The Winter Bird Population Survey is patterned after the Winter Bird Population Study initiated by the National Audubon Society in 1948. The purpose of the WBP Studies is to examine the population dynamics of wintering birds. Numbers of birds from the Studies can be used as an index of abundance and compared to other years and other study plots. The WBP Study is published annually in the Journal of Field Ornithology.

There are certain restrictions in participating in the WBP Study. For a woodland area like the Environmental Study Area at UM-D, the study plot must be a minimum of 10 hectares, square or rectangular, of homo genous habitat surrounded by the same or similar habitat. The linear nature of the Environmental Study Area, which is situated along the Rouge River floodplain, precluded the establishment of an official WBP Study plot. Instead, we have adopted some of the WBP Study protocol and incorporated it into our WBP Survey.

Like the Study, our Survey takes place between 20 December and 20 February. The area is visited a minimum of eight times, and the whole area is covered, if possible, on each visit. Each visit is of approximately the same duration (1.5 to 4 hours) during the same time of day (before noon). During each visit, starting time, weather conditions, and incidental observations are recorded. Each bird encountered in the study area is counted, but unlike the WBP Study, the birds are not mapped. Data is summarized according to WBP Study format. The first value following each species is the average number of individuals encountered per visit (rounded to the nearest tenth) and the value in parenthesis is the number of visits during which a species was encountered (frequency of occurrence). Birds are listed in order of abundance.

All WBPS results posted here

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