Less water, fewer ducks
7/20/2008The relationship between success in annual waterfowl production and the relative availability of water is very well understood, so it should be no surprise to learn that duck numbers continent-wide this year are down.
That is because the amount of water present in portions of the Canadian prairies and parklands and in the north central United States so far this year is considerably lower than a year ago.
That's the executive summary of the duck picture, based on the recently released U.S. Fish & Wildlife Service annual report on mid-continent breeding ducks and habitats. The report, which may be tweaked with supplemental results later, is based on surveys conducted in May and early June across the key breeding grounds.
Total populations of 10 key index-species of ducks were estimated at 37.3 million breeders, down nine percent from the 2007 estimate of 41.2 million. Even with the decline, however, the index for 2008 remains 11 percent over the 1955-2007 long-term average.
"The decline in breeding habitat conditions is consistent with what Ducks Unlimited's field biologists have reported across much of the U.S. and Canadian breeding grounds this year," said Dale Humburg, the organization's top biologist. "While late rains may have improved habitat for late-nesting species, and re-nesting and brooding, poor production likely will occur over key production areas, particularly the grasslands of the U.S. and Canada."
Total pond counts showed 4.4 million ponds, down a whopping 37 percent from 2007 and 10 percent below the long-term average. That led to habitat conditions DU called good news-bad news.
Drought in many parts of the prairie survey areas, including the pothole region, contrasted sharply with record snow and rain in the eastern portions of the survey area. Since 1990 surveys have been conducted in eastern North America in addition to the traditional central-western areas.
The whole survey is all-important in leading to setting of annual waterfowl hunting regulations, tailored by each state and province with a federal framework constructed by the four Flyway Councils and USF&WS regulations committee. Ohio and Michigan seasons should be established by late August.
Among specific index species, the all-important mallard population was down by seven percent from 2007 at 7.7 million on traditional survey areas, compared to 8.3 million a year ago.
This year's number meets the long-term average and the decline is consistent with a late spring and fewer ponds, according to Humburg.
Positive developments were seen among redheads, green-winged teal and scaup. For the second year redheads remained about a million birds, 66 percent above the long-term, and greenwings remained similar to 2007 numbers at nearly three million, about 57 percent above long-term. Scaup, or bluebills, appeared to have stabilized at levels similar to the last eight years at 3.7 million. But the species remains 27 percent below long-term average.
Six of the 10 index ducks showed no significant changes, but the other four all declined appreciably, DU noted. The declines included canvasbacks, down 44 per cent from 2007; northern pintails, down 22 percent; gadwall, down 19 percent, and northern shovelers, or spoonbills, down 23 percent.
Canvasback were 14 percent below their long-term average at 489,000 birds, pintails 36 percent below long-term at 2.6 million. But despite declines since 2007 among gadwalls and shovelers, both species remained 56 percent above long-term average.
American wigeon remained at 2.5 million, similar both to 2007 and the long term. Blue-winged teal also were similar to 2007 and 45 percent above long term.
DU's Humburg said that pintails and scaup, which continue well below long-term averages, remain a special concern. "Habitat changes are believed to be the primary causes of decline for both these species," he added, noting that research programs targeted at finding sound, long-term conservation solutions are on-going.
Through all of the foregoing, waterfowl biologists underscore the importance of conserving grasslands and wetlands. Droughts are temporary; when rains and snow return, prairie wetlands again can teem with breeding ducks and other wildlife - if the habitat still is intact.
Biologists also have learned the importance of conserving more stable wetlands in the
boreal forests, which are much less susceptible to drought. "Habitat is the core factor driving healthy duck populations and size of the fall flight," Humburg said. "Habitat also is a key for waterfowl in migration and for hunters. This year, spring and early summer flooding in the Midwest and South, drought in the prairies, and extremely dry conditions in parts of the West Coast could affect migration and hunting habitat."
Here in Ohio, weather patterns during migration and the progress of crop harvest are annually important factors as well in hunting prospects. Ducks need reasons to drop in instead of flying over, and nasty weather and post-harvest crop residue supply them.
Tuesday: Ohio sets early migratory bird seasons, and seeks feedback from duck and goose hunters on some new proposals.