Common bird species diminishing

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By MARY LYNNE VELLINGA
Sacramento Bee

Public alarm over dwindling U.S. bird populations has mostly focused on the ups and downs of a few relatively rare, hard-hit species -- the charismatic bald eagles, peregrine falcons and California condors.

Researchers for the National Audubon Society released figures this week that they say illustrate a broader, less noticed problem: the steady decline of a variety of more common birds.

Think house finches, northern pintail ducks and western meadowlarks.

Audubon Society volunteers have been counting birds every Christmas for more than a century. The national organization has compiled 40 years of this data and combined it with annual breeding season counts from the U.S. Geological Survey.

Audubon's conclusion: Some birds have experienced drastic declines that have gone largely unnoticed because their numbers are still large.

In California, for example, the number of northern pintail ducks counted by volunteers each year at Christmastime has dropped 85 percent. At breeding time, the USGS found the numbers declined by 96 percent.

The study found similarly big declines in the annual counts of horned larks, loggerhead shrikes and evening grosbeaks.

All told, more than two dozen species declined sharply in California in the past 40 years, including the killdeer, cedar waxwing, house finch, golden-crowned kinglet, Brewer's blackbird, loggerhead shrike, western meadowlark and several sparrow species.

"We're used to talking about condors and western snowy plovers and other things that we hear are in trouble, but we never hear about things that still have a population in the millions," said Gary Langham, director of bird conservation for Audubon California. "But the pintail, with a 96 percent decline, should really make us sit up and take notice.

Suburban development and changes in farming are two reasons cited for the declines. Audubon researchers also raised the possibility that diseases spread at bird feeders are affecting some species, such as the house finch.

Grassland birds, such as the loggerhead shrike and the western meadowlark, have been particularly hard hit.

"Our grasslands are disappearing very rapidly, and we can see the effect on these birds," said Ed Pandolfino of the Sierra Foothills Audubon Society. He recently conducted his own review of the Central Valley Christmas bird count numbers, and reached the same conclusions as the larger Audubon study.

"During the 1980s and '90s a lot of grassland conversion was to vineyards, which are useless for these birds," Pandolfino said. "Recently, almost all of the Valley development has been happening on grasslands.

"It's not sexy, it's not pretty, it's not old-growth forest. For most of the year around here, it's flat and brown. But it's incredibly important. It's full of birds, and those birds cannot live anywhere else."

Even though the northern pintail is a duck, it too has been affected by grassland changes. The pintail nests mostly in the wetland-dotted prairies of North Dakota, South Dakota, Montana and Canada.

The Central Valley is the wintering headquarters for 40 percent of North America's northern pintail population. But the numbers have steadily declined, attracting the concern of Ducks Unlimited, the conservation group backed by hunting enthusiasts.

"It's an elegant bird, one of the fastest flying ducks," said Jeff McCreary, regional biologist for Ducks Unlimited. "In California, we're blessed with lots and lots of them. In 1955, there were about 10 million (in North America). In the '70s, we had around 6 million. Now we're down to probably a little less than 4 million."

Pintails have been hurt by the plowing under of "pothole" wetlands in North Dakota, South Dakota and Montana for row crops, according to the Audubon report.

Fewer Canadian farmers have been leaving fields fallow, McCreary said. The pintails arrive and nest in the previous year's stubble, thinking it's prairie. Then tractors plowing the field destroy the nests.

McCreary said Ducks Unlimited is working with Canadian farmers to make the switch to winter wheat, which is growing when the pintails arrive, and makes good nesting habitat.

The effect of global warming on bird populations covered in the report is largely unknown. Researchers said it could be playing a role in the decline of the greater scaup and snow bunting, birds that nest in the Arctic.

Not all common birds are on the wane. Many species have increased their numbers or remained stable over the 40-year period. These birds can adapt to human-altered landscapes, said Greg Butcher, Audubon's director of bird conservation.

Thriving backyard species in California over the past 40 years include the American crow and common raven. The northern mockingbird population has increased slightly each year.

Some seemingly ubiquitous, invasive birds, such as the European starling and house sparrow, have actually dwindled in recent decades, according to USGS data. Originally introduced in small numbers as novelties from other countries, they may have proved more vulnerable to diseases and pests, Butcher said.

"We found that with a lot of the introduced species, they do really well for a long time, and then they start dropping," he said. "No one knows for sure why. They tend to start from a small founder population, so they may not have the genetic variability of the whole population."

The bird count data also clearly illustrate that conservation efforts pay off, Butcher said.

Raptors such as the red-shouldered hawk, bald eagle and osprey have staged dramatic recoveries since the ban on the pesticide DDT, which caused their numbers to plummet in the '60s.

With the exception of the northern pintail, many waterfowl and wading species in California also appear to be doing well. The Geological Survey breeding data lists annual increases for the American bittern, wood duck, mallard, snowy egret, black-crowned night heron and green heron.

(Reach Mary Lynne Vellinga at (916) 321-1094 or mlvellinga@sacbee.com.)

(Distributed by Scripps Howard News Service, www.scrippsnews.com.)

2 dozen types of birds in decline

By JESSICA MITCHELL Staff writer

Article Last Updated: 06/15/2007 12:31:00 AM EDT

Click photo to enlarge

The number of eastern meadowlark, top left,... (Photo and data from the National Audubon Society)

The eastern meadowlark once thrived in Connecticut's open fields, quietly nesting in the tall grasses every spring. But those days are gone.

Housing developments and suburban neighborhoods have eaten into the nesting areas of grassland birds, destroying their natural habitat and putting into sharp decline their numbers in Connecticut, according to a study released by the National Aububon Society. Grassland species like grasshopper sparrows and eastern meadowlarks are declining most rapidly, according to Milan Bull, senior director of science and conservation at the Connecticut Audubon Society in Fairfield.

In the last 40 years, the population of eastern meadowlarks has dropped by 99 percent, russed grouse by 98 percent and Baltimore orioles by 78 percent, according to Bull.

Today, fewer than a dozen eastern meadowlarks live in the Connecticut River Valley and in open fields near Bradley International Airport in Windsor Locks. Forty years ago, in a more agricultural era, Connecticut was home to thousands of meadowlarks.

"The eastern meadowlark won't ever be extinct — the population will reach a very low number but will hang on," Bull said. "Grassland habitat conservation initiatives will slow, stop and reverse the population decline. Conservation efforts will bring them back up."

Like those in Shelton. In order to conserve grasslands for bird reproduction, Thomas Harbinson, chairman of Shelton's Conservation Commission, said "the city owns parcels of land of open grasslands.

Harbinson added that meadows and grasslands are a diminishing resource up and down the eastern seaboard.

According to Bull, shrubland and woodland bird populations are in decline as well, like the brown thrasher, whose population has decreased by 99 percent, to around 1,000 birds.

Gradually over time, fewer and fewer birds are able to nest because they return from migration in the south and cannot find a field to nest in, he said.

These birds "cannot put enough new members of the population back into the population," Bull said. "[They] cannot reproduce any more because there is nowhere else for them to go."

Other rapidly declining birds, whose populations are in the low thousands, are the common tern, bobwhite quail, prairie warbler, blue-winged warblers, and salt marsh shark-tailed sparrows.

The common tern nests on offshore islands and the edges of Long Island Sound, where the colonies of eggs are disturbed by dogs or people walking on the beach.

Meanwhile, the number of typical feeder birds, such as the black-chested chickadees and morning doves, is increasing because they do well in suburban neighborhoods, Bull said. Wild turkeys also flourish in suburban areas.

According to Donna Lundgren, director of the Ansonia Nature Center, meadowlarks and bobolinks — species that nest in grasslands — are declining because there aren't as many meadows.

"Populations of birds go in increases and declines," Lundgren said. "It is not abnormal to have crashes of certain bird populations. Fifty years ago there was more farmland; now there are more lawns which are not good for birds. [Lawns] are not the tall grass meadows of farms."

Nationwide, 20 common bird species — those with populations more than half a million and covering a wide range — have seen populations fall at least in half since 1967, according to the Audubon study. The bird group compared databases for 550 species from two bird surveys: its own Christmas bird count and the U.S. Geological Survey's breeding bird survey in June.

Many of the species in decline depend on open grassy habitats that are disappearing because of suburban sprawl, the author of the study, Greg Butcher, Audubon's bird conservation director, said.

Some of the birds, such as the evening grosbeak, were once so plentiful that people would complain about how they crowded bird feeders and finished off 50-pound sacks of sunflower seeds in just a couple days. But the colorful and gregarious grosbeak's numbers have plummeted 78 percent in the past 40 years.

The Associated Press contributed to this story.

Oceans in trouble as acid levels rise

Report calls for more stringent carbon cuts to protect seas.

Corals and plankton are at risk of being destroyed by the rising acidity of the world's oceans as the waters absorb carbon dioxide from the air, British scientists have warned. The only solution, they say, is drastic cuts in carbon dioxide emissions, far beyond those called for by the Kyoto treaty.

Without such measures, dissolved carbon dioxide could increase the acidity of sea water by as much as 0.5 pH units by the end of this century, from 8.2 to around 7.7, they say. Such a change would upset the oceans' chemical balance and kill off some marine life.

"There is no way for us to remove this CO2 from the ocean. It will take many thousands of years for natural processes to remove it," said lead author John Raven of the University of Dundee, at the report's launch in London. As long as we keep putting carbon dioxide into the atmosphere, he added, it will keep finding its way into the ocean. As carbon dioxide dissolves in water it forms weak carbonic acid, which can dissolve materials such as shells and coral.

Since the beginning of the Industrial Revolution, humans have pumped an estimated total of 450 billion tonnes of carbon dioxide into the atmosphere, around half of which has ended up in the oceans, Raven said. He and his colleagues are calling for no more than 900 billion tonnes to be added during this century - a tall order given the burgeoning industrial development of China and India.

This target would call for huge cuts, with emissions by 2100 reaching half their present levels. This is far in excess of the more modest targets set by the Kyoto tr