Optimal departure decisions decisions of songbirds from an experimental stopover site and the significance of weather

摘要

Recent models have worked worked with the assumption that birds try to minimize either time, energy or predation risk during migration, or some combination of these. The few empirical studies available have suggested that time minimization may be the most common strategy. One way of distinguishing between strategies is to study the departure decisions of migrating birds. We supplied migrating European robins, Erithacus rubecula, with food ad libitum in the field and monitored their changes in body mass prior to Departure.