Characterizing bird migration phenology using data from standardized monitoring at bird observatories

摘要: Long-term data from standardized monitoring programmes at bird observatories are becoming increasingly available. These frequently used for detecting changes in the timing of migration that may relate to recent climate change. We present an overview problematic issues analysis these data, and review approaches methods characterizing phenology its change over time. Methods illustrated briefly compared using autumn on garden warbler Sylvia borin a mist-netting programme Lista observatory, southern Norway. Bird is usually characterized rather coarsely small number sample statistics such as mean, median selected quantiles. 2 alternative approaches. Smoothing describe within-season pattern arbitrary level detail, while fitting parametric seasonal distribution curve offers coarse description relatively robust sampling effects. Various analyzing linear trends reviewed discussed. Exploratory studies long-term gathered can yield more detailed insight into phenomenon how phenologies climate. Methodological advances needed, particularly order better characterize shape phenological distributions separate between effects 'true' phenology.