Search

American woodcock (Scolopax minor; woodcock) are monitored, in part, by counts of displaying male woodcock collected via the American Woodcock Singing Ground Survey (SGS), which suggests long‐term, range‐wide declines in woodcock populations. Data from the SGS have been used extensively to develop conservation plans, direct management actions, and understand causes of decline. To avoid bias, the SGS should be timed to avoid spring migration, and the distribution of survey routes should coincide with woodcock breeding distribution. Our objectives for this research were to evaluate SGS timing with the phenology of male woodcock migration, relate the spatial coverage of the SGS to male woodcock breeding distributions, and explore other sources of variation in woodcock migration timing. We marked 133 male woodcock captured throughout eastern North America with global positioning system (GPS) transmitters during 2019–2022, and compared the timing of their spring migration with the spatiotemporal stratification of the SGS. Most woodcock (74%) completed migration prior to the onset of the SGS. In the northernmost SGS zone, a greater percentage of males (34%) continued migration during the survey window; however, the influence of this mismatch is offset because SGS routes were run more frequently during the second half of the window. Young woodcock completing their first spring migration took 8.6 days longer to do so, on average, compared to adults, and so were more likely to migrate during the SGS window. We found little evidence that timing of migration varied among years. Existing SGS routes cover the majority of male woodcock post‐migratory breeding distribution, with 90% of male woodcock establishing final breeding sites within the spatial coverage of the SGS. Our results confirm the SGS includes some migrating males, with the proportion relative to resident breeding males increasing in more northern survey strata. Our data suggests these errors are unlikely to bias trend estimates at large scales (e.g., within woodcock management regions), but there may be potential for bias at more local scales (e.g., state or provincial population indices). [ABSTRACT FROM AUTHOR]

The American Woodcock Conservation Plan calls for halting and reversing declines of American woodcock (Scolopax minor) populations through creation and management of early successional forest (ESF). Counts of displaying male woodcock along routes of the American woodcock singing‐ground survey (SGS) are used to assess regional population status and trends, and there is a need to assess whether SGS routes represent the region. We assessed whether individual SGS routes (330‐m buffers) in the Boreal‐Hardwood and Prairie‐Hardwood Transitions of Minnesota, USA represented land covers within local landscapes, defined using simulated 10‐minute blocks, and whether the routes, in aggregate, represented land covers of our study region. Our land covers included non‐forest classes, age‐based ESF (≤20 years), and persisting classes for deciduous‐mixed and evergreen forests and woody wetlands. We found that the median value of mean absolute differences (MAD) between percentages for route buffer and block cover classes was 3.78 percentage points. Twenty‐two of 81 (27%) route buffers had MAD values ≥5 percentage points. Within Minnesota, more of these routes (19 of 22) occurred in the Boreal‐Hardwood Transition than in the Prairie‐Hardwood Transition. Relative to local landscapes, route buffers most frequently and strongly under‐represented open water, barren land, evergreen ESF, persisting woody wetlands, and woody wetland ESF and over‐represented developed land and grassland‐pasture. When we compared routes in aggregate to our study region, the magnitude of percentage point differences for individual covers did not exceed 5, except for open water. Given the relatively small differences we observed, we conclude that SGS routes well represent land covers within our study region. © 2018 The Wildlife Society. For most land cover classes, there were only small percentage point differences between singing‐ground survey routes and Minnesota, USA, suggesting the routes representatively sample American woodcock habitat component classes in the state. These results may not be geographically transferable and thus similar route assessments using consistent methods are needed for areas throughout the region covered by the singing‐ground survey. [ABSTRACT FROM AUTHOR]