OBBA

Migration Banding

General Overview of all stations

The migration banding with which we are familiar involves application of relatively large numbers of bands, with very few recaptures or recoveries in subsequent years. These studies typically are not designed to yield data that can be used to estimate survival probabilities or other demographic parameters. Instead, the data are often used to provide information on the timing of migration, and, in some cases requiring very restrictive assumptions, to index abundance. In these two cases recaptures are used simply to identify individuals that have already been encountered and counted, and therefore maintenance of recapture data by the Bird Banding Laboratory is not required.

In some special sampling situations, capture-recapture/resighting at migration stopover sites can provide data with which (1) stopover times, and even (2) numbers of birds passing through the area, can be estimated. These estimates permit identification of important stopover sites and their characteristics. Such analyses require data at frequent sampling periods (sampling every day or every few days throughout the migration period). The potential for meta-analyses of this sort across many banding stations, and hence the potential value of central storage at BBL, is increased only if all stations are using a standardized methodology (and greater still if other standard ancillary data are collected and centrally stored). Without standard methods, the data are not conducive to standardized storage in that records will be tailored to a specific study design. Without standardization these studies can be regarded as local project-oriented studies.