Keeping Tabs on Wildlife
IMAGINE having a miniature radio transmitter attached to your back so that your every move can be monitored and analyzed. Such is the lot of a wandering albatross named Mrs. Gibson. Her tiny transmitter allows researchers to spy on her by using satellites that pick up her signals—as well as those of other similarly equipped birds—and transmit them back to earth. The resulting data has produced some astonishing revelations about these magnificent birds, which, it is hoped, will contribute to their preservation.
According to a report from La Trobe University in Victoria, Australia, researchers discovered that wandering albatross fly an average of 200 miles [300 km] a day, with occasional flights of over 600 miles [1,000 km] in a day. With a wingspan of more than 11 feet [340 cm], the largest spread of any living bird, these spectacular gliders fly over the seas in a series of arcs, covering distances in excess of 20,000 miles [30,000 km] over several months. Similar studies in the United States reveal that a Laysan albatross made four treks from Tern Island, northwest of Honolulu, to the Aleutian Islands—a 4,000-mile [6,000 km] round-trip—to bring home food for its single chick.
These high-tech studies may have also revealed why the number of female wandering albatross has fallen more rapidly than that of the males. Flight paths showed that breeding males tended to fish closer to Antarctica, while breeding females usually foraged farther north, in the domain of longline fishing boats. The birds lunged for the bait set behind these boats, got caught, and then drowned. In some breeding populations, males have outnumbered females by 2 to 1. Other albatross species have also been affected. In fact, in the mid-1990’s, about 50,000 birds a year drowned behind longliners in waters off Australia and New Zealand, putting the various species at risk of extinction. The wandering albatross, in fact, has been declared an endangered species in Australia. These findings have led to changes in fishing techniques and have reduced the death toll of wandering albatross. However, the species has continued to decline in a number of major breeding grounds.
While miniature electronic devices are helping researchers to monitor certain species of birds, less expensive, more simple methods have been in use for many years. One is bird banding, which involves carefully fitting a small metal or plastic band, like an ankle bracelet, around a bird’s leg.
As a formal research tool, says Smithsonian magazine, bird banding began in 1899 when Danish schoolteacher Hans Christian Mortensen “crafted his own metal bands, inscribed with his name and address, and placed them on 165 young starlings.” Nowadays, bird banding, called ringing in Europe, is practiced internationally and provides valuable data on the dispersal of birds and on their migration habits, behavior, social structure, population sizes, and survival and productivity rates. Where hunting is permitted, banding enables governments to formulate regulations for the long-term management of game birds. Banding also reveals how birds are affected by diseases and chemical toxins. In fact, some birds can carry human diseases, such as encephalitis and Lyme disease, so data on the birds’ biology and habits can also be useful in protecting our health.
Is Banding Cruel?
Bird banding is closely regulated in the countries where it is practiced, banders usually having to be licensed. In Australia, says the Australian Nature Conservation Agency, “banders are carefully trained how to catch, handle and band birds without injuring them. Training normally takes two years and a great deal of practice.” Similar regulations exist in Europe as well as in Canada, the United States, and other countries.
Bird bands vary in shape, size, color, and material. Most bands are usually made of light materials, such as aluminum or plastic, but for long-lived birds or those in saltwater environments, stainless steel or other noncorroding materials are used. Color-coded bands allow birds to be identified from a distance. Although this means fitting a number of bands, it spares birds the stress of recapture for identification.
Whatever form of banding or marking is used, researchers are careful that birds do not experience irritation or anything that might affect their behavior, physiology, longevity, social life, ecology, or survival prospects. For example, a brightly colored marker such as a wing tag could make a bird more visible to predators or influence its mating success. Some species defecate on their legs, so banding these birds could invite infection. In cold regions, ice can build up on bands and be a potential hazard, especially for waterfowl. These are just some of the things involved in marking birds. But even so, they reveal the scope of scientific knowledge of bird biology and behavior that is required for the program to be effective and, at the same time, humane.
What if You Find a Banded or Tagged Animal?
Sometimes bands or tags may have a telephone number or an address inscribed, enabling you to contact the owner or banding authority.* You can then let the owner know where and when the tag was obtained and perhaps other details as well. In the case of a fish, for example, a biologist can then determine how far and fast it has traveled since it was tagged and released.
Thanks to the work of researchers around the world and the efforts of conscientious people who report the tags and bands they find, amazing details about wildlife are being gathered. Consider the example of the red knot, a four- to seven-ounce [100 to 200 gram] bird of the sandpiper family. Scientists now know that some red knots migrate from Canada’s far north to the tip of South America and back every year—a distance of some 18,000 miles [30,000 km]!
The band on one aged but healthy red knot revealed that it may have done this for 15 years. Yes, this little fellow may have flown 270,000 miles [400,000 km]—farther than the average distance from the earth to the moon! With this truly remarkable little bird sitting in the palm of his hand, nature writer Scott Weidensaul said: “All I can do is shake my head with mingled awe and respect for the travelers that stitch together this wide world.” Indeed, the more we learn about earth’s many creatures, the more we are filled with awe and respect for “the Maker of heaven and earth . . . and of all that is in them,” Jehovah God.—Psalm 146:5, 6.
Bands or tags can become so worn down that the details are illegible. By the use of etching, however, these seemingly invisible details can often be read. In the United States, the Bird Banding Laboratory reads hundreds of such bands every year.
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FORMS OF MARKING AND TRACKING
Many creatures besides birds are marked for study. The marking techniques employed depend on the scientific objectives as well as the physical characteristics and habits of the animals involved. Besides leg bands, researchers use flags, streamers, tags, paints, tattoos, dyes, brands, collars, radio tracking devices, microcomputers, and stainless steel darts (with coded tags attached) as well as toe, ear, and tail clipping and various other techniques and devices. Some of these are quite inexpensive. Others are more costly, such as the $15,000 miniature electronic apparatus, with camcorder, that is used to study the diving habits of seals.
An electronic device called a passive integrated transponder can be inserted under an anesthetized animal’s skin or inside its body and later read externally with a special instrument. To study bluefin tuna, scientists insert a tiny computer called an archival tag, or smart tag, into a fish. For up to nine years, these microchips collect and store data on temperature, depth, light intensity, and time. When the tag is returned, it furnishes a wealth of data, including its host’s travels, which can be calculated by comparing daily light readings with time data.
Snakes can be marked by clipping certain scales; turtles by notching the shell; lizards by toe clipping; and alligators and crocodiles either by toe clipping or by the removal of scutes (horny plates) from the tail. Some animals have sufficient natural variation in their appearance that individuals can be identified simply by photographs.
Tagging a black bear with ear tags; a spaghetti tag on a damselfish; tail tags on alligators
Peregrine falcon with a satellite transmitter
Rainbow trout fitted with an internal telemetry device
Bear: © Glenn Oliver/Visuals Unlimited; damselfish: Dr. James P. McVey, NOAA Sea Grant Program; alligator: Copyright © 2001 by Kent A. Vliet; falcon on pages 2 and 15: Photo by National Park Service; men with fish: © Bill Banaszewski/Visuals Unlimited
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Banding a sharp-shinned hawk
© Jane McAlonan/Visuals Unlimited