Waterfowl Nesting and Vegetation Data from Habitat Management Treatments at Grizzly Island Wildlife Area, Suisun Marsh, California, 2008-2013

These datasets provide nest-level and vegetation data collected during a study evaluating the response of upland-nesting waterfowl to habitat management treatments at Grizzly Island Wildlife Area, Suisun Marsh, California, USA, from 2008 to 2013. The study used a Before-After-Control-Impact (BACI) design to assess the effects of upland vegetation treatments (dense nesting cover, native plantings, and cereal grain) on waterfowl nesting ecology.

The dataset nest_data_share.csv contains nest-level observations used to evaluate nest survival, nest initiation timing, clutch size, and hatching success. Records include nest identifiers, year, site, treatment type, pre- or post-treatment designation, species, visit dates, estimated nest age, exposure days, survival outcomes, initiation date (Julian day), clutch size, and calculated hatching success for unmanipulated nests. Nest records were filtered to exclude nests influenced by experimental manipulation, monitoring devices, or other factors that could bias demographic estimates.

Vegetation characteristics associated with nest sites were quantified using measurements of lateral visual obstruction, canopy cover, and Robel pole height. These data were collected at nest locations and paired sampling points and are included within the nest dataset.

The dataset veg_data_transect_share.csv contains transect-based vegetation measurements collected independently of nest locations to characterize field-level habitat conditions across treatments and years. Variables include year, treatment type, site, pre- or post-treatment designation, day of year, and vegetation structure metrics (lateral density, canopy density, and Robel height).

Together, these datasets support analyses of relationships between habitat management, vegetation structure, and waterfowl nesting performance in a highly modified agricultural wetland landscape. Similar habitat factors, such as vegetation structure, landscape composition, and agricultural practices, are known to strongly influence waterfowl nesting success and productivity in North American breeding systems.