Table 1 Candidate models for discrete choice analysis
From: Environmental drivers of autumn migration departure decisions in midcontinental mallards
Model | Covariates | Notes |
|---|---|---|
Null model | Choice set ID | Statistical null model |
Temperature | Temp | Air temperature at 2 m (ºc) |
Snow cover | Snow | Depth of snow cover (m) |
Pressure difference | Press diff | Difference in barometric pressure to next record (Pa) |
Precipitation | Precip | Accumulated water (rain, snow, freezing rain, hail) (kg/m2) |
Cloud cover | Cloud | Total cloud cover (%) |
Tailwind speed | Tail | Speed of wind with heading within ± 60º of mean relocation direction (m/s) |
Headwind speed | Head | Speed of wind with heading greater/smaller than ± 60º of mean relocation direction (m/s) |
Frost days | Frost days | Number of sequential days of temperature < 0ºc experienced by mallard at this location |
Snow days | Snow days | Number of sequential days of snow depth ≥ 2.54 cm (1 inch) experienced by mallard at this location |
Ice cover | Ice cover | Presence (y/n) of ice cover ≥ 1 cm on shallow water bodies |
Full model | Temp + snow + press diff + precip + cloud + tail + head + frost days + snow days + ice cover | All covariates (n = 10) |
Daily scale | Temp + snow + press diff + precip + cloud + tail + head | Shorter-term (daily) conditions |
Multi-day scale | Frost days + snow days + ice cover | Longer-term (multi-day) conditions calculated as cumulative parameters |
Winter conditions | Temp + snow + frost days + snow days + ice cover | Covariates specific to winter conditions (low temperature, snow, ice) |