Bird Banding Laboratory

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Bird Banding Recapture Database Survey Results

In July, 2000, BBL conducted a survey of banders to locate potentially available databases as well as to assess bander attitudes towards the development of a recapture database. Of the more than 500 banders (25% response rate) who returned the survey form: 94% indicated that they recorded recapture data; 71% collected recapture data for project specific purposes; 55% recaptured more than 20 adults of a single species per year; and 28% recorded recaptures as part of large-scale projects such as MAPS (Monitoring Avian Productivity and Survivorship).

Many banders indicated that they record every recapture (Fig 1.). Many reported having long-term data sets, with 156 data sets extending greater than 15 years (Fig 2.), and containing thousands of records (Fig. 3). However, only 26% of these data sets were being actively analyzed using contemporary mark-recapture models.

Asked if they were willing to contribute their data to the recapture database, 80% indicated yes, 9% said no, and 12% expressed proprietary concerns. Twenty-three % of the respondents would like to be able to consult an analytical specialist, 69% indicated a willingness to contribute to future, collaborative studies involving recapture data. Fourteen % of respondents were aware of recapture datasets in danger of being lost.

In summary, large numbers of banders collect thousands of recapture data, some of which will be lost if not permanently archived. Banders are generally willing to contribute their data, and are supportive of developments concerning recapture data.

Chart, Frequency of Recaptures

Figure 1.  The frequency with which banders record recapture data.

Chart, Recapture projects

Figure 2.  Number of data sets with associated time series over which the data have been collected.

Chart, number of recaptures

Figure 3. The number of records associated with each data set.