Habitat selection and activities of dabbling ducks during non‐breeding periods

Abstract

Western Tennessee is an important region for waterfowl during non‐breeding periods, supporting >40% of the Mississippi Flyway population of American black ducks (Anas rubripes). Understanding habitat selection and activities of waterfowl during the non‐breeding period is important for directed habitat management on national wildlife refuges and in other wetlands important in meeting regional waterfowl conservation objectives. During November–February 2011–2013, we investigated diurnal habitat selection and activities of dabbling ducks (Anatini) among 5 common wetland types relative to emergent cover, water depth, and energetic carrying capacity (i.e., duck energy days [DEDs]) in western Tennessee, USA. We observed waterfowl daily and sampled food resources monthly at Tennessee and Cross Creeks National Wildlife Refuges. Mallard (Anas platyrhynchos), gadwall (A. strepera), northern pintail (A. acuta), and American green‐winged teal (A. carolinensis) selected moist‐soil wetlands over wooded, aquatic bed, and open water wetland types. Gadwall also selected deeper wetlands containing submersed aquatic vegetation. Foraging was the dominant activity of all dabbling ducks in mudflats and moist‐soil wetlands, and it was also dominant in wooded wetlands for green‐winged teal and gadwall. Deep, open water was avoided by dabbling ducks. Selection of wetland types was negatively correlated with increasing water depth and positively correlated with increasing emergent cover and DEDs. Shallowly flooded moist‐soil and wooded wetlands provide high‐energy foods and dense emergent cover, and are important to a diversity of dabbling ducks during winter. © 2017 The Wildlife Society.

Energetic implications of floodplain wetland restoration strategies for waterfowl

“…SAV also provided habitat for aquatic macroinvertebrates, which accounted for 25 kg/ha of food in aquatic bed communities at Emiquon Preserve. In contrast, Hagy and Kaminski () found 0.9–1.8 kg/ha of aquatic macroinvertebrates in actively managed moist‐soil wetlands across the lower Mississippi Alluvial Valley and Osborn et al () found 10.1–20.8 kg/ha during November–February in moist‐soil wetlands in Tennessee. Aquatic bed communities provide the greatest amount of food energy for waterfowl in semipermanent emergent marshes, but the interspersion of cover types is an important predictor of waterbird use across the annual cycle (Kaminski & Prince ; Smith et al ).…”

“…Consequently, we increased production estimates using a standard correction factor (1.72) developed from seed production estimates and SPI values from Stafford et al (). Other cover types, which included mudflat, bare soil, and open water, contained no or very little vegetation and therefore were assumed to contain an insignificant amount of seeds and tubers available to waterfowl (Osborn et al ). Osborn et al () indicated that rapid assessment models used to predict seed production of moist‐soil plants were temporally and spatially robust and accounted for >90% of biomass at sample locations; thus, we assumed our visual assessment models provided reasonable estimates of food density for waterfowl.…”

The Influence of Water Depth on Energy Availability for Ducks

“…Most habitat conservation planning, acquisition, and management to increase local duck populations during the nonbreeding season focus on providing abundant, energy‐rich food (Playa Lakes Joint Venture [PLJV] Waterfowl Team , Soulliere et al ). Food availability can affect local duck abundance and distribution by attracting ducks to food‐rich areas (Brasher , O'Shaughnessy , Hagy et al , Osborn et al ) and influencing stopover duration during migration (O'Neal et al ). Food availability can also affect how ducks use vigilance behavior to govern predation risk (Brown and Kotler , Behney ).…”

“…Sampling over multiple occasions facilitated estimating food depletion during each period, which may provide an index to intensity of duck use of sites (Hagy and Kaminski ). Based on the attractiveness of moist‐soil wetlands to ducks because of their structure and high food production (Kross et al , Osborn et al ), I predicted that actively managed emergent wetlands (i.e., moist‐soil impoundments) would produce the most energy and exhibit the greatest amount of energy depletion throughout the nonbreeding period. My second objective was to estimate the average percentage of a wetland that was shallow enough to facilitate feeding by dabbling ducks, which represents a major component of how much food is actually available to be consumed.…”

Wetland Characteristics and Wintering Passerellidae Occupancy on Agricultural Conservation Easement Program Wetlands in West Virginia

“…Additionally, the presence of shrubs or dense herbaceous material can provide wildlife shelter. Dabbling duck use of wetlands was positively correlated with dense emergent vegetation (Osborn et al 2017), as it provides thermal cover in the winter (Jorde et al 1984) and possible shielding from predation (Euliss and Harris 1987) in addition to acting as a food resource in the form of seeds and tubers.…”