By Deborah Huth Price For the Reporter-Herald
Posted: 04/10/2013 07:19:50 PM MDT
The lark bunting (Colorado
s state bird) depends on grasslands for survival. Breeding males are black with
white wings. (José Hugo Martínez Guerrero)
Not all birds live in trees -- many bird species depend on
open grasslands for food and shelter, and their habitat is disappearing. Some
of these little birds carry miniature transmitters and geo-locators on their
backs, helping scientists understand migratory patterns, wintering grounds and
survival needs.
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| lark bunting |
Greg Levandoski, director of operations for the
international program of Rocky Mountain Bird Observatory (RMBO), along with his
colleagues, has been studying and researching grassland birds as they migrate
from Colorado and states farther north to the
southern United States and Mexico. He
concentrates on the Chihuahuan
Desert, where he says
there are 15-17 grassland priority conservation areas that biologists and
conservationists think are the most important grasslands remaining. Their
research area covers Arizona, New Mexico, Texas and
six states in Mexico.
According to RMBO information, the Chihahuan desert
provides primary wintering grounds for more than 90 percent of grassland birds
in western North America. These range from
raptors to songbirds, including the Baird's and grasshopper sparrows, mountain
plover, Ferruginous hawk, western meadowlark and Colorado's state bird, the lark bunting.
RMBO has about 140 species of grassland birds in their database, and focus on
about 30 high-priority species that either benefit from or require grasslands.
Follow the Birds
Learn more about migratory birds by attending the
International Migratory Bird Celebration May 11 in Fort Collins: . The event includes bird
banding stations, activities, and a bike, bird and brew tour.
"It's hard to help them and conserve them if you
don't understand their needs," says Levandoski. To do this, RMBO has
acquired grants and established partnerships with organizations such as the
city of Fort Collins, U.S. Fish and Wildlife Service, Neotropical Migratory
Bird Conservation Act, the Universidad Autnoma de Nuevo Leon in Monterrey, Mexico,
and other organizations and agencies.
In order to better understand the birds' migratory paths
and preferred wintering grounds, Levandoski says researchers captured and
placed tiny radio transmitters on Baird's and grasshopper sparrows. "We
have people out in the field every day with an antenna and a headset and they
listen for little beeps broadcast by the transmitters."
A newer technology allowed researchers to use geolocators
on black swifts. These small light sensors are attached to birds' backs and
record daylight length and intensity. "Using calculations similar to those
mariners used to make, you can figure out latitude and longitude,"
Levandoski explains. The instruments do not transmit data, but store
information, which is then collected by recapturing birds the next year.
Geo-locators are now getting small enough that Levandoski hopes they may soon
be used on sparrows.
Grassland birds vary in their migratory ranges. Baird's
sparrows breed in North Dakota, Montana and the Saskatchewan
areas, flying south to Mexico
in the winter. Grasshopper sparrows are much more widespread, shares
Levandoski. "We have them on city properties breeding in summertime."
These and many other seed-eating birds need a large network of grasslands to
exist and thrive. Levandoski says that "Of all the groups of birds on the
continent, probably worldwide, grassland birds have been the most affected and
have had the most widespread population decline."
"One of the important lessons we've learned,"
says Levandoski, "is that due to the random nature of where rain falls
each year in the desert, it's really important that we conserve a whole network
of grasslands. Many of these species seem to shift the bulk of their wintering
populations year to year depending on where the rain fell and where grass is in
good condition."
