Now although the number and variety of birds that migrate has decreased over the last two decades, several foreign species continue to visit National Zoological Park during winters. Previously, almost 5,000 migratory birds spread across more than 10 species used to fly down to the Delhi Zoological Park. But now this number has fallen to an alarming 500-odd birds belonging to hardly five-six species. According to the Zoo’s curator several true migratory birds like Siberian crane, Brahminy duck, Mallard, Red-Crested Pochard and White Stork have not visited the Delhi zoo over the last few years. This decline is due to a number of reasons including atmospheric pollution, hunting by humans, lack of food, global warming etc.
Local migratory birds also turn up at the Delhi Zoo, and this place becomes a treat to watch for bird lovers. October end and November are the months when the birds start arriving, and more birds are estimated to come by January and February.
STATE WHAT WE KNOW ABOUT THE CHANGING STATE OF BIRDS:
Since the year 1500, we have lost over 150 bird species – an extinction rate far higher than the natural background. Today, one in eight bird species is threatened with global extinction, with 189 species Critically Endangered, and Red List assessments show that things are getting worse. Particularly alarming are sharp declines in many formerly common and widespread species. This is a signal of wider environmental problems, and of the erosion of biodiversity as a whole.
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Why birds are declining:irds are declining:
Humans are responsible for the threats to birds. Expanding and intensifying agriculture and forestry destroy and degrade habitats. Inadequately managed fisheries, ever-spreading infrastructure, invasive alien species, pollution and overexploitation all pose serious problems. Climate change, with impacts already visible, may be the most serious threat of all. These threats have deeper causes, rooted in our failure to accord wild nature its true value.
Sound environment:
Over the past few decades, the world’s governments have endorsed many international agreements relevant to the conservation of biodiversity, demonstrating their willingness to cooperate in tackling important environmental issues. The challenge now is to harness this commitment and ensure that concrete actions are taken where they are most needed. In several countries, the engagement of civil society and indigenous peoples’ organisations has resulted in impressive progress. There are signs of increasing action in the private sector, too.
Agriculture and forestry are the key drivers of habitat destruction of birds:
In Africa, habitat clearance for agriculture and logging threatens 50% and 23% of Important Birds Areas (IBAs) respectively. In Europe, agricultural expansion and intensification are among the most serious threats affecting IBAs.
Proportion of IBAs impacted by different classes of threats in Africa and Europe
Analysis of data held in BirdLife’s World Bird Database (2004)
In Africa, habitat clearance for agriculture threatens over 50% of Important Bird Areas (IBAs), with degradation owing to shifting agriculture an additional pressure (Fishpool and Evans 2001). In Europe too, agricultural expansion and intensification are among the most serious threats affecting IBAs, with a high impact at 35% (Heath and Evans 2000). In Africa, selective logging or tree-cutting affects 23% of IBAs, with degradation owing to firewood collection (including charcoal production) and forest grazing being additional, often related pressures (these threats are of less importance in Europe where little old-growth forest remains). In Africa, ongoing or planned infrastructure development (including dam and road building) is a further key cause of habitat destruction, with 21% of IBAs affected. In Europe this is also a major factor affecting IBAs, with a high impact at 37% .
The Effects of Oil on Wildlife:
We have all seen pictures and videos of wildlife covered in black, sticky oil after an oil spill. These pictures are usually of oiled birds. Many people are not aware that it is not just birds that get oiled during a spill. Other marine life such as marine mammals can also suffer from the effects of an oil spill. Even small spills can severely affect marine wildlife.
Not all oils are the same. There are many different types of oil and this means that each oil spill is different depending on the type of oil spilt. Each oil spill will have a different impact on wildlife and the surrounding environment depending on:
the type of oil spilled,
the location of the spill,
the species of wildlife in the area,
the timing of breeding cycles and seasonal migrations,
and even the weather at sea during the oil spill.
Oil affects wildlife by coating their bodies with a thick layer. Many oils also become stickier over time (this is called weathering) and so adheres to wildlife even more. Since most oil floats o nthe surface of the water it can effect many marine animals and sea birds. Unfortunately, birds and marine mammals will not necessarily avoid an oil spill. Some marine mammals, such as seals and dolphins, have been seen swimming and feeding in or near an oil spill. Some fish are attracted to oil because it looks like floating food. This endangers sea birds, which are attracted to schools of fish and may dive through oil slicks to get to the fish.
Oil that sticks to fur or feathers, usually crude and bunker fuels, can cause many problems. Some of these problems are:
hypothermia in birds by reducing or destroying the insulation and waterproofing properties of their feathers;
hypothermia in fur seal pups by reducing or destroying the insulation of their woolly fur (called lanugo). Adult fur seals have blubber and would not suffer from hypothermia if oiled. Dolphins and whales do not have fur, so oil will not easily stick to them;
birds become easy prey, as their feathers being matted by oil make them less able to fly away;
marine mammals such as fur seals become easy prey if oil sticks their flippers to their bodies, making it hard for them to escape predators;
birds sink or drown because oiled feathers weigh more and their sticky feathers cannot trap enough air between them to keep them buoyant;
fur seal pups drown if oil sticks their flippers to their bodiesk
birds lose body weight as their metabolism tries to combat low body temperature;
marine mammals lose body weight when they can not feed due to contamination of their environment by oil;
birds become dehydrated and can starve as they give up or reduce drinking, diving and swimming to look for food;
inflammation or infection in dugongs and difficulty eating due to oil sticking to the sensory hairs around their mouths;
disguise of scent that seal pups and mothers rely on to identify each other, leading to rejection, abandonment and starvation of seal pups; and
damage to the insides of animals and birds bodies, for example by causing ulcers or bleeding in their stomachs if they ingest the oil by accident.
Oil does not have to be sticky to endanger wildlife. Both sticky oils such as crude oil and bunker fuels, and non-sticky oils such as refined petroleum products can affect different wildlife. Oils such as refined petroleum products do not last as long in the marine environment as crude or bunker fuel. They are not likely to stick to a bird or animal, but they are much more poisonous than crude oil or bunker fuel. While some of the following effects on sea birds, marine mammals and turtles can be caused by crude oil or bunker fuel, they are more commonly caused by refined oil products.
Oil in the environment or oil that is ingested can cause:
poisoning of wildlife higher up the food chain if they eat large amounts of other organisms that have taken oil into their tissues;
interference with breeding by making the animal too ill to breed, interfering with breeding behaviour such as a bird sitting on their eggs, or by reducing the number of eggs a bird will lay;
damage to the airways and lungs of marine mammals and turtles, congestion, pneumonia, emphysema and even death by breathing in droplets of oil, or oil fumes or gas;
damage to a marine mammal’s or turtle’s eyes, which can cause ulcers, conjunctivitis and blindness, making it difficult for them to find food, and sometimes causing starvation;
irritation or ulceration of skin, mouth or nasal cavities;
damage to and suppression of a marine mammal’s immune system, sometimes causing secondary bacterial or fungal infections;
damage to red blood cells;
organ damage and failure such as a bird or marine mammal’s liver;
damage to a bird’s adrenal tissue which interferes with a bird’s ability to maintain blood pressure, and concentration of fluid in its body;
decrease in the thickness of egg shells;
stress;
damage to fish eggs, larvae and young fish;
contamination of beaches where turtles breed causing contamination of eggs, adult turtles or newly hatched turtles;
damage to estuaries, coral reefs, seagrass and mangrove habitats which are the breeding areas of many fish and crustaceans, interfering with their breeding;
tainting of fish, crustaceans, molluscs and algae;
interference with a baleen whale’s feeding system by tar-like oil, as this type of whale feeds by skimming the surface and filtering out the water; and
poisoning of young through the mother, as a dolphin calf can absorb oil through it’s mothers milk.
Animals covered in oil at the beginning of a spill may be affected differently from animals encountering the oil later. For example, early on, the oil maybe more poisonous, so the wildlife affected early will take in more of the poison. The weather conditions can reduce or increase the potential for oil to cause damage to the environment and wildlife. For example, warm seas and high winds will encourage lighter oils to form gases, and will reduce the amount of oil that stays in the water to affect marine life.
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The impact of an oil spill on wildlife is also affected by where spilled oil reaches. For example, fur seal pups are affected more than adults by oil spills because pups swim in tidal pools and along rocky coasts, whereas the adults swim in open water where it is less likely for oil to linger. Dugongs als feed on seagrass along the coast and therefore be more affected by oil spills.
Different resources will be needed to combat an oil spill, depending on the number and type of wildlife that is affected.
Climate Change Linked To Migratory Bird Decrease:
Biologists believe that climate change is affecting living things worldwide, and the latest evidence suggests that warmer winters may mean fewer migratory birds. New research shows that as winter temperatures have risen in central Europe, the number of migratory birds has dropped. Ultimately, this may also decrease the number of migratory bird species there.
We predict that with increasing winter temperatures…the number of long-distance migratory bird species should decline,” say Nicole Lemoine and Katrin Boehning-Gaese of Johannes Gutenberg University in Mainz, Germany, in the April issue of Conservation Biology.
The Earth’s surface temperature has increased by about a degree F since 1860, and is expected to increase by as much as 10 degrees F more over the next century. Already, climate change is affecting plants and animals in many parts of the world: for instance, plants in Europe have a longer growing season, a North American marmot has a shorter hibernation period, and some migratory birds in Europe are starting to breed earlier.
Climate change could also affect the abundance and diversity of birds. The idea is that warmer winters could increase the survival of birds that live in an area year-round, which could give migratory birds more competition for resources such as food and nest sites when they return to breed in the spring – and that in turn could decrease the total number of migratory birds as well as the number of species.
To see if climate change affects the abundance and diversity of migratory birds, Lemoine and Boehning-Gaese analyzed existing bird census and climate data for the Lake Constance region of central Europe, which includes parts of Germany, Austria and Switzerland. The researchers determined the number of land bird species and the abundance of each species during two recent census periods (1980-81 and 1990-92). The researchers considered 300 species of land birds and divided them into three categories: residents, short-distance migrants (those that migrate an average of roughly 600 to 1,200 miles) and long-distance migrants (those that migrate more than 2,200 miles). There were 122, 80 and 108 species in each category, respectively.
While climate change did not affect resident or short-distance migratory birds, Lemoine and Boehning-Gaese found that it did affect the long-distance migrants. Between the two census periods, winters got warmer and the abundance of long-distant migrants decreased. Specifically, the average temperature of the coldest month increased more than four degrees F, and the abundance of long-distance migratory birds decreased by a fifth.
Ultimately, warmer winters will probably also decrease the number of long-distance migratory bird species in Central Europe, say the researchers. In addition, the birds’ migratory behavior will probably evolve. The migratory behavior of bird populations can change in only a few generations, and several populations of wrens, skylarks and other short-distance migrants have stopped migrating in the last 20 years.
Migrating Birds Can’t Control Themselves:
During the spring and fall migratory seasons, sparrows become significantly less capable of resisting temptation. Researchers writing in the open access journal BMC Neuroscience investigated impulse control and sleep in white-crowned sparrows during migratory and non-migratory seasons. During migratory periods, the birds slept very little and became more impulsive, but sleep loss itself was not entirely to blame for their impulsivity. University of Wisconsin-Madison researchers studied the effects of migratory status and sleep deprivation on the ability of a group of sparrows to master the urge to peck at a food-giving button.
According to study director Ruth Benca, “In the wild, despite marked reductions in apparent opportunity to sleep, birds continue to successfully engage in prolonged flight, complex navigation and predator evasion during migration. In the laboratory, we’ve previously found that birds in the migratory state can learn to peck at a switch for food as well as birds during non-migratory periods. In contrast, in this study we demonstrate that, relative to birds in the non-migratory state, they struggle to learn when not to peck.”
This apparent hyperactivity during the migratory period may be linked to the fact that the migrating birds’ sleep periods become divorced from the light/dark cycle they follow during the non-migratory seasons of Summer and Winter; separate experiments showed that sleep deprivation alone does not cause this loss of control. Short sleep duration in the summer is also not associated with increased impulsivity.
According to Benca, “It is conceivable that the temporal fragmentation of migratory sleep plays a role in the migration-specific loss of behavioral inhibition. Whether the inability to inhibit pecking is related to a general failure of inhibition, a distorted sense of time, inattention to salient cues, or some other underlying mechanism is not entirely clear.”
How to Prevent Illness in Birds:
Reducing the Risk of Illness in Pet Birds
While it can be difficult to think about, the reality of bird ownership is that there are many things that can adversely affect a bird’s health in our homes, in the air, and even within the safety of your bird’s own cage. Reducing the risk of illness as much as possible is a necessity for the majority of bird owners, and can be done by working to eliminate the major risk factors in your bird’s environment. Pay close attention to the information below to help your bird ward off some of the most common illnesses that affect birds in captivity. As the old saying goes, “an ounce of prevention is worth a pound of cure!”
Practice good hygiene.
Practicing good hygiene around your bird can go a long way toward preventing the onset of illness in your pet. In addition to washing your hands both before and after you handle your feathered friend, you should also take time to make sure that your bird’s toys, dishes, and other cage accessories are cleaned and disinfected on a regular basis. Practice good cage-cleaning techniques by changing the liner at least once a day, and doing a deep, thorough scrubbing weekly. Taking these sorts of steps will help reduce the your bird’s risk of being exposed to viruses and bacteria that may find their ways into your pet’s living space.
Solution:
In BriefHuman history has followed a pattern-which began in Africa but is now global in scope-of exploiting nature and depleting resources. As we have expanded our influence over the world, we have also extinguished species and populations at an alarming rate. Despite attempts to reduce biodiversity loss, the trend is likely to continue: nearly 20% of all humans-more than a billion-now live within biodiversity hotspots, and their growth rate is faster than the population at large. This article presents nine steps to reduce biodiversity loss, with a goal of categorizing human-caused extinctions as wrongs, such as the slave trade and child labor, that are unacceptable to society. These steps include developing a system of parks that highlight the planet’s biological legacy, much as historical landmarks celebrate human history. Legal prohibitions that are fairly and capably enforced will also be essential in protecting rare and declining species. Biodiversity endowments-from national governments, nongovernmental organizations, and private enterprises-can help support parks and native species in perpetuity. Like a good sports team, conservationists need to defend extant wilderness areas, but they also need to play offense by restoring ecosystems, reclaiming keystone and umbrella species, and making human landscapes more hospitable to biodiversity. In the long run, the most effective forms of conservation will be those that engage local stakeholders; the cultivation of sustainable ecosystems and their services must be promoted along with conservation of endangered species and populations. The emerging field of ecological economics can unite these goals by revealing the connections between human well-being and conservation.
Key Concepts
Extinction is likely to be one of our longest-lasting legacies.
To address this crisis, we will need landscape-level management of wilderness and human-impacted areas, community involvement, legislation, economic incentives, bioliteracy, unified conservation science, and attention to the prime drivers of extinction: growth of the human population and its aggregate consumption.
The new field of ecological economics, which synthesizes human activities and natural processes, can quantify the costs and benefits of biodiversity protection.
We need a social transformation, through education and ecological literacy, to make human-caused extinction a thing of the past, like the slave trade, apartheid, and the Iron Curtain.
In 2008, the Royal Society for the Protection of Birds in the UK announced a final call to find the slender-billed curlew, a one-time resident of Europe, the Middle East, and North Africa, last seen in 1999. Meanwhile, scientists in Australia pronounced the white lemuroid possum extinct; a native of mountain forests in Queensland, the possum was the first mammalian extinction blamed exclusively on global warming.. Two critically endangered frog species were declared extinct, despite their protection by a Costa Rican national park. More than 140 species of mammals, 24 birds, 6 reptiles, and 5 amphibians deteriorated in conservation status, moving from lower to higher risk categories of concern on the IUCN Red List of Threatened Species, the global authority on the conservation status of the world’s animals and plants.1 Only 37 mammals improved during this period, along with two birds and one amphibian.
Unfortunately, the year 2008 was not exceptional in these respects. The biodiversity crisis is by now as well known as it is tragic. The species extinction rate is of great concern. At least 76 mammal species are known to have gone extinct since 1500, with several others on the verge.2 The baiji, a freshwater dolphin of the Yangtze, will almost certainly join the list soon. The Scimitar-horned oryx and Pere David’s deer now probably exist only in captivity. Marine mammals are in severe danger, especially in northern oceans. Things are even worse for other, less celebrated, taxa. More than 70% of North America’s freshwater mussel species are on the edge of extinction.3 Since the Polynesians first arrived on Hawaii 1,600 years ago, more than 70% of the islands’ native birds have disappeared.4 Since 1850, the extinction rate for the world’s birds has been about 100 times higher than the background rate in the fossil record. More than 10% of all bird species remain threatened. Seabirds have been in special jeopardy-rats took out many island colonies, and about 130 of the 450 remaining species are threatened with extinction-but forest birds aren’t faring much better. If deforestation continues at the present pace, so many birds may disappear that their extinction rate will increase by more than an order of magnitude by the end of the century.5
The problem is much bigger than species loss. The diversity of life spans many levels, from strands of DNA within an individual to entire ecosystems comprising billions of organisms and thousands of species. Extinction occurs adaptation by adaptation, population by population, habitat by habitat. The disappearance of a population is often a prelude to species extinction,6 but species can lose their ecological relevance long before they go extinct, as their numbers dwindle and they no longer remain key players in the system. Many extant species are now absent from more than half of their historic ranges. As organisms disappear, we lose our natural capital-the ecological goods and services that enrich and sustain our lives. That deforestation and overgrazing can lead to erosion and desertification is as obvious as the Sahel, but other connections-such as the rise of malaria and hemorrhagic fevers in disturbed lands-are becoming more apparent as our ecological footprints and understanding of diseases expand. There is a growing recognition that our natural heritage is at risk, irreplaceable, and central to our well-being.
There are potential remedies for these problems, but they will take effort and determination. The financial crisis made front-page news every day in early 2009. The global extinction crisis barely was mentioned. Yet economic recessions are a blip in history, whereas the effects of runaway extinction will linger for millions of years. Paleontologists have identified long lags in the evolution of new organisms following major extinction events, largely because diversity begets diversity. Extinction chips away at the genetic and ecological engines of speciation. With fewer genetic lineages, there is a reduction in the raw material of evolution: variation in DNA. A reduction in ecosystems and unique niches means fewer opportunities for new organisms to evolve. The drop in the number of species, genera, and families on the planet is likely to be a long-lasting legacy of human activities. We will be poorer without a rich store of biodiversity-in spirit, in health, and even in our pocketbooks. Here are nine tactics that could help moderate human-caused extinctions. Most of these suggestions have been made before, repeatedly, but they warrant our continued and ever-more-urgent attention.
Landscape
1. Biodiversity Parks
Many countries have national parks that feature special landscapes and geological formations: the volcanic caldera of Yellowstone, the Grand Canyon, Mount Kilimanjaro. In addition to these traditional and essential parks, there is a need to protect a carefully designed network of reserves on each continent and in every ocean. This global series, or archipelago, of biological refuges-biodiversity parks-will preserve key features of the Earth’s biological legacy inherited from the evolutionary past into the future. Such parks, in effect, would celebrate and honor the evolutionary heritage reflected in biological diversity, just as traditional national parks and monuments preserve special geological features or honor important historical events in human affairs. Rather than merely constructing museums that memorialize biocide, biodiversity parks would offer explicit protection for endangered species and evolutionarily distinctive ecosystems. The task is not as insurmountable as it might appear. By preserving and endowing just 25 biodiversity hotspots (less than two percent of the earth’s land area) we could help protect 44% of vascular plant species and 35% of all species of mammals, birds, reptiles and amphibians for $500 million a year7-less than 0.1% of the funds allocated to the United States’ Troubled Asset Relief Program (TARP) to bail out incompetent financial institutions.
One difficulty with many current park systems is that reserves often tend to be on residual lands that are not very valuable for resource extraction or human subsistence. A study of new reserves in Australia showed that they were typically gazetted on steep and infertile public lands, areas least in need of protection.8 Without proper planning, ad hoc reserves can be ineffective, often occupying less productive land, making the goal of protecting biodiversity more expensive and less likely to succeed. Well-placed networks of sanctuaries, designed with an awareness of ongoing climate disruption and the unique biotic facets of the sites, can help shepherd many species through the extinction crisis.
In discussing parks, we often think of landscapes, but the biodiversity crisis affects aquatic systems as well. Protection of the oceans requires safeguards against overfishing and networks of marine reserves that include rich nearshore habitats (such as coral reefs and upwellings) as well as deep-sea vents and abyssal plains. As on land, these protected areas should range from strict nature reserves where fishing and extraction are forbidden to seascapes that are managed for their cultural and ecological value. Areas that are open to exploitation should be managed sustainably to meet the long-term resource needs of local communities, while providing natural services such as recreational opportunities and water purification.9
2. Ecologically Reclaimed and Restored Habitats
Humans need to play conservation offense as well as defense. Beyond the immediate concern with the loss of a particular population, species, or ecosystem, a focus on long-term recovery and biological revival is also essential. Scientific research can inform the restoration of local habitats and help renaturalize entire ecosystems by uniting scattered fragments.
In Costa Rica, scientists, businesspeople, politicians, and the local community helped regenerate 700 square kilometers of a tropical forest system-an area assaulted by ranching, hunting, logging, and fires for almost 400 years. They purchased large tracts of land, stopped the farming and fires, and let nature take back its original terrain.10 Restoration relying on successional recovery is not always so predictable, however. The reintroduction of fire to sand barren prairies that had been overgrown with willow was not enough to restore the prairie. The woody vegetation was resistant to the fire regime.11 For that reason, restoration ecologists are often needed to ensure the recovery of degraded lands.12 Thousands of species have been eradicated or imperiled by the construction of ill-conceived dams throughout the world. It is too late for the many freshwater mussels and fish that have gone extinct, but for others the damage still can be reversed. The removal of the Edwards Dam from the Kennebec River in Maine restored large numbers of eels, sturgeon, and striped bass to upstream habitats, where they had been absent for more than 150 years. The U.S. Fish and Wildlife Service funds competitive grants for private stewardship of lands, with an emphasis on endangered species habitat. Dozens of federal grants support restoration projects such as prairie streams for the Topeka shiner in Iowa, aquatic systems for Arctic grayling in Montana, grasslands for a threatened milk-vetch and other plant species in Oregon, and habitat for sage grouse in Colorado.13
The reintroduction of individual species can play an important role in rewilding parks and their surrounding ecosystems. Large animals are especially prone to extinction, yet they are often key to ecological dynamics. The return of a megafaunal species to its historic range can yield many benefits: undo a population extinction, make habitats more interesting and exciting for locals and visitors, and restore ecological interactions (often with positive system-wide consequences). There have been several successful examples of repatriation, though far from enough. Bald eagles now nest in every state in the continental U.S., and populations have increased by more than an order of magnitude since their lows in the 1960s. Przewalski’s wild horse has been reclassified from Extinct in the Wild to Critically Endangered, with more than 300 free-ranging individuals now roaming Mongolia. After several decades of absence from the park, gray wolves released by the Yellowstone Wolf Recovery Team in 1995 produced some surprising changes: survivorship of pronghorn fawns increased fourfold, as coyote densities declined where wolves were present;14 streamside vegetation returned as elk browsing declined; and tourists flocked to the region, spawning a new type of ecotourism-wolf watching-now a $35 million a year industry.15
Some have argued that one way to restore ecological interactions that were lost with the extinction of the Pleistocene megafauna would be to introduce analogs, or modern counterparts, from elsewhere. For example, bringing Asian elephants to North America might provide seed dispersers for certain plants that co-evolved with mastodons.16 There is no scientific or ethical consensus about the wisdom of such expensive and transformative action. Yet the possibility that genetic engineers might one day be able to bring extinct megafauna such woolly mammoths to life from frozen ancient DNA17 should prompt us to consider whether, if such efforts are successful, mammoths are something worth restoring to landscapes that have not seen them in 11,000 years.
Community
3. The Fabric of Local Communities
As scholars, biologists mostly observe. They build models, experiment, and-on good days-make new empirical or conceptual connections: the effects of pesticides on egg development, the role of disease in amphibian declines, or the effects of biodiversity on ecosystem function. Such studies take place on the modest spatial scale of a Petri dish, a common garden, or perhaps a local landscape, and at the modest temporal scale of a few years. To ameliorate the extinction crisis, though, science must move beyond such focused analyses-i
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