GHHC News Archive

All Things Considered, May 26, 2008 · The number of lesser scaup ducks is dwindling, and it could be an invasive species that does them in. Invasive snails and parasites are attacking these and other ducks on the Upper Mississippi.

U.S. Fish and Wildlife Service officials say with no natural predators, the snails and the parasites are thriving, and killing off a duck population that is already in trouble.

The agency has made a huge effort to create more and better habitat for the shrinking duck population, but it may be for naught.

As with a lot of other invasive species, once the creatures take hold, it's a challenge to get rid of them.

Nearly 150 invasive species live in the Mississippi River Basin, and while not all of them are destructive to native habitat, this snail has become a duck killer: The snail has helped kill nearly 50,000 ducks in the last few years in the Upper Mississippi Wildlife Refuge, which borders Wisconsin, Minnesota and Iowa.

The area is a rest stop of sorts for more than 450,000 migrating ducks every year, which snack on wild rice and snails. Pools on the river provide safe havens for birds from hunters.

Three types of invasive intestinal parasites are killing the birds.

"All three use an invasive snail, called the mud bithynia, or faucet snail, as an intermediate host," said Jim Nissen, who works for the Fish and Wildlife Service.

The snail slowly made its way from New England. Waterways along the Great Lakes played a role. In another circumstance, the faucet snail might be a new dish on the menu for ducks.

But Nissen says when the ducks eat these snails, the parasites they carry bore into the ducks' intestinal walls.

"They gorge on blood and then lay eggs," Nissen said. "The eggs are passed through the birds' feces, and that's how they reach the snails. That's how the cycle is perpetuated."

The lesser scaup duck is particularly susceptible to this parasite, killing them only in a few days. Their bodies litter the water like decoys. There were eight million lesser scaup in North America in the late 1970s now their numbers have dropped by half. Nissen worries that this snail-parasite duo could spell the end of the lesser scaup.

The snail and the parasites have been found as far south as Dubuque, Iowa, near another bird hot spot. In Texas, the invasive apple snail is thriving on wild rice beds. That's also duck food — and those snails, too, carry an intestinal parasite that is fatal to ducks.

Biologists have tried 15 poisons on the snails. Nothing has worked.

Scientists are currently redesigning islands on the river in an attempt to make them less hospitable to the snails. They're also hoping the ducks can develop a resistance to the parasites that live in the snails that they find irresistible.

To date, seven hens with operating transmitters remain alive. This includes 2 instrumented in 2007 and 5 instrumented in 2008. We continue to receive intermittent signals from an additional hen from 2007. Since the last update, one transmitter either failed or the hen died, and one hen was shot by a Cree hunter in Waskaganish, Quebec in early May. We hope to recover that transmitter from the hunter. I have attached a map of the latest movements. One interesting note: a 2007 hen (72791) has now reached almost the exact coordinate where she spent the summer of 2007 – probably a good indication of a nesting area.

Specific movements include:

44677: On 4/25 moved from Kincardine, Ontario to Lac la Belle, WI on Lake Superior. On 5/5 moved to Lake Elsie NWR in North Dakota. On 5/10 moved to Arrowhead NWR, North Dakota. On 5/11 moved to the area of the Swan River, Manitoba. On 5/12 moved to Peesane, Saskatchewan, where it remains to date.

44690: 44690: On 4/25 moved from Tonowanda State WMA, NY to south of Sault Ste Marie, Ontario. On 5/3 moved to Seney National Wildlife Refuge, Michigan. On 5/5 reached Echo Harbor, Huron Bay, Lake Superior, Michigan. On 5/7 located near McMunn, Manitoba. On 5/12 was at Pelican Bay, Lake Winnipegosis, Manitoba. On 5/17 located near Split Lake, Manitoba where it remains to date.

45893: On 4/27 moved from Campden, Ontario to East of Warner, Ontario. On 5/2 moved to West of Waskaganish, James Bay, Quebec. Shot by Cree hunter on 5/8.

55010: On 4/26 moved from Gainesville, Wyoming County, NY to west of Waterford, Ontario. On 5/7 moved to Hammond Bay, Lake Huron, Michigan. On 5/9 moved to Caribou Island, Lake Superior, Michigan. On 5/10 reached to Gull Bay, Ontario. On 5/15 moved to Wigwascense Lake, Ontario. On 5/16 moved to Wunnummin Lake, Ontario. On 5/20 moved to Big Trout Lake, Ontario where it remains to date.

55019: On 4/23 moved from Mount Forest, Ontario to Lakelet, Ontario. On 4/25 reached Kenogami River Basin, Ontario. On 4/28 was near Kapuskasing, Ontario. On 5/2 was near Opasatika, Ontario. On 5/17 was west of Kenogami River, Ontario. On 5/19 reached Atikaki Wilderness Provincial Park, Manitoba, where it remains to date.

63004: On 4/27 moved from the Currituck Sound, NC to the Rappahannock River, Richmond County, VA. On 5/8 moved to the Lackawana River, near Scranton, PA. On 5/21 reached the Thousand Islands, St. Lawrence River, NY where it remains to date.

72791: On 5/2 moved from the Mississippi Headwaters State Forest, Beltrami County, MN to Agassiz National Wildlife Refuge, MN. On 5/12 moved to Lake Winnipegosis, Manitoba. On 5/15 reached the Saskatchewan River, southwest of Root Lake, Manitoba where it remains to date.

72793: On 5/6 moved from Saint Clair National Wildlife Area, Lake Saint Clair, Ontario to Pukaskwa National Park, Ontario. On 5/6 reached Wabakimi Lake, Ontario. On 5/9 was near Gimli, Manitoba. On 5/15 moved to Berens Island, Lake Winnipeg, Manitoba. On 5/18 was located west of Kinusisipi, Playgreen Lake, Manitoba where it remains to date.

Wigeon Satellite Tracking Study..From Doug Howell NCWRC
May 2008

In February we instrumented an additional 10 wigeon with solar satellite transmitters. Two hens remain active from those we instrumented in 2007 (72791, 72793) and we continue to receive intermittent signals from an additional hen from that same year. For those birds deployed in February, 7 transmitters are active, we have had one confirmed mortality and 2 transmitter failures (although I expect one of these could possibly begin to transmit again). I have attached a map of the latest movements as of 4/21. I also attached a movement map from the same time last year (Compare 72791 and 72793 from each year). If anyone does not want to receive future updates, just holler and let me know.

Specific movements include:

44677: On 3/2 moved to north of Welchville, NJ. On 3/26 moved to Cicero WMA, NY. On 4/10 moved to Amherst Island, Ontario. On 4/11 moved to Kincardine, Ontario where it remains to date.

44688: On 3/2 moved to east of Mystic, CT. On 3/3 located at Cedar Swamp, south of Carver, MA. On 4/4 moved to the area of Great Cedar Swamp west of Monponsett, MA where it remained until 4/16 when the signal was lost.

44689: Transmitter failed only hours after deployment. Bird observed alive weeks after failure but not recaptured.

44690: On 2/26 moved to Prime Hook NWR, DE. On 3/7 located on Little Creek State Wildlife Area, DE. On 3/15 moved to New Garden, PA. On 4/5 located south of Lake Ontario in Hamlin, NY. On 4/7 moved to Tonowanda State WMA, NY where it remains to date.

45893: On 3/6 moved to east of Frederica, DE. On 3/7 located on the Elk River, Cecil County, MD. On 3/8 moved to north of Hopeland, Lancaster County, PA. On 4/12 moved to south of Lake Ontario in Oak Orchard, NY. On 4/18 moved west to Campden, Ontario where it remains to date.

55010: On 3/14 moved to Prime Hook NWR, DE. On 3/15 located on the Susquehanna River, west of Harrisburg, PA. On 3/18 located west of Gainesville, Wyoming County, NY where it remains to date.

55019: On 2/17 moved to the James River, Prince George County, VA. On 3/24 located adjacent to Rappahannock River, Caroline County, VA. On 3/28 moved adjacent to the Susquehanna River, north of Millersburg, PA. On 4/19 moved to west of Mount Forest, Ontario where it remains to date.

63004: On 3/17 moved to the Currituck Sound, NC where it remains.

63005: On 3/7 moved to Back Bay, VA. Signal lost on 3/15.

72791: On 3/3 moved to west of McSherrystown, Adams County, PA. On 3/10 moved to east of Gettysburg, PA. On 3/17 located west of Enon Valley, PA. On 4/9 moved to Dead Horse Bay, east of Green Bay Shores State Wildlife Area, WI. On 4/16 moved to Mississippi Headwaters State Forest, Beltrami County, MN where it remains to date.

72793: On 3/19 moved north to Sandusky Bay, Lake Erie, OH. On 4/4 moved to Walpole Island, Lake Saint Clair, Ontario. On 4/10 located on Saint Clair National Wildlife Area, Lake Saint Clair, Ontario where it remains to date.

72797: Confirmed mortality on Lake Mattamuskeet NWR, NC.

Doug L. Howell
Waterfowl Biologist
North Carolina Wildlife Resources Commission
132 Marine Drive
Edenton, NC 27932

Hen house occupancy rates:

•    In 2007, both southern Ontario and northwest Pennsylvania had an increase in hen house occupancy rates over 2006. In Pennsylvania a total of 56 (29%) hen houses were occupied including 29 wood duck nest and 27 mallard nest.

•    The overall occupancy rate for northwest Pennsylvania increased 40% from 40 occupied nests in 2006. There has also been a 69% increase in mallard nest and a 16% increase in wood duck nest from 2006.

•    In southern Ontario a total of 32 (17%) hen houses were occupied, including 24 mallards and 8 wood ducks. The overall occupancy rate for southern Ontario increased 78% from 18 occupied nests in 2006. There was also a 400% increase in mallard nest and a 50% decline in wood duck nest.

Figure 1: The number of occupied nesting structures in northwest Pennsylvania and southern Ontario in 2006 and 2007. This data represents raw counts of hen houses occupied of the available 200 in each region.

Nesting success rates:

• The nest success for mallards has decreased in both study sites. Pennsylvania declined from 93% in 2006 to 67% and southern Ontario declining from 100% in 2006 to 71%. Although there was a decline for mallards in both study sites, the success rate is likely well above ground nesting mallards in both regions.

• Wood ducks success also declined in Pennsylvania from 60% in 2006 to 40% in 2007 and southern Ontario increased from 58% to 75%. These declines are a result of several factors, including eggs freezing during early nesting attempts, abandonment from nest checks and capturing, water level rising and flooding nest, dump nesting of wood ducks, as well as two predated nest.

Figure 2: Nest success rates of wood ducks and mallards in northwest Pennsylvania and southern Ontario. Nest success is defined by the presence of at least one shell membrane.

Banding and web tagging:

•    During the 2006 nesting season, 15 mallard hens were banded in northwest Pennsylvania and southern Ontario to determine if successful hens are returning to the same hen house from year to year.

•    During 2007, 8 mallard hens (55%) were recaptured in the same or nearby hen houses indicating that hen philopatry to nesting structures is high.

•    Twenty five additional hens (consisting of 5 second year and 20 after second year) were also captured and banded in 2007 to examine homing rates next year.

•    During the 2007 nesting season, 34 mallard nests hatched producing 313 mallard duckling in both Pennsylvania and Ontario Combined. Of those, 251 ducklings were web tagged to study natal philopatry of offspring to nesting structures. As of 2007, there was no offspring philopatry from the 160 mallard web tagged in 2006.

Invertebrate and land use data:

• Currently, the 170 invertebrate samples, wetland size, and the land use data surrounding the 400 hen houses are being analyzed. Once this data has been collected, we will analyze it, along with other pond measurements to determine variables that influence site selection of mallards and wood ducks. The data will also be used to make a regional comparison of hen houses occupied by mallards to explain spatial variation in occupancy rates.

Seasons Greetings!!
December 2007

The Season is well underway and all of the HOGGS are hard at it. When things lighten up a bit, we will be getting more info added to the site for your viewing pleasure. If there is something you would like to see happen, just ask using the contacts page!!! Keep an eye out for Hogg-Wear coming Soon!!

Game Hogg members David Rearick and Erik Nilsson along with other waterfowlers in the area have teamed up to form the PA Waterfowl Heritage Society. The main goal behind the organization is to put money directly into the hands of local refuges and groups that can impact waterfowl for the Atlantic Flyway in PA. This event has many sponsors including David Denies Wingshooting, Sportsman's Warehouse, Avery, GHG, Zink, James Creek Outfitters and more. The ticket is $100.00, and there are only 100 tickets sold. There are four prizes, so essentially a 1 in 25 chance to win everything from an all expenses paid trip to Argentina to a Limited Edition Henry rifle to a Snow Goose Hunt. Check out the website for more information. (click on poster below)

The festival made for some great family fun with a kids fishing derby, calling contests, plenty of live animal exhibits – to include a live artic wolf and gators, logging sport demos, fly fishing classes, several vendors and exhibitors, plus some great fish fry and chicken BBQ.

The waterfowl calling contest was sponsored by Honker Bonker Guide Service, Zink Calls and Buck Gardner Calls. A meat calling format was used and three gentlemen proved their calling skills, placing in the top three for both the duck and the goose contests.