Early spring waterfowl surveys present mixed picture
Floods not expected to have significant impact on breeding success
MADISON – Variable spring habitat conditions observed in the United States and Canada present a mixed picture for the fall 2008 waterfowl seasons in Wisconsin, according to the state wildlife officials. Preliminary information shows areas ranging from very good wetland conditions to very dry. Biologists will have a better understanding of what impact these conditions had on actual breeding waterfowl numbers when they finish compiling and analyzing spring waterfowl breeding surveys.
“We’ve completed the annual Wisconsin Breeding Waterfowl Survey, which is very important since a large proportion of the ducks harvested in Wisconsin are hatched in Wisconsin,” said Kent Van Horn, Department of Natural Resources migratory waterfowl biologist.
A cooperative survey of Canada geese, the Mississippi Valley Population (MVP) Breeding Survey, organized by the Ontario Ministry of Natural Resources was delayed this year because of late winter conditions on the nesting grounds.
The final piece is the U.S. Fish and Wildlife Service breeding waterfowl survey for the northern U.S., Canada and Alaska. That information is expected in the next few weeks and will form the framework for the 2008 fall seasons.
Ducks
Waterfowl breeding areas in Canada this spring had poor to good conditions. Waterfowl breeding is expected to be mostly poor to fair across much of prairie Canada but better in other areas. Moisture conditions and precipitation in U.S. prairies were mixed with most of North Dakota in very dry conditions and South Dakota with poor to good conditions. Overall breeding duck numbers were similar in North Dakota compared to 2007 but are expected to have reduced breeding success due to dry conditions.
In Wisconsin, high winter snowfall helped to create wet conditions across most of the state. Spring precipitation was above average from March through May for all of Wisconsin.
Major flooding in early to mid June may have had an impact on some duck nesting success, but many duck nests would have already hatched by this time, according to Van Horn. Further, species such as mallards commonly re-nest after a nest is destroyed. While some duck nests may have been flooded, habitat for duck broods that did hatch would be improved by flooding. The overall impact of the flooding on breeding ducks in Wisconsin is not expected to significantly reduce survival.
The four most abundant ducks in Wisconsin’s fall hunting harvest are mallards, wood ducks, green-winged teal and blue-winged teal.
The 2008 total state breeding duck population estimate of 626,924 (plus or minus 77,236) is up 33 percent from 2007 and 45 percent above the long-term mean. This number is a little larger than the average for the last 10 years as was expected given the improved wetland conditions in 2008. Overall breeding duck survey results indicate a healthy, relatively stable population of breeding ducks in Wisconsin experiencing normal annual fluctuations. This is a positive indication of hunting regulations and habitat management/protection.
“These are population estimates – not exact counts – so changes of near 20 percent up or down in the estimates each year may not reflect any real change in the actual population,” Van Horn said.
The 2008 Wisconsin breeding population estimate for mallards of 188,429 (plus or minus 23,850) is similar to last year’s estimate of 210,219 given the level of precision in the survey. The 2007 estimate is 4 percent above the long-term mean (35 years).
The 2008 blue-winged teal breeding population estimate of 179,549 (plus or minus 38,772) is up 45 percent from 2007 but statistically similar between these 2 years given the high variation and 58 percent above the long term mean that excludes the migrant years of 1981, 2004 and 2005. The 2008 estimate is the third year of population estimates over 100,000 in recent years after several years of estimates under 100,000. Additional years of data will be needed to reveal whether the long term blue-winged teal population decline has halted.
“We continue to have a concern for sustainable breeding habitat for both mallards and breeding blue-winged teal in Wisconsin,” Van Horn said. “While our conservation efforts of the past have been successful, the threats to decreased grassland nesting habitat for blue-winged teal and mallards have increased with changes to the federal farm bill and high corn prices which are expected to result in more corn in areas that had been grasslands set aside in the Conservation Reserve Program.
The 2008 breeding population estimate for wood ducks of 126,440 (plus or minus 24,157) is up from 2007 as expected. During 2007, Wisconsin was experiencing drought conditions in key wood duck breeding areas and the 2007 count was very low. The 2008 estimate for wood ducks returned to a level similar to the last 10 year average. Current trend analysis for wood ducks in Wisconsin suggests that the long term increase in the breeding population is leveling off.
Canada Geese
“There are two different populations of Canada geese that represent most of the geese in Wisconsin during the regular fall hunting season and our harvest is about 50 percent from each of these populations during the regular hunting seasons,” Van Horn said.
One population, called resident giant Canada geese, nests in Wisconsin. The 2008 breeding population estimate of 116,715 for this population is down 7 percent from 2007 but 48 percent above the long-term (22-year) mean. While the long term trend for Wisconsin’s resident Canada geese has increased, recent survey years suggest that this increase may have leveled off near 120,000.
The second Canada goose population is the Mississippi Valley Population, which is made up of slightly smaller birds that nest along the coast of Hudson Bay in northern Ontario and migrate through Wisconsin and other Midwestern states. Survey information on this breeding population is not yet available but initial reports suggest a decreased breeding effort from 2007 which was a very good year. The nesting grounds in northern Ontario experienced a very late winter, difficult nesting conditions and delayed nesting. These factors normally result in decreased production.
FOR MORE INFORMATION CONTACT: Kent Van Horn - (608) 266-8841
