From North To South: A Bird’s Eye View
Jane Donnelly, Coordinator of Volunteers, Central Park Zoo, New York, NY
For a number of years, there has been an on-going effort among conservation organizations, zoos and educational institutions to raise awareness about the destruction of the world’s rainforests. Happily, we observe this raised awareness at the Central Park Zoo. Teachers will often ask for a class or tour that focuses on the rainforest, because they have recently taught about it. The children will, therefore, come to the zoo well prepared and very excited by their visit to the zoo’s rainforest exhibit. They will be aware of the different layers of the rainforest and the habitat destruction that threatens the plants and animals that live there. Usually, however, they are not aware of the plight of migratory birds that winter in the rainforest and return north to breed in the spring. Likewise they are completely unaware of the habitat destruction that is happening in the Boreal or northern forests. I look forward to the day when children will come to the Central Park Zoo having just completed a unit of study on the boreal forests. I was first alerted to this issue of habitat degradation in the boreal forests by a September 23, 2003 New York Times article, “For Billions of Birds, an Endangered Haven” by James Gorman.
The boreal forests in the north and the rainforests in the south are both being subjected to habitat destruction. Neotropical migratory birds, which use both habitats, are among the first species to feel the effects. As conservationists we need to work harder at raising awareness about these forgotten northern forests. This presentation will focus on the double threat to migratory birds that results from habitat destruction in both the rainforests and the boreal forests. Although both forests occur around the globe, and similar problems exist everywhere, this presentation will be restricted to the boreal forests of North America and the rainforests of Central and South America. To make it more personal for Central Park Zoo volunteers and visitors an additional focus will be on birds that specifically migrate through New York State and New York City.
The Rainforest and the Boreal Forests
The rainforests are situated around the equatorial regions of the world, between the Tropic of Cancer (23.5 N latitude) and Tropic of Capricorn (23.5 S latitude). This 3000 mile latitudinal band is called the “tropics.”
Rainforests have considerable annual rainfalls. Temperatures are hot and vary little throughout the year. Consequently they are always hot and humid. Rainforests are known for having the greatest biodiversity on the planet. In these regions where there are 12 hour days and 12 hour nights, there is a year-long growing season.
The boreal forest biome is found between 50 and 60 latitude. The taiga biome is found near the Polar Regions just above and sometimes overlapping the boreal forest latitudes. Boreal forests (from Boreas, the Greek god of the north wind) have cold average temperatures and short growing seasons. Precipitation is mostly in the form of snow. Because of the short growing season and harsh conditions, the northern forests support a much lower biodiversity.
A Bird’s-eye View
Imagine a place called the boreal forest and an area so vast and intact that 3 billion birds gather there each year, giving it the greatest breeding-bird diversity of any place in North America. Next think of this forest as one big paper mill, being razed at a rate of five acres a minute and you can see why a unique coalition is racing to save the boreal before it’s too late. Jeff Hull
This quote says it all. Habitat destruction is well underway in the Boreal but most people are relatively unaware of the problems in the boreal forests compared to their awareness of similar problems in the rainforests.
In Alberta, for example, because of logging, mining and oil and gas drilling, only 10% of the forest is found in intact tracts larger than a few square miles. Shockingly this is down from 95% in 1960. Consequently, according to researchers at the University of Alberta, bird populations in many parts of the province have fallen by 20% 50% largely because of habitat fragmentation and destruction.
In addition to habitat degradation, climate change, due to global warming, is another problem threatening the northern forests. Like any forest, the boreal forests act to moderate climate change by serving as photosynthetic
sponges for greenhouse gases, especially carbon dioxide. This keeps the gases out of the atmosphere where their buildup is greatly hastening the rate of global warming. Boreal muskeg soils, in particular, contain the highest concentrations of carbon on earth. These peatlands have trapped 150 billion tons of carbon during the last 8,000 to 10,000 years. Peat extraction for gardening and fuel is threatening this benefit. Global warming is clearly an added stress to birds and other wildlife that are already coping with habitat destruction and fragmentation.
For Neotropical birds, including many warblers and vireos, changes in weather are partial signals to them indicating when to begin spring and fall migrations. Changes in temperature and precipitation also affect the timing and availability of flowers, seeds, insects and other food sources that the birds rely on once they reach their destinations. Studies show that the ranges of a number of bird species have been changing due to rapidly rising temperatures. Some birds are migrating earlier in spring due to these warmer temperatures. This often affects the timing and availability of the flowers, seeds and insects that they come to eat. In such cases, the “early bird” does not always get the worm.
As regional temperatures rise, the climatic ranges of a number of species in the Northern Hemisphere could shift north. Moving to different ranges, birds may face new prey, predators, and competitors as well as different habitats.
Even if they can respond quickly to climate change, the ranges of plants to which they have been historically accustomed may take centuries to move, if they do so at all. For example, New York could see a significant reduction in suitable climatic range for Cap May warblers and Bay-breasted warblers that are important predators for pest insects such as eastern spruce budworms, which can cause major damage to the state’s forests. Some states may lose their state birds from range changes due to global warming. There soon may be no Baltimore orioles in Baltimore or even in Maryland nor any Black-capped chickadees in Massachusetts or Purple finches in New Hampshire.
So, what does it matter? Why should we care?
The bottom line, the economy: bird watching involves travel and equipment and books. According to the U.S. Fish and Wildlife Service, Americans spend more than $3.5 billion yearly on birdseed, houses, feeders and baths. Birdwatchers spend an average of $100 million in each state, which in turn supports more than 200,000 jobs and generates more than $1 billion in state and federal tax revenues.
For those of us who love wildlife, we know the important roles birds play in nature, pollinating plants, dispersing seeds and eating insects. The Rufous hummingbirds, for example, are important pollinators of the wild blueberry in southeast Alaska. This pollination benefits the whole ecosystem because many other species depend on the blueberry for food.
Possibly the best reason of all why we should care is the joy birds bring, not only to avid birdwatchers, but to all of us. What a delight to wake up or to sit outdoors or take a walk in the park accompanied by a concert of birdsong! What an amazing surprise to catch a glimpse of a bird flying from branch to branch and to bring it in close with binoculars! How glorious it is that countless birds add such a delicate backdrop to our lives.
What can we do?
We can support and take responsible action to cut emissions of CO2 in order to slow global warming. We can purchase “green” automobiles and “green” energy like wind, biomass and solar power. We can make houses and buildings energy efficient using insulation and “Energy Star” rated appliances, solar panels and other green measures.
We can support measures that protect habitat. In this respect, the very first thing to do, (and it will take a determined effort) is to cancel all catalogue subscriptions and shop on line. Seventeen billion catalogues – 59 for every man, woman and child are mailed in the United States alone. Less than 5% of these catalogues contain post-consumer recycled material often from the boreal forests.
Conservation groups have protested big name offenders like Staples and Victoria’s Secret, Kimberly-Clark makers of Kleenex, Scott, Viva and Cottonelle brand tissues, toilet paper and paper towels resulting in some important successes. Visit Conservatree’s website conservatree.com for a list of ecologically friendly tissue products.
Finally, join conservation organizations, stay informed and take politically strategic action whenever possible.
As educators, it is important for to interpret this information for our visitors. At the Central Park Zoo, we are developing a chat to educate visitors. This chat will be given in a quiet tree and garden area of the zoo during
Migration Weekend. A table will be set up with binoculars and birdwatcher’s books. A large graphic will also be displayed showing a map of both the boreal and rain forests areas in North and South Americas. The Cape May warbler and the Bay-breasted warbler will be used as examples in discussing loss of habitat and climate change issues that affect migrating birds in general. These birds were selected because, if global warming continues at its present rate, they are expected to show a significant reduction in numbers here in New York State.
For Further Reading and Study
www.abcbirds.org American Bird Conservancy (ABC)
www.conservatree.com paper for a list of ecologically friendly tissue products
Audubon Magazine, “The Final Frontier’ by John Hull, Sept. 2005.
The New York Times, “For Billions of Birds, an Endangered Haven” by James Gorman, Sept. 23, 2003.
U. S. News & World Report, “Fighting for a forgotten forest” by Betsy Carpenter, Feb. 9, 2004.