From the Field:

Large-scale perspective: Necessity to maintain duck populations

Nesting Success Research 

June 23rd, 2009

As we near the end of June, wetland conditions continue to be excellent with a very strong nesting effort underway across the Dakotas. Fortunately, we’ve received large doses of rain across the prairies of the Dakotas which will help to sustain the excellent wetland conditions we’ve enjoyed this spring. Bismarck received over 8 inches of rain last week in a 24 hour period. Most of the active nests include gadwall, blue-winged teal, northern shovelers and mallards. However, as testament to the excellent wetland conditions, many pintails are still actively renesting which is unusual given their usual tepid propensity to renest. To date, our crews have located 1635 nests on our study areas, and the fate of many of these nests will be determined over the next few weeks. Current wetland conditions should facilitate very good survival of the ducklings that continue to hatch from nests across our study sites as the number of broods across the landscape continues to build. We have had a total of 306 nests hatch to date across all of our research sites with the best sites being Lostwood site 8 (39 hatched nests), Woodworth site 27 (24 hatched nests) and Goebel site 41 (46 hatched nests). Overall, it seems things are shaping up for very good duck production across our study areas. We will see how well the remaining active nests fare through the remainder of the nesting season this year. This week in From the Field, we will discuss the large spatial scales over which ducks operate throughout the summer and early fall.

With nesting activity winding down, it’s interesting to think about what different components of the population are doing and where they are right now. Many drakes that were paired with hens across our study sites have gone on molt migrations that may have taken then as far as northern Canada while a few remain to seek out renesting females. They seek large marshes that provide both the dense emergent cover and food that they’ll need to spend several weeks grounded as they go flightless to re-grow flight feathers. Obviously, nesting hens still attempting to hatch a nest remain on our study sites. However, some females that lost earlier nests may have either migrated some distance to try their luck with a renest or may have headed north for a molt migration of their own. Females with young broods are likely still in the area where they nested but some of the earliest hatched broods will soon be flying and much more mobile. The period between fledging and fall migration is probably the portion of the duck life-cycle that we know the least about. We suspect that some of these birds may move hundreds of miles to take advantage of agricultural foods once harvest of those begins. As a result, an area can be literally crawling with broods during June and July, as much of the Coteau currently is, only to be nearly devoid of ducks come August as flighted young birds move to more agriculturally dominated areas to take advantage of energy rich waste grain. Thus, as the nesting season nears completion, birds that originally started the season on our study sites could soon be scattered from Northern Canada to western Minnesota prior to the onset of fall migration. This fact illustrates why Ducks Unlimited must have broad-scale conservation programs to effectively conserve duck populations. Even within the breeding areas, maintaining the large landscapes dominated by grassland from southern South Dakota to northern Saskatchewan remains a priority for DU and requires diverse financial support from across the continent to achieve success.

We hope you will continue to follow along with our work as we gather the final pieces of information from the 2009 nesting season. The next couple of weeks will give us a more complete picture of how production was across our sites. Check back in a couple of weeks to see the happenings on the prairies.