DEVELOPMENT OF MATCHED (MIGRATORY ANALYTICAL TIME CHANGE EASY DETECTION) METHOD FOR SATELLITE-TRACKED MIGRATORY BIRDS

Abstract

Satellite tracking technology has been used to reveal the migration patterns and flyways of migratory birds. In general, bird migration can be classified according to migration status. These statuses include the wintering period, spring migration, breeding period, and autumn migration. To determine the migration status, periods of these statuses should be individually determined, but there is no objective method to define 'a threshold date' for when an individual bird changes its status. The research objective is to develop an effective and objective method to determine threshold dates of migration status based on satellite-tracked data. The developed method was named the “MATCHED (Migratory Analytical Time Change Easy Detection) method”. In order to demonstrate the method, data acquired from satellite-tracked Tundra Swans were used. MATCHED method is composed by six steps: 1) dataset preparation, 2) time frame creation, 3) automatic identification, 4) visualization of change points, 5) interpretation, and 6) manual correction. Accuracy was tested. In general, MATCHED method was proved powerful to identify the change points between migration status as well as stopovers. Nevertheless, identifying “exact” threshold dates is still challenging. Limitation and application of this method was discussed.