Geology topics

Ronald E. Reynolds

Publications and source records attributed to Ronald E. Reynolds.

6 recordsLinked to original sources

USGS2018

Density and success of upland duck nests in native‐ and tame‐seeded conservation fields

The Conservation Reserve Program (CRP) generates substantial benefits to continental duck populations by providing grassland nesting habitat in rested cropland. Seeding mixes of CRP grasslands vary among numerous conservation practices, but one contrast of interest in the Prairie Pothole Region is the use of introduced, or “tame” versus native grass. Although the benefits of CRP to duck populations are well‐known, relative values of these planting practices to nesting ducks have received little attention. Understanding differences in benefits to ducks due to planting practices would aid in prioritizing and selecting management practices for CRP and other restoration activities. We evaluated nest survival and density of ducks nesting in tame‐ and native‐seeded CRP fields in 36 study areas in the Prairie Pothole Region of North Dakota and South Dakota, USA, during 2002–2003. We searched for duck nests in 209 fields totaling 5,386 ha and found 2,941 nests. We found no support for differences in nest survival for any upland‐nesting duck species between fields seeded to tame versus native grass based on a design and analyses that accounted for spatial and temporal variation. Additionally, nest densities, adjusted for nest survival rates, of all duck species were similar between tame‐seeded and native‐seeded fields. We conclude that benefits to nesting ducks from native‐grass seeding practices of CRP were similar to those of tame‐grass seeding practices. Although there may be other reasons to plant native seed mixes when establishing CRP tracts (e.g., native pollinators or insects, other wildlife species, etc.), our study suggests that duck nesting density and nest survival are not among those reasons.

North Dakota, South Dakota↗

USGS2006

Determinants of mallard and gadwall nesting on constructed islands in North Dakota

Constructed islands with adequate nesting cover provide secure nesting sites for ducks because islands restrict access by mammalian predators. These islands are costly to construct and should be placed in areas that ensure the greatest use by nesting ducks. We studied mallard (Anas platyrhynchos) and gadwall (A. strepera) nesting on constructed islands in North Dakota in 1996 (n = 20) and 1997 (n = 22) to evaluate factors—particularly amount of perennial grass cover in the surrounding landscape and density of breeding pairs—that possibly influence numbers of initiated nests. We also examined effects of island characteristics, such as island vegetation, on numbers of nests. Numbers of mallard and gadwall nests on islands were negatively related to amounts of perennial grass cover in the surrounding uplands. Numbers of mallard nests were positively related to percentages of tall dense cover on islands. We found no effects of breeding-pair density on numbers of nests initiated by either species, possibly because breeding pairs were abundant on all study sites. Percent shrub cover on islands was a better predictor of island use than was percent tall dense cover. Island use by these species increased with island age and distance from mainland shore. Amounts of perennial cover in landscapes should be primary considerations in determining where to build islands. Our data suggest that use of islands by nesting mallards and gadwalls is greatest in landscapes with little perennial grass cover (i.e., high amounts of cropland). Other researchers documented a positive relation between nest success in upland covers and amount of perennial grass cover in the landscape. Therefore, islands constructed in landscapes with little perennial cover should provide greater gains in duck recruitment rates than islands constructed in landscapes with greater amounts of perennial grass cover.

Journal of Wildlife Management↗

USGS2001

Impact of the Conservation Reserve Program on duck recruitment in the U.S. Prairie Pothole Region

The U.S. Department of Agriculture (USDA)'s Conservation Reserve Program (CRP) resulted in the conversion of about 1.9 million ha of cropland to perennial grass cover in the Prairie Pothole Region of North Dakota, South Dakota, and northeastern Montana by 1992. Many wildlife managers believed this cover would provide benefits to wildlife, including upland nesting ducks. During 1992-1995, we evaluated success of 5 duck species nesting in CRP fields and nearby Waterfowl Production Areas (WPA) throughout the region. We examined relationships between daily survival rates (DSR) of duck nests in CRP cover and landscape-level habitat and population parameters. We computed DSR of duck nests in other major cover types in our study area from data collected during 1980-1984 (pre-CRP) and 1990-1994 (CRP) periods. We then applied recruitment models to estimate duck production in our study area during peak CRP years (1992-1997) and compared these results with those that simulated the scenario in which cropland was in place of CRP cover (i.e., the CRP had not occurred). DSR were higher in all habitats combined during the CRP period compared to the pre-CRP period. Regressions of DSR in CRP cover on the percent of each study plot in perennial cover and geographic location were significant (P < 0.01) for 4 of 5 duck (Anas spp.) species. Estimated nest success and recruitment rates for the 5 species combined during 1992-1997 were 46% and 30% higher, respectively, with CRP cover on the landscape compared to a scenario where we simulated cropland in place of CRP. Our model estimated an additional 12.4 million recruits from our study area to the fall flight as a consequence of the CRP during 1992-1997. Our results document benefits to 5 duck species in the northern plains associated with a farm program that provided financial incentives to landowners for planting undisturbed grass cover as an alternative to annual crops.

Journal of Wildlife Management↗

USGS1995

Spring-summer survival rates of yearling versus adult mallard females

Knowledge of the timing, magnitude, and cause of mortality in wildlife populations is imperative for developing management strategies that protect or improve the status of these populations. Age- and sex-specific population parameter estimates provide the most useful information for this purpose. Numerous studies have provided information about survival rates in mallards ( Anas platyrhynchos ), but little is known about age-related differences in female survival during the breeding period. We examined band-recovery data for female mallards banded in southern portions of Alberta, Saskatchewan, and Manitoba during spring and summer 1981-85. We used band-recovery models to test the hypothesis that yearling females would exhibit higher survival compared with that of older females during spring-summer. There was evidence ( P = 0.08) that spring-summer survival rates of yearling females (0.728) were higher than that of older females (0.574). These findings support the hypothesis that age-specific differences in nesting behavior (e.g., later nest initiation and fewer nesting attempts by yearlings) influence losses to predators and are responsible for the difference in spring-summer survival. Management treatments that increase nest success, and consequently reduce the need for prolonged nesting, will increase mallard survival during spring-summer.

Alberta, Manitoba, Saskatchewan↗

USGS1995

Geographic variation in band reporting rates for mallards based on reward banding

We conducted a reward band study on mallards ( Anas platyrhynchos ) to estimate and test hypotheses about sources of variation in band reporting rate. We banded 25,398 mallards with standard and 100 reward bands (3 mallards banded with standard bands for every reward-banded mallard) during preseason (Jul-Sep), 1988. We used a series of multinomial models to model the resulting 2,776 band recoveries from 1988 to 1991. Estimates of reporting rate for males shot in 10 harvest areas ranged from 0.29 to 0.46 and averaged 0.38 (SE = 0.020). We found evidence ( P < 0.01) of geographic variation in reporting rates, but not of smooth latitudinal or longitudinal gradients. There was evidence ( P = 0.07) of lower reporting rates for females than males, especially in prairie Canada and the Central Flyway. Except for young males in the northern Atlantic Flyway, estimated harvest rates were lower than historical estimates, as expected from recent restrictive hunting regulations. Patterns of geographic and agesex variation in harvest rates were similar to those obtained using historical band-recovery data.

Journal of Wildlife Management↗

USGS1991

Band reporting rates for mallards with reward bands of different dollar values

Adult male mallards ( Anas platyrhynchos ) were banded in summer 1987 with reward bands of different dollar values (0-$400) to determine the lowest dollar value that would yield a reporting rate approaching 1.0. During the 1987-88 and 1988-89 hunting seasons, rewards of between 50 and $100 were required to yield a reporting rate near 1.0. We estimated reporting rate of standard bands to be 0.32. Reward bands with 5 and $10 values produced reporting rates that were 1.5-2.0 times as large as those of standard bands. We developed a linear-logistic model to predict reporting rate as a function of the dollar value of reward bands.

Manitoba, Saskatchewan↗