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World Travelers. Tiny Tags, Big Impact. Questions
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World Travelers
Semipalmated sandpipers can fly more than 3, 000 miles without stopping. No resting, no eating, no drinking — just six straight days of constant flight above a seemingly endless ocean. These small, brown-and-white shorebirds make such epic journeys twice a year, stopping along beaches and lakeshores across the United States. Many well-known sites serve as critical migration stepping stones, where the birds can recover and fuel up before the next leg of their journey.
But the sandpipers never stay for long. “The general perception is that these are North American species, but that’s not really the case, ” Mizrahi said. “These birds are only here for four months out of every year. They’re really a South American bird that visits North America to breed. ”
In the fall, sandpipers head south from summer breeding grounds in the arctic. Many of them fly directly from New England or eastern Canada to wintering grounds in the coastal marshes of French Guiana, Suriname and northeastern Brazil.
What happens to them when they finally reach this wintertime destination, with depleted fat reserves, after one of the natural world’s most grueling journeys? Scientists aren’t exactly sure. Over the past few decades, the populations of semipalmated sandpipers and other shorebirds have fallen dramatically. Recent studies suggest that several Atlantic Flyway shorebird species have experienced declines of between 50 and 90 percent within the past three decades.
Scientists theorize that loss of habitat, pollution and other factors in South American wintering grounds may be playing a major role.
“We know a lot about what happens to these birds when they come to North America, but very little about what happens when they go to Central and South America in the winter, ” Mizrahi said. “Here in the United States, we tend to take for granted the availability of information and financial resources for conservation. We assume that’s happening in other places in the world, but in places like Suriname and Brazil, limited resources tend to be focused on protecting endemic species – like keeping parrots from being captured and sold on the black market. “We’re trying to make sure there are also continuing investments in migratory species, the birds that we share across the hemisphere. ”
Tiny Tags, Big Impact
Scientists use many methods to track animal movement, including simple leg bands, radio and satellite telemetry, and geolocators. Radio telemetry is one of the oldest forms of wildlife tracking technology; in its early days biologists would attach collars with large radio transmitters to animals and then track their movements with hand-held antennas.
Technological advances have made it possible to shrink the size and cost of radio tracking devices. The current generation of nanotags, designed specifically to work on small birds that migrate long distances, can weigh less than a gram. Signals from nanotags are detected by receivers scattered along their migration routes; information on bird movements are uploaded to a central database located in southern Ontario. This international network, called Motus, alerts researchers when tagged birds pass within about 10 miles of a tower. Thousands of tags can be simultaneously deployed and tracked within the system, which currently includes more than 300 receiving stations throughout the Western Hemisphere.
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Mizrahi and his colleagues plan to set up seven new tracking stations along the coasts of Suriname, French Guiana and northern Brazil. The team also plans to nanotag about 300 semipalmated sandpipers captured near the stations.
The nanotags have a limited lifespan – about four months of battery power. But that’s enough time for Mizrahi’s team to track the sandpipers while they winter in northern South America.
“We are hoping to learn whether a bird tagged in November is still alive in March, ” Mizrahi said. “This is a key missing piece in our understanding about the relative importance of threats on the wintering grounds. Once we have these data, we can fill in the gaps in our population models. ”
Once researchers and conservation groups develop a more complete population model, they will be able to determine which factors affecting semipalmated sandpipers on their wintering grounds are driving the bird’s decline. Then parallel efforts to address these factors by other partners who share the same goals could help alleviate this stress and boost the population of the transcontinental shorebirds.
Questions
1. What are scientists at trying to find out by applying nanotags?
a. Challenges everywhere along the migration route of migratory birds.
b. The most dangerous locations along migration route of birds.
c. The actual degree of investments in migratory species.
2. What technological advances are not implemented for tracking migratory species?
a. Radio and satellite telemetry.
b. Geolocators.
c. Collars with large radio transmitters.
d. Nanotube technologies.
4. Vice president for research at New Jersey Audubon finds understanding the threats to these species at each link of the chain to be of vital importance. What evidence from the text supports this conclusion?
a. Migratory species face challenges everywhere along their migration route.
b. The pressure points along migration route are driving the decline of the species overall.
c. Conservation groups can direct resources and actions on an even basis.
5. What can be concluded about the reason for the dramatical fall which several Atlantic Flyway shorebird species have experienced within the past three decades?
a. The lack of information about birds` going to Central and South America on their wintering grounds.
b. Pollution in South American wintering grounds may be play a major role.
c. Loss of habitat in wintering grounds may play a major role.
d. The lack of information about birds` going to North America.
6. Will you characterize one of the oldest forms of wildlife tracking technology? (open answer)
7. In which way did technological advancement change radio telemetry devices?
a. Dimension decreasing of radio tracking devices.
b. Cost increasing of radio tracking devices.
c. Advancing detecting system across the main migration routes.
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8. The international network, called Motus, involves a central database, numerous receivers and tags that can be simultaneously deployed and tracked within the system. Nowadays it comprises …
a. about 300 tracking stations in the Western Hemisphere.
b. about 300 receiving stations along the coasts of Suriname, French Guiana and northern Brazil.
9. What is the main weak point of tiny tracking devices?
a. Nanotags yield weak signals.
b. Tiny tracking devices are too expensive.
c. Nanotags face threats on the wintering grounds.
d. Tiny tracking devices have a limited lifespan.
10. What cannot be concluded about the significance of a more complete bird population model?
a. Collaboration of scientists who understand the threats to these species at each link of the migration chain.
b. Finding out crucial aspects driving the semipalmated sandpipers’s decline.
c. It gives a possibility of habitat extension.
d. It gives a possibility investments in migratory species.
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