The Sinking of the Jefferson Memorial

The Washington Post reports today that the Jefferson Memorial is having problems with stability because the land around the memorial is sinking.

The big problem seems to be a section of the sea wall that is breaking from the memorial's plaza and settling into the Tidal Basin. The "ring road" along the memorial's circumference also seems to be shifting, officials say.

Such movement is an alarming -- and chronic -- problem at the Jefferson Memorial, which was built in the late 1930s and early 1940s atop pilings and caissons sunk into an artificial mud flat that is about 100 feet deep. Engineers have been struggling for decades to keep everything firmed up.

[...]

Since then, the western section of the sea wall, which separates the memorial complex from the Tidal Basin, has dropped in places about six inches below the plaza, which it adjoins.

And the ring road, which wraps around the memorial, has also slipped several inches in spots. It is patched where it meets the plaza.

[...]

Park officials are also concerned about the flooding that for the past few years has inundated parts of the southern rim of the Tidal Basin just west of the memorial at high tide. The water covers sidewalks and landscaping and forces the park to close walkways and post signs about the high tides.

The core issue is that the monument is built on top of fill that was dredged from the Potomac River during a project to deepen a shipping channel. While the engineers took steps to ensure stability, such as driving pilings to the bedrock, the site has had problems with subsidence from the beginning. I have noticed this problem myself during my occasion walks along the Tidal Basin and Hains Point. At several points, the sidewalk takes a funny angle, does not align with the seawall, or appears to have little supporting it underneath. I am glad to see that NPS engineers are on the case.

Loose Feathers #103

Green Heron / Photo by Lee Karney (USFWS)

News and links about birds, birding, and the environment

• The Bush administration has proposed reducing the critical habitat designated for the Northern Spotted Owl. Designated habitat would shrink from the current 6,887,000 acres to 5,337,839 acres, a decrease of about 1.5 million acres. The proposed rule (pdf) is currently open for comment at regulations.gov.
• An Audubon study using the data from the Christmas Bird Count and Breeding Bird Survey revealed that many common species have declined sharply in the past forty years.
• Female Nazca boobies frequently change mates even after successfully raising chicks. This came as a surprise to researchers since staying with a single mate confers the advantage of breeding experience.
  
• The breeding ranges of North American birds are moving northward.
• A judge has blocked new grazing rules for public lands on the grounds that the Bureau of Land Management unlawfully revised regulations based on a proposal from the livestock industry while ignoring the findings of the agency's scientists.
• A young red-tailed hawk that fell from its nest gathered a crowd of onlookers in midtown Manhattan. (More at Palemaleirregulars)
• A new dinosaur precursor to birds has been discovered in China.
• Delaware's moratorium on harvesting horseshoe crabs has been overturned.
• The population of white pelicans at Chase Lake NWR has decreased from last year and returned to normal levels. Meanwhile white pelicans are nesting in increasing numbers in Wisconsin, which suggests that their range may be moving eastward.
  
• Medical researchers are using zebra finches to study stuttering in humans. An MRI study found that finches rely primarily on the right side of their brains when listening to sounds from other birds. The goal is to study how learn animals learn sounds.
• Several pigeon fanciers have been charged with killing raptors. Killing or otherwise taking birds of prey is illegal under the Migratory Bird Treaty Act.
• Gulls participated in a recent Detroit Tigers game against the Mets by feasting on moths on the field.
• Wild turkeys are not the cause of low ruffed grouse numbers in Wisconsin.
• California is threatening a lawsuit to force the EPA to grant a waiver under the Clean Air Act for the state's stricter greenhouse gas emissions standards.
• Despite its problems, ethanol is getting a major push as a renewable fuel solution in the current Congress.
  
• A genetic study of plants in Scandinavia found that Arctic plants have shifted their ranges long distances in the past in the face of changing climate conditions. The study offers some hope that organisms will be able to adapt to future climate change.
  
• The Nature Conservancy has a photo gallery of a Red-cockaded Woodpecker chick being banded at the Piney Grove Preserve in southeast Virginia. Piney Grove Preserve is the northernmost breeding population of this declining woodpecker.
  

Birds in the blogosphere

• Field of View: The importance of ANWR
• bootstrap analysis: how to detect ruffled feathers
• Bug Girl: DDT, Junk Science, Malaria, and the attack on Rachel Carson (and Part 2)
  
• Birdchick: Albino Black-capped Chickadee / Birdwatcher Crayons
  
• Greensboro Birds: Who waits for youuuuuu?
• Birdfreak: birdJam Ethics
• Tails of Birding: The Welcome Presence of the Evening Grosbeak
• Dharma Bums: Tough Love
• Blog Around the Clock: Birds are in trouble!
• Stokes Birding Blog: American Woodcock
• BrdPics: Another Photo Mash-Up
  

Carnivals and newsletters

• Friday Ark #143
• I and the Bird #51
• Simply Delightful! Carnival #2
  
• Carnival of the Green #81
  
• Birds in the News #87
  

Audubon: Common Birds in Decline

Analysis of data from the Christmas Bird Count and Breeding Bird Survey reveals that many common bird species have declined over the past forty years. The causes are varied, but most of the worst cases fall into two distinct groups. Grassland birds are under severe pressure due to the loss of old field habitat to suburban development and industrialized agriculture. Birds that breed in the far north face habitat changes due to climate change and deforestation of large chunks of the boreal forest. None of these birds is in danger of extinction at this time, but their rapid decline is still cause for concern.

Here are the twenty birds with the steepest losses in population:

1. Northern Bobwhite
2. Evening Grosbeak
3. Northern Pintail
4. Greater Scaup
5. Boreal Chickadee
6. Eastern Meadowlark
7. Common Tern
8. Loggerhead Shrike
9. Field Sparrow
10. Grasshopper Sparrow
11. Snow Bunting
12. Black-throated Sparrow
13. Lark Sparrow
14. Common Grackle
15. American Bittern
16. Rufous Hummingbird
17. Whip-poor-will
18. Horned Lark
19. Little Blue Heron
20. Ruffed Grouse

You can read more about the findings at Audubon's State of the Birds page.

(via Birdchaser)

I and the Bird #51

The fifty-first I and the Bird is now available at Birdchaser. Rob has put together a quiz so that you can win a prize if you read all of the posts. Of course, you should visit all the links anyway, since they are all great bird bloggers.

New Bird Ancestor Discovered

Palaeontologists have found a new bird-like dinosaur in China. Gigantoraptor erlianensis had a toothless beak and feathered arms and was about 26 feet long and 16 feet tall. (A skull and model are pictured at right) The fossil dates from the end of the Cretaceous Period. The large size of this species took the scientists by surprise.

Paleontologist Xing Xu of Beijing's Institute of Vertebrate Paleontology and Paleoanthropology and colleagues discovered the animal while prospecting for fossils in the Erlian Basin of the Gobi Desert in north-central China. Based on its size, the paleontologists initially classified it as member of the tyrannosaur lineage, but bits of beak, leg and other bones revealed that it more properly belonged to the oviraptorosauria group, heretofore a grouping of small, feathered creatures weighing only a few pounds. "It is the largest known beaked dinosaur," Xu says. Adds paleontologist Mark Norell of the American Museum of Natural History in New York City: "I was just flabbergasted when I saw it because it was so big."

The finding complicates the evolutionary descent of birds from dinosaurs. "Progressively from within advanced theropods you get smaller and smaller towards birds," Norell says. But "after some species originate and spring off the bird line, you get secondary gigantism."

[...]

Already, Gigantoraptor is proving very odd, according to the paper detailing the find published in Nature. It bears a ridged humerus (upper arm bone) never before observed in a dinosaur as well as an enormous but birdlike femur (thighbone). "Maybe it has some sort of birdlike running mechanism," Xu says. Norell adds: "We don't know the biomechanical advantage this would confer. But I don't think it's hopping around at that size."

See also this slideshow of Gigantoraptor images. There is more discussion from Grrlscientist.