Links from this issue's River News
Treetop Reality TV
Decorah, Iowa — More than 100,000 online viewers at any given time of day in March watched two bald eagles nesting in a tall tree in Decorah. A high-quality camera was well-positioned to give viewers an intimate view of the of incubating, hatching and feeding of three tiny eaglets. The parents moved the eggs with the gentlest nudges from their big taloned feet, and used their curved beaks to feed their fuzzy young with tweezed bits of flesh. They swapped places, hunted, brought a variety of prey — rabbit, fish, squirrel, muskrat, beaver, duck and crow — a balanced diet for baby eagles.
The camera, installed by the Decorah-based Raptor Resource Project, tilted, panned and zoomed to follow the action.
Unlike most webcams, this one broadcast sound. Breezes blew, songbirds peeped nearby, the parents talked to each other in low voices or called to announce their return, while motorcycles roared by in the distance. Their labors continued 24 hours a day, as the infrared camera attested. The pair are experienced parents, having successfully hatched and fledged two eaglets in 2008, three in 2009 and three more in 2010.
The Raptor Resource Project maintains several other webcams.
Downriver, the Stewards of the Upper Mississippi River Refuge of Thomson, Ill., placed webcams above a bald eagle nest and in a marsh near Lock and Dam 13.
The eagle nest is the second home for a pair of young eagles that began nesting about 100 yards from the current site seven years ago. High winds blew their nests down four times before the eagles moved to their current home. The Stewards has installed boards to stabilize the new nest.
The nest is visible from the road that leads to the lock and dam, but viewing the eagles via the website is better than “standing 500 feet away with a spotting scope,” said Ed Britton, Savanna District manager for the Upper Mississippi River National Wildlife and Fish Refuge.
The eaglets hatched about April 1 and likely will remain in the nest until about the end of June. Pam Steinhaus, visitors services manager, warned that some days the images from the nest get a bit shaky, depending on how hard the wind blows.
Nitrates Shrink Newts
Embryos of newts exposed to ammonium nitrate — a common agriculture chemical — were 10 percent smaller when they hatched than embryos that were not exposed to the chemical, according to a study published in the March 2011 journal Herpetologica.
The results were consistent for all levels of exposure. Smaller hatchlings are less likely to survive, face greater risks from predators and have a harder time finding food.
The study, “Realistic Levels of a Fertilizer Impair Iberian Newt Embryonic Development,” may be read on the Herpetologists’ League Journals website.
Golden Eagle Launched
Wabasha, Minn. — For two months after the release of golden eagle number 46, aka H’da Wah’pe, the big bird didn’t go far. It hunted the bluffs and prairies in eastern Wabasha County, Minn., and western Buffalo County, Wis., near where it was caught. By the end of March it still hadn’t moved north, toward its nesting grounds.
Researchers at the National Eagle Center and Audubon Minnesota had captured 46 in January, checked him out, measured him, attached a radio transmitter and released him a few days later. Their research is part of an ongoing, multi-year project to learn more about the raptors, which spend summers in the Arctic. The Golden Eagle Project has already released two eagles with transmitters and plans to release four more.
You can follow H’da Wah’pe’s long flight north, on Audubon Minnesota’s website.
It’s time to get serious about deer ticks. The river valley is considered one of the nation’s hot spots for Lyme disease.
Tiny deer tick nymphs, about the size of the period at the end of this sentence, appear from mid-May to early July in the Upper Mississippi River region. About 30 percent of them carry the bacteria that causes Lyme disease. Adult female deer ticks, about the size of a sesame seed, carry the bacteria at twice that rate, but they are easier to see and remove.
To protect yourself:
• tuck your pants into your socks;
• consider spraying yourself with a repellent containing DEET and your clothes with permethrin;
• check yourself carefully after being in the woods; and
• toss your clothes in the washer and dryer when you come inside.
Although some people suffer a rash and symptoms that go away after a couple of weeks of antibiotics, others may suffer painful and debilitating chronic problems, especially if symptoms are ignored or unrecognized. CDC Lyme disease
Dubuque, Iowa — People who want a little history and wildlife with their adventure, or vice versa, will soon get their wish on the Dubuque YMCA-YWCA’s new zipline. Suspended from safety harnesses, they will zip along at up to 20 miles per hour over the ruins of historic Union Park.
The popular park featured dance halls and amusements of all kinds during the late 1800s and early 1900s, but a flash flood in the summer of 1919 killed five people and caused extensive damage. The park never returned to its former glory, closed in 1927 and was purchased by the Dubuque YMCA.
The Y planned to open the zipline course during the summer of 2010, but construction was halted after a group of neighbors filed an appeal with the Dubuque County Board of Zoning Adjustment claiming the course was an amusement park under state law, therefore would require a special-use permit. The board sided with the neighbors, but the Y appealed to the Iowa District Court of Dubuque County.
On Feb. 21, Judge Michael Shubatt upheld the Y’s appeal, saying the zipline would not be an amusement ride but that its purpose would be educational. He gave the neighbors 30 days to appeal, but none was filed.
In April, construction resumed, said Kevin Hougham, membership and marketing director for the Y. The zipline, scheduled to open about mid-May, consists of seven cables 250 to 1,100 feet long, with viewing platforms between cables. The trip will take two to two-and-a-half hours and cost $75. Reservations are required. Dubuque YWCA-YMCA
Making Too Many Males
Minneapolis — The complicated problem of invasive, non-native fish may get even more complicated. Researchers may try to solve it by genetically modifying fish and setting them free to mate with others.
Researchers at the International Symposium on Genetic Biocontrol of Invasive Fish discussed the possibilities, risks and methods in Minneapolis last summer. An Australian researcher discussed introducing a gene that would cause carp to have only male offspring. A Florida researcher suggested manipulating sex-determining chromosomes so fish populations would become increasingly male, then decrease and be no longer viable.
A story in the Seiche, a University of Minnesota Sea Grant publication, said the “exciting potential” of these methods was tempered by the fact that most are a long ways off. Genetic biocontrol strategies can be more effective and targeted than current control methods, all of which have major flaws, according to the Sea Grant website. (Seiche, 12-2010)