Common snipe habitat, surveys and evaluation of the breeding bird survey.

摘要

Common snipe numbers in North America are unknown, in part, because no survey technique to monitor their numbers has been developed. I developed and evaluated three indices to abundance (point count, call count, and winnow count) to monitor snipe trends. I identified six factors (season, time of day, lunar cycle, solar radiation, wind speed, and temperature) that effect snipe behavior and considered their effects when evaluating the indices. From my evaluation, I identified the point count to be the best of the three.I identified four habitat characteristics [soil moisture, water depth, distance to nearest shrub cover, presence and dominance of herbaceous plants (sedges)] that were important for snipe and evaluated the BBS for snipe, since doubts about the use of this technique exist. My results suggest the BBS is not a useful technique for monitoring snipe trends.I evaluated four labor intensive techniques (territorial/spot mapping, flush counts, tape playback territorial mapping and nest searches) to estimate numbers of snipe or their territories. Territorial/spot mapping most accurately represented the number of territories present, followed by flush counts, tape playback territorial mapping, and nest searches in that order.