DC Audubon Society blogs

How Phalaropes Eat

John Beetham — Fri, 16 May 2008 09:58:33 -0500

Birders know that phalaropes have some unusual traits. Unlike most other bird species, female phalaropes wear more colorful plumage than males. They also have an unusual foraging technique. Most shorebirds walk on mudflats or in shallow water and pick out bits of food. Phalaropes, on the other hand, swim to forage and spin around to stir up prey. New research reveals one more foraging secret: using water's surface tension to drive food into their mouths.

Phalaropes start their meals by spinning in circles on the surface of the water. The motion creates an upwelling that draws suspended crustaceans and other tiny invertebrates within reach of the birds' beaks.
The birds then peck at the surface of the water, capturing their prey embedded in small droplets. But since their beaks are pointed down, the birds must overcome gravity to get the food into their mouths.
Bush and colleagues found the birds accomplish this by opening and closing their beaks rapidly, each step propelling the drop closer to their mouths.
When the beak closes, the edge of the drop closest to the mouth shoots even closer while the other edge stays put. When the beak opens, the trailing edge catches up while the leading edge stays put.
"This works in the presence of gravity to overcome gravity," Bush said.

Read the rest.

Polar Bears Listed As Threatened Under Endgangered Species Act

mpfaffko — Thu, 15 May 2008 07:04:40 -0500

The Polar Bear is now listed as a threatened species under the Endangered Species Act. The U.S. Fish and Wildlife Service made the announcement yesterday, 14 May 2008, with the disclaimer that the decision should not be “misused” to regulate global warming. Originally set for January, the decision was postponed, probably to allow the approval of oil and gas drilling in the Chukchi Sea which was approved earlier this year. The Chukchi Sea is home to approximately 20 percent of the world’s Polar Bears. Environmental groups praise the decision because the Polar Bear is the first species to be listed because of its link to global warming. However, I believe that Elkhorn and Staghorn Coral were the first species to be listed because of their link to global warming. Two-thirds of the world’s remaining 20,000 Polar Bears are projected to disappear in the next 50 years because of melting sea ice. Polar Bears spend most of their life on sea ice rather than land where they catch seals.

Ft. Reno Park Closed for Testing

John Beetham — Wed, 14 May 2008 15:34:47 -0500

Any birders thinking of visiting Ft. Reno Park in NW DC should be aware that the park has been closed for arsenic testing.

"Upon learning of recently reported high levels of arsenic from United States Geological Survey satellite imaging reports," the park service said, it "moved immediately to close Fort Reno Park to the public with snow-fencing being set up around the perimeter of the park."
The park, at Chesapeake Street and Nebraska Avenue NW in the Tenleytown neighborhood, near Woodrow Wilson Senior High School, is a popular site for soccer and other sports as well as concerts. It was shut down about 6 a.m. today.
The satellite imaging was done as part of the Geological Survey's "on-going work in the Spring Valley section of upper Northwest Washington with the U.S. Army Corps of Engineers," the Park Service said in a statement.
The imaging report, "while not specifically focusing on Fort Reno Park, revealed that the Fort Reno Park grounds contain arsenic levels in the soil and that the levels . . . exceed the U.S. Environmental Protection Agency's safety threshold," the Park Service said.

Update: Testing revealed high levels of arsenic, so the park will remain closed.

Fort Reno Park, near Woodrow Wilson High School in the Tenleytown neighborhood, was closed at 6 a.m. Terry Slonecker, a scientist with the U.S. Geological Survey, said he informed the D.C. Department of the Environment that soil samples contained arsenic levels up to 25 times higher than federal regulations allow.

"The official guidelines say that anything above 43 parts per million must be removed on a time-critical basis," Slonecker said. "We had several samples up there in the hundreds: 400, 500. The high end was 1,100 parts per million."

After receiving the report late Tuesday, D.C. officials informed the National Park Service, which runs the site. In a statement, the Park Service said it "moved immediately to close Fort Reno Park to the public with snow fencing set up around the perimeter." ...
An environmental scientist with the D.C. government, speaking on the condition of anonymity because he is not authorized to comment publicly, said the high arsenic levels at the park might date to the Civil War era, when the site was a fort. He said that at least 72 soldiers were prepared for burial by morticians at old Fort Reno and that "compounds containing arsenic were used as embalming fluid."

He said herbicides, pesticides and lawn fertilizer used in the park over the years also could have contributed to the contamination.

Spring Valley, another area in NW Washington, also has arsenic contamination from weapons stored there during World War I.

U.S. Ranks Last in Green Habits

John Beetham — Wed, 07 May 2008 13:36:00 -0500

Americans ranked last in a worldwide survey of environmental practices:

Americans were least likely to choose the greener option in three out of four categories — housing, transportation and consumer goods_ according to the assessment. In the fourth category, food, Americans ranked ahead of Japanese consumers, who eat more meat and seafood.
The rankings, called "Greendex," are the first to compare the lifestyles and behaviors of consumers in multiple countries, according to the National Geographic Society....
India and Brazil tied for the highest score — 60 points out of a hundred. U.S. consumers scored 44.9.
In between, China scored 56.1, Mexico 54.2, Hungary 53.2, Russia 52.4, Great Britain 50.2, Germany 50.2, Australia 50.2, Spain 50, Japan 49.1, France 48.7 and Canada 48.5.
Results are based on 1,000 online respondents per country interviewed in January and February by GlobeScan, an international polling firm based in Toronto.

If you are curious how you would score, National Geographic provides a simplified calculator. I filled out the calculator and scored a 56. My score would probably be slightly higher for summer months, when more of my food comes from local sources, and slightly lower in the winter, when it has to be transported greater distances.

Ban on Exotic Snakes to Protect Native Birds

John Beetham — Tue, 06 May 2008 13:18:00 -0500

The U.S. Fish and Wildlife Service may ban the importation or sale of large exotic snakes such as pythons and boas. It has authority to do this under the Lacey Act.

Long-lived snake species with high reproductive output, such as the Burmese python, have great potential to proliferate rapidly, and quickly expand from their place of introduction. They represent a potential ecological and economic disaster with the capacity to quickly overtake even the most far-reaching eradication efforts to protect endangered species. Recently released climate maps by the U.S. Geological Survey indicate that the Burmese python could find extensive suitable habitat, comparable to the size of its native range in Asia, in the southern one-third of the lower 48 States. Should these snakes become more widely established they will further exacerbate the threat they already pose to the health and abundance of many bird species.
According to a recent study of the stomach and lower gastro-intestinal tracts of 56 Burmese pythons captured in or adjacent to Everglades National Park, 50 were found to have eaten many bird species, including Anhinga, American Coot, Pied-billed Grebe, Limpkin, King Rail, Purple Gallinule, Great Blue Heron, White Ibis, Red-winged Blackbird, Virginia Rail, Great Egret, Magnificent Frigatebird, Clapper Rail, and House Wren. The White Ibis and Limpkin are Florida Species of Conservation Concern, and the King Rail and the Clapper Rail are on the ABC/Audubon WatchList of species in need of immediate conservation attention.

500 Ducks Trapped in Oil Waste

John Beetham — Fri, 02 May 2008 13:28:09 -0500

The Alberta Tar Sands mining projects have long been identified as a threat to boreal birds by the Boreal Songbird Initiative. Extraction of oil from tar sands requires an energy and water-intensive development process, which releases large amounts of greenhouse gases into the atmosphere. Since much of the tar sands sit underneath the boreal forest, their extraction also involves habitat destruction. This week, an incident showed another type of environmental harm when 500 ducks landed and drowned in a pond filled with oil waste. Few birds survived.

"A completely oiled bird would likely sink immediately. We've recovered the ones that we could," said Steve Gaudet, a Syncrude staff member managing the recovery effort.

The company has said it normally has bird deterrents deployed on the three-kilometre-wide lake of waste from early spring until late fall. But the noisemakers and scarecrows were not in place because of the harsh winter weather last week, officials said.

The ducks involved were not identified to species in the article. A picture accompanying the article appears to be of an Anas sp. If anyone knows more about their identity, please leave a comment.

See also Ducks Per Gallon for more context.

Update: This is not the first time that birds have been found dead at a tar sands tailings pond:

-At least 15 species of waterfowl have already been documented as having been killed on Syncrude Tar Sands tailings ponds along with an amazing 22 species of non-waterfowl.
-Research at tailings ponds in the late 1970's based on once a week surveys of two Syncrude tailings ponds observed at least 100-300 birds killed annually. Since this was based only on birds observed floating or on the sides of the ponds once a week there was clearly a larger number of birds that sunk or were unobservable so these numbers represent a minimum mortality from only two tailings ponds.
-At single tailings pond sites, research has documented tens of thousands of waterfowl and other wetland-dependent birds migrating over in periods of weeks during spring and fall migration.
-Based on research at the Alberta tar sands tailings ponds it is well documented that birds are most likely to land on the ponds at night, under weather conditions that restrict visiblity and when surrounding natural lakes and ponds are frozen under such conditions there is a very high risk of large numbers of casualties because waterfowl and shorebirds and other wetland dependent birds normally travel in flocks that can regularly number into the hundreds and sometimes into the thousands or tens of thousands. The conditions under which these large mortality events are likely to occur are also periods when it is unlikely that the ponds are monitored in order to observe mortality events. Because of this it is highly likely that mortality events like this may have occurred more frequently than reported.

For a Healthy Chesapeake, Use Less Chemicals

John Beetham — Fri, 02 May 2008 09:25:21 -0500

Maryland's Department of Agriculture has launched a campaign to persuade the state's homeowners to change how they use chemicals around their homes. Fertilizers contain nitrogen and phosphorus. When these wash into the watershed during rainstorms, they contribute to the Chesapeake Bay's summer dead zones.

Maryland still has more fields than lawns, with about 1.4 million acres in agricultural use and 775,000 acres of lawns. But state officials say fertilizer use in the state is almost equally shared between agriculture and lawn care -- which means home gardeners could learn a thing or two about conservation from farmers.

"Gardeners are using more fertilizer, and farmers are using less," explained Buddy Hance, an assistant secretary at the Department of Agriculture, which invited reporters to its Annapolis headquarters today to show off conservation practices farmers use that translate to backyard use.

It is possible to reduce or eliminate fertilizer use and still have a healthy lawn or garden. One alternative is to use homemade compost, which also reduces the amount of trash going into landfills. See the linked article for more suggestions for reducing impact on the bay.

Ferreting Out Predators

John Beetham — Tue, 29 Apr 2008 07:15:18 -0500

When we think of animals with a good sense of smell, we typically think of the Class Mammalia. Dogs, for example, are well-known for their ability to pick up and follow scents over long distances. With the exception of some vultures, birds generally are not known for this ability. The conventional understanding is that birds have only a weak sense of smell.

Some new research may change that understanding. Smell could provide a useful tool to lower the risk of predation, if birds could use it. Such a smell would be especially helpful during breeding season to warn of potential nest predators. To find out whether birds use a sense of smell, researchers studied a colony of blue tits (Cyanistes caeruleus) in Spain.

The researchers carried out an experiment with a population of blue tits that raise their young in nest boxes in Miraflores de la Sierra in the Sierra de Guadarrama mountains, in Madrid province. The researchers placed the scent of mustelids (ferrets) inside the nest boxes when the chicks were eight days old, and “the parents took longer to enter the boxes to feed their chicks, and they approached the boxes more often without going inside,” Ms. Amo de Paz told SINC.
Thanks to the images captured by a video camera located several metres from the nest box, the scientists were able to work out the number of times the chicks were fed, and deduced that the birds did not feed their chicks on fewer occasions, although “they spent less time inside the nest while feeding their babies,” according to the biologist. By spending less time in the nest box, the parents lessened the risk of predator attack while still feeding their chicks.

As a control, the researches also added a quail scent to some nest boxes and water to other boxes. The quail scent and water did not deter the parent tits to the same extent as the ferret scent. The researchers later checked all the nestlings again to see if the presence of a "predator" had impaired their physical development. The ones in the ferret-scented boxes were just as healthy as the ones in other boxes, so their development did not suffer as a result.

So does this new information have implications for helping baby birds? There is a common concern that picking up a baby bird or handling its nest might cause the bird's parents to abandon their young. Typical advice reassures people that this is not the case, sometimes with a comment that birds will not smell their touch.

In light of this study, the latter part seems mistaken; at least some birds use their sense of smell to avoid predators. However, the basic advice is correct. Even though the tits in the study sensed the presence of potential predators and were more cautious around the nest, their urge to care for their young was stronger, and they still fed the baby birds. The brief handling necessary to place a nest back into a tree or move a fledgling out of harm's way is unlikely to discourage parent birds from returning.

Six Things Birders Can Do to Help the Earth

John Beetham — Tue, 22 Apr 2008 11:03:57 -0500

Since today is Earth Day, many newspapers and websites are publishing lists of things that people can do to help the environment. Birders can do plenty of things to help the birds we love and reduce our contribution to global warming. Here are a few.

If you own property, convert as much as you can to wildlife habitat, following the suggestions of Audubon at Home and the National Wildlife Federation. At the very least, do not use artificial fertilizers and pesticides or overwater your lawn. Runoff from these chemicals harms our bays and estuaries and has been a major cause of the Chesapeake Bay's decline.
Drink shade coffee instead mass-market coffee to preserve winter habitat for migratory birds. (See the informative Coffee and Conservation blog for more about this.)
Become politically active. Birder's World suggests contacting legislators about some current issues, including the destructive border wall. Get involved in local environmental issues as well.
Reduce electric power consumption. Much of our electricity comes from burning coal, the extraction of which destroys habitat.
Bird locally and use public transportation where possible.
Carry your purchases in reusable bags instead of plastic bags.

If you are looking for other options, see this sustainability primer or the newly revised 50 Simple Things.

How Migratory Birds Lose Their Way

John Beetham — Wed, 16 Apr 2008 11:39:18 -0500

About a month ago, NickL (the Birdist) interviewed me on the subject of extralimital birds. We speculated about the number of extralimital species that arrive in North America and how they arrive off-course. Last week an article shed more light on why birds get lost. Scientists in Europe studied the physical dimensions and migratory patterns of 38 species of songbirds. Their goal was to test two competing potential causes for vagrancy. Do extralimital birds have faulty navigational instincts or are they blown off-course by the weather?

Eight species from the leaf-warbler family and six from the thrush family caught the scientists' attention as vagrants. One species that was spotted particularly often was the Yellow-browed Warbler (Phylloscopus inornatus), which was reported by voluntary ornithologists in Central Europe around a thousand times between 1836 and 1991. This species breeds in the Siberian taiga south of the Arctic Circle and overwinters in the subtropics and tropics of South-East Asia. The other Asian leaf-warbler species were observed much less frequently, if at all, in Central Europe.
By contrast, five thrush species were reported nearly 100 times. If vagrants were brought by the weather, smaller birds should be blown off course more frequently than larger ones. However, using statistical analyses, the researchers were unable to find any correlation between the frequency of vagrants and their body size. In addition, the Yellow-browed Warbler occurs far too regularly for every sighting in Central Europe to be explained by 'unusual' weather conditions during migration.

While vagrancy failed to correlate with weather patterns or body mass, it did correlate with population size. Birds with the largest breeding populations or ranges in Asia were the most likely to turn up in Central Europe. Thus it seems more likely that extralimital birds simply have faulty direction-finding abilities, which would be caused by genetic mutations.

One interesting result is that, despite their navigational disabilities, vagrant birds retain their instinct for how far they should fly. Birds that mistakenly wintered in Central Europe were typically about as far from their breeding grounds as they would have been in Southeast Asia.

Unfortunately we do not know what happens to these vagrant birds. No banded birds have been recovered subsequent to vagrancy, so the researchers believe that the birds fail to return to their proper breeding grounds. Given the low rate of band recovery overall, I am not sure we can conclude this with any certainty. However, it does stand to reason that a bird with faulty directional instincts would also have trouble finding its way back.

(crossposted)