The Plight of the Yellow-Billed Cuckoo
trees tall, thick and dense, let the water run free -- and the cuckoos will
big part of what the rare, potentially protected Western yellow-billed cuckoos
needs in the way of living space, says a researcher who has studied the elusive
birds for 20 years.
require native (riparian) habitat – cottonwoods and willows, tall trees, 15 to
40 feet tall,” said Matt Johnson, who works for Northern Arizona University and
also has researched the cuckoo for the United States Geological Survey.
important is that the treetops have thick, dense canopy cover of tree foliage
up high, said Johnson, director of NAU’s Colorado Plateau Research Station.
This is important for many birds, not just cuckoos, to hide nests from
predators, and to moderate daytime temperatures, shielding the birds from the
brutal desert sun, said Christopher Calvo, a research biologist who works with
Johnson at the Colorado Plateau station.
Fish and Wildlife Service recently proposed to list the cuckoo as a threatened
species, potentially triggering a suite of protective measures if the bird is
listed – or a huge conflict pitting environmental interest groups against
development and other business interests over whether it should be listed.
Johnson’s view, one of the biggest problems plaguing the cuckoos in the U.S. is
that over the last three or four decades, the dams built during the 1950s, ‘60s
and ‘70s across many Southwestern river corridors wiped out much of their
historic cottonwood-willow breeding grounds.
causes of riparian habitat loss are the conversion of these areas for farming
and other uses, water diversion, stream channelization projects to straighten
the rivers and livestock grazing, scientists have said. Groundwater pumping and
non-native plant invasions have also taken their toll on streamside plant life.
areas with dams just became a canal. They lowered the water table so low that
the cottonwoods and willows can’t tap into it,” Johnson said.
unknown what, if any problems the bird has encountered in its South American
wintering grounds, Johnson said. They spend seven to eight months annually down
there. But due to lack of research, researchers aren’t sure what habitat they
occupy and how much other factors such as pesticides may affect the birds, he
. . . What
researchers have learned is that habitat changes can clearly affect cuckoo
populations. Because the Lower Colorado River, for instance, is an area that
has been part of a federal habitat conservation plan, authorities have started
restoring some of the river’s vanished cottonwood-willow stands over the past
cuckoos have started breeding in those restoration sites in the past five to
six years, including areas south of Cibola National Wildlife Refuge north of
Yuma, Johnson said. The same phenomenon has occurred at the Palo Verde
Ecological Reserve just north of Cibola and at the Ahakhav Tribal Preserve
along the Lower Colorado outside the riverfront town of Parker, he said.