Using Doppler Radar to Save Songbirds
Millions of neotropical migratory songbirds fly over North America on their annual northern spring migration from wintering grounds in Mexico, Central America, South America and the Caribbean to nesting grounds in the United States and Canada. Research shows that a number of these species have been declining drastically over the past 30 years, but conservation ornithologists are using Doppler technology including Weather Surveillance Radar (WSR) as a tool to help save them.
The drop in songbird populations is mostly due to habitat loss, which is evident in the birds' breeding and wintering grounds, as well as in the places they stop to rest and refuel along their migration routes. WSR can provide extremely cost-effective estimates of the numbers of birds in the air over huge areas, along with information about flight speed and direction. Analysis of the radar images can lead to identification of key stopover habitat.
The Nature Conservancy is exploring cutting-edge technology like WSR to pinpoint and protect these critical places so that songbirds can have a better chance of survival.
How It Works:
Many birds migrate at night, avoiding predators, and making them difficult for people to see, but birds do appear on WSR. What looks like a massive storm on radar is often a flock of birds ascending into the air — important information for scientists trying to determine where the birds have rested before that night's leg of their trip.
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Doppler radar reflects off the moisture in birds' bodies — simply think of them as giant raindrops.
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While Doppler radar can't tell you what species or numbers of birds are involved, it can tell you the total amount of "reflectivity" in the air at one moment.
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Doppler radar can tell the direction and speed of movement of the targets it finds. Rain and insects tend to move with the wind, so targets with velocities different from windspeed are most likely birds
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On the map, magenta represents the highest concentrations of birds and green represents the lowest.
Yellow-headed blackbird |
Migratory Bird Facts:
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More than 300 bird species, almost half of all those nesting in the United States and Canada, are migratory.
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Migratory birds play an important role in seed dispersal and pollination, and they aid agriculture by eating insect pests.
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Birds fly an average of 15-45 miles per hour during migration.
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Most migratory birds fly between 2,000 feet and 3,000 feet above sea level, but others have been tracked as low as 500 feet above sea level and as high as 20,000 feet above sea level.
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The longest migrations are more than 24,000 miles round trip per year.
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The American golden plover is so efficient it can fly for about 48 continuous hours on less than two ounces of body fat.
