Forwarded by Jane Clark

DECREASED WATER QUALITY MAY POSE THREAT TO MIGRATING WATERFOWL-SCIENTISTS 
WILL TRACK IOWA DUCKS FROM OUTER SPACE
By Lowell Washburn, Iowa Department of Natural Resources

Migratory waterfowl are currently winging their way toward ancestral nesting 
grounds.  And although millions of migrating birds will fly across Iowa 
during the next several weeks, scientists will be keeping an especially 
watchful eye on the daily activities of seventeen lesser scaup ducks.

Following their arrival on Mississippi River Pool 19 last week, the 
two-pound birds [also known as bluebills] were captured, anesthetized, and 
then surgically implanted with state-of-the-art satellite transmitters. 
Following a two-hour recovery, the ducks [all females] were released to 
rejoin the northward migration.

According to Louisiana State University Professor and project coordinator, 
Alan Afton, this high-tech endeavor will allow scientists to chart the 
scaups' migration paths, habitat use, and ultimate survival.  Although 
previous land based telemetry studies have been conducted in the state, this 
is the first time Iowa waterfowl have been monitored from space.

Afton, who has been studying scaup for more than thirty years, hopes the 
experiment will shed light into factors affecting the species' overall 
survival.  Scaup populations have waned by as much as 50 percent during 
recent years --- down from 7 million breeding birds inventoried during the 
1970s to around 3.5 million today.

"While most other duck species are holding their own or even showing an 
increase, scaup numbers continue to decline," says Afton.  "Although there 
are theories, no one can say for certain why the 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 birds arrive 
in northwestern Minnesota, they are in poor body condition."

Ongoing water quality studies have revealed that 97 percent of surveyed 
wetlands in north central and northwestern Iowa contain measurable levels of 
herbicides, pesticides, or other chemical contaminants.  Additional 
pollutants include widely-ranging levels of phosphorus and nitrogen.  Many 
researchers suspect the pollution is disrupting aquatic food chains.

Biologists note that spring migration is a time when female scaup stoke up 
on the natural aquatic foods needed to build nutrient reserves essential to 
egg production.  Failure to acquire those reserves could result in lowered 
nesting success and significant decreases in the annual recruitment of 
young.  Tiny crustaceans known as amphipods represent the scaup's most 
important food source as ducks migrate across Iowa's interior.

"For lesser scaup to maintain the healthy body condition needed for egg 
production, they must have amphipods," says DNR waterfowl biologist, Guy 
Zenner.  "Historically, it was no problem for scaup and other water birds to 
find that nutritional source in Iowa.  Today, wetland water quality has been 
compromised to the point that amphipods no longer exist in most of our 
marshlands.  Scaup end up surviving on alternate food sources which are 
insufficient to increase or even maintain critical body weights."

"It's a water quality issue and everyone living in Iowa should be very 
dismayed by these findings," added Zenner.

During the next several days those seventeen radio implanted females are 
expected to leave the Mississippi River and disperse northwest across Iowa. 
As hens continue toward the boreal forest breeding grounds of northwestern 
Canada, space stationed satellites will track and report the ducks' 
whereabouts on a daily basis.  In most instances, the information will be 
"location specific" where biologists can pinpoint the exact wetlands 
northbound scaup are utilizing.

Ducks Unlimited personnel are currently constructing a website that will 
allow the public to view the project's outer space observations.  Beginning 
mid-April, the radioed scaups' progress can also be viewed on the Iowa DNR's 
web site.  Transmitters are expected to provide data through the 2008 
migration.

"Once we pinpoint the actual 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 are using along the course of their 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," said 
Afton.

 

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