Scientists Look to Outer Space to Solve Iowa Duck Mystery
by Lowell Washburn
Posted: March 25, 2008

KEOKUK - Tens of thousands of migrating lesser scaup ducks have arrived on Mississippi River Pool 19.

Located at Keokuk, Pool 19 is the spring migration's most important stopover. Swarming northward from winter resorts in Texas and Louisiana, scaup [commonly referred to as bluebills] come here to refuel on abundant populations of fingernail clams. Once the birds have fed and rested, they will leave the Mississippi and head northwest across the continent. It is the beginning of a journey that will terminate on the remote, boreal forest breeding grounds of northern Canada.

But although the river's waterfowl concentrations are impressive, all is not well. Scaup populations are on the wane ---- down an alarming 50 percent from the 7 million breeding birds inventoried during the 1970s. Although no can say why, researchers are currently seeking the answer. During the past three years, Iowa's Pool 19 has become the focal point of intense scientific investigation as biologists attempt to unravel the mysteries surrounding the decline.

During the past week, scientists have used baited, wire live-traps to capture and mark a large sample of the river's scaup population. According to Louisiana State University professor and scaup research coordinator, Alan Afton, more than 4,500 of the ducks have been weighed, measured, and then marked with individually numbered metal leg bands. As bands are reported by hunters it will aid scientists in compiling data needed to make intelligent scaup management decisions.

For an additional group of 26 ducks, the research has been extended to a level that is literally out of this world. It's where the business as usual approach to waterfowl management ends and Star Trek begins.

Immediately following capture, this select group --- all females --- was taken to a nearby field station and surgically implanted with state-of-the-art satellite transmitters. Following a brief two-hour recovery, the ducks were released to rejoin the migration.

The purpose this high-tech endeavor, says Afton, is to allow scientists to collectively chart the birds' migration paths, habitat use, and ultimate survival. A pilot experiment was initiated in Iowa just last spring when satellite transmitters were implanted into 17 female scaup. That preliminary effort has already yielded some fascinating insight into scaup survival and the amazing distances ducks travel once they leave the Keokuk pool.

"The birds were tracked by satellite on a daily basis, and we've already gathered quite a bit of data from that initial group," said Afton. "As birds traveled north, three of the seventeen females died during migration. Most of the surviving birds ended up in the boreal forest region of northwest Canada, and one duck went all the way to Alaska."

"On average, migrating females only made a total of six stops between Keokuk, Iowa and the boreal ponds of northwest Canada. Three more females died shortly after arriving on the nesting grounds. By fall [2007] migration, five of the seventeen hens were still alive. Four of those five made it to all the way to the wintering grounds. Two ended up in Louisiana and two spent the winter in Texas. So, for the past year, there was a total of fifteen mortalities. Only two of those ducks were shot by hunters."

As this spring's group of 26, newly radioed hens departs Iowa for the nesting grounds, space stationed satellites will continue to monitor and report the ducks' whereabouts on a daily basis. In most instances, the information will be "location specific" to where biologists can pinpoint [to within feet] the exact wetlands northbound scaup are using.

"We're doing everything possible to get a handle on the things affecting this population," said Afton. "Although there are theories, no one can say for certain why the scaup decline is occurring."

"What we do know is that migrating scaup are in really good [physical] condition when they arrive at Keokuk each spring. But by the time those same birds arrive in northwestern Minnesota, they are in poor body condition."

"Once we pinpoint the exact wetlands scaup are using, we can go in and sample those locations for food," says Afton. "Once we determine what types of wetlands the birds prefer during migration, we can go in and look at the landscape features affecting those habitats. If we can identify a fairly narrow corridor that scaup are utilizing, then we can focus on improving the condition of those particular wetlands."

Ducks Unlimited has constructed an internet web site where the public can view the project's outer space observations. Beginning in April, the radioed scaups' progress can also be monitored on the Iowa DNR's web site. Providing information during both spring and fall migrations, the long-lived transmitters are expected to provide data through the 2011 migration.