Thursday, May 23, 2013
By Herb Wilson
Shorebird migration continues apace through Maine. I can't help but marvel at the tremendous migrations many shorebirds undertake. Semipalmated sandpipers depart from the Bay of Fundy and fly nonstop over the ocean to the mudflats around the mouth of the Amazon River in Suriname. The Pacific golden plover flies nonstop from Alaska to its wintering grounds in Hawaii (a nice winter vacation!). The champion is the Bar-tailed Godwit which flies nonstop from Alaska to New Zealand, a distance of over 7,200 miles.
Unlike most land birds, shorebirds tend to congregate at particular food-rich stopover areas during their migration. At these stopovers, the birds can feed gluttonously to put on sufficient fat to fuel their long migratory flights. Visiting a stopover area at the right time of year allows a birder to be wowed with large numbers of shorebirds. But this staging behavior is fraught with peril as well should an environmental disaster like an oil spill spoil the habitat.
The migration of Red Knots involves a series of stopover areas as the birds move from their wintering areas at Tierre del Fuego (the southern tip of Argentina) to the Canadian arctic. The most important stopover area for this species in the New World is Delaware Bay. The majority of Western Hemisphere knots stop here in late May to feed on the abundant eggs laid by horseshoe crabs in the intertidal regions of the Bay. These calorie-rich morsels allow the Red Knots to tank up for their next long migratory leg.
Phillip Hoose, one of Maine's own, has recently published a book on Red Knot migration, focusing on one remarkable banded bird. The book is called "Moonbird: A Year on the Wind with the Great Survivor B95." Hoose is an acclaimed writer, having won a National Book Award and Newbery Honor for his book on civil-rights activist Claudette Colvin. He also authored a book on the conservation of the ivory-billed woodpecker. "Moonbird" continues his vein of excellent, accessible writing.
Red Knots occur on all continents except Antarctica, as well as many islands. The subspecies Calidris canutus rufa is the Red Knot we see here in eastern North America. Hoose points out that conservationists are worried about this subspecies. In 1995, there were 150,000. By 2000, the population was plummeting and now fewer than 25,000 remain. Hoose explores some of the possible explanations of this alarming decline.
The star of the book is a male knot of the rufa subspecies, B95, that was banded in 1995. B95 is printed on an orange plastic flag attached to one of his legs.
B95 is a survivor, nearly 20 years old. He has been recaptured four times and observed through spotting scopes on many other occasions. Hoose rightly describes B95 as the most celebrated shorebird in the world.
We follow B95 over the course of the years, visiting the stopover areas of the species. We visit San Antonio Bay along the central Argentinian coast, Lagoa do Peixe National Park in Brazil and of course Delaware Bay.
We also learn of the threats to Red Knots along the way, including falcons, declining horseshoe crab populations and development.
We also meet conservation heroes: Patricia Gonzalez in Argentina, Brian Harrington and Amanda Dey in New Jersey, Guy Morrison and Ken Ross in the Canadian Arctic.
Hoose describes the various techniques that shorebird biologists use to capture birds so they may be banded. You are there!
B95 proves to be a marvelous tour guide and Phillip Hoose chronicles the journey in lucid, fluid prose.
The book is also accessible to high schoolers while the wonderful color photographs and figures enhance the joy of reading this work.
Herb Wilson teaches ornithology and other biology courses at Colby College and perches in South China. He welcomes reader comments and questions at: