Migration Info This species' annual migration is the longest of any flycatcher that breeds in North America. The Olive-sided's winter habitat is primarily in the highlands of Panama and the northern Andes. Peak winter abundance is in the Andean portion of Colombia. Migrants generally bypass the Yucatan (although there are a few trans-Gulf migrants each year) and move through North America via the western forests. Olive-sided Flycatchers leave their winter territories in late March and are among the later arrivals in the southern states. The reason for this late arrival on breeding territories is probably this species' dependence on large flying insects, which are less numerous before the warmer spring weather.