transplanted from Newfoundland to Eastern Egg Rock. The young puffins were reared in artificial sod burrows for about one month. Audubon biologists placed handfuls of vitamin-fortified fish in their burrows each day, in effect taking the place of parent puffins, and 914 of these successfully fledged, flying to the ocean to spend the next few years. It takes a minimum of two to three years for young puffins to return to their islands to breed, and some of these puffins began returning to Eastern Egg Rock in June of 1977.
In 1984, National Audubon and the Canadian Wildlife Service began a similar puffin restoration project at Seal Island National Wildlife Refuge in outer Penobscot Bay. In 2008, thanks to Project Puffin, 101 puffin pairs were found nesting at Eastern Egg Rock and 375 pairs were counted at Seal Island NWR. The numbers are considered minimums, as Maine puffins nest in hidden burrows under boulders and are hard to count.
The restoration of Atlantic Puffins to U.S. coastal islands is a wonderful case study in how commitment and innovative action can bring a lost population back.