Some good news for the weekend. In California's central valley, an endangered songbird is making a comeback and showing up in places it hasn't been seen in decades, thanks to efforts at land restoration:
FRESNO, Calif. -- A chatty songbird thought to have disappeared from the Central Valley 60 years ago has been spotted nesting in a patch of restored habitat along the San Joaquin River.
The least Bell's vireo, a little gray songbird that fits in a closed fist, was once widespread in the Central Valley. It disappeared from the area as the riparian habitat it favors was ripped up to make way for development and agriculture. About 90 percent of the valley's historic riverside vegetation has been lost, said Al Donner, spokesman for the U.S. Fish and Wildlife Service.
The bird was put on the federal endangered species list in 1986, when there were only about 300 pairs left in the low-lying shrubbery along creeks and streams in southern California.
Dropping her equipment, [seasonal biologist for the San Joaquin River National Wildlife Refuge, Linette] Lina focused her binoculars on the bird -- a male perched on a branch about 30 feet away, singing and shaking his tail feathers. As she called her supervisor about the discovery, a female joined him and did a copulation dance.
Further investigation showed the nesting pair was feeding two baby birds, which were just learning to fly, said Lina, who does bird counts and observation for the Point Reyes Bird Observatory Conservation Science.
The area where they were found had been a ranch, which was bought in 1998 and restored over the last three years by Fish and Wildlife with help from the state of California.
It must be immensely satisfying for these biologists to see the fruits of the efforts of years of hard restoration work.
A blog called Toad in the Hole has an email from a couple days ago from within the federal Fish & Wildlife Service announcing this discovery. Also, Hedwig has a pointer to this story in her current edition of Birds in the News.
As a result of the destruction of much of their riparian habitat over the latter half of the twentieth century, least Bell's vireos had been confined to southern California—in particular the Camp Pendleton area in San Diego County. Habitat loss and also nest-parasitism by brown-headed cowbirds reduced the vireos numbers into the hundreds by the mid-1980s.
Fortunately, efforts to control cowbirds and preserve and restore habitat have increased the numbers of least Bell's vireos to around 3000 these days. And with that increase, they have been expanding back north into their former range. So perhaps this exciting discovery in the central valley should not be all that surprising.
For those who aren't familiar with cowbirds, here is a description of their parasitic behavior from the Audubon Society:
Instead of building their own nests, incubating their own eggs and raising their own nestlings, Brown-headed Cowbirds have a different breeding strategy. Cowbird females use other bird species as hosts -- laying their eggs in the nests of other bird species and relying on these hosts to incubate and raise their chicks.
Brown-headed Cowbirds occupy most of North America south of the Arctic, but this large range has occurred only recently and is the result of human-induced factors. Prior to the arrival of Europeans in North America, cowbirds were nomadic, following the large herds of bison that roamed across the Great Plains.
When their nests are parasitized, tiny vireos and other songbird parents end up feeding chicks bigger than they are.
Unfortunately, cowbirds are a major problem for far more bird species than just the least Bell's vireo. For instance, here in central Texas, they are a major reason why the black-capped vireo is an endangered species.
But for today at least, we can celebrate the least Bell's vireo return to its old home in California's central valley.