Activity 1. Quantify viability of corridors using temporal sampling: past, present, future. As large-scale wind patterns change, the viability of flyways in the Pacific hemisphere is likely to change. This project will evaluate the tail/headwind components for flight routes from Alaska to sites in the South Pacific (documented godwit and curlew flight tracks) by sampling 50-year timeslices to determine whether the present climatology is more or less favorable than the past (paleoclimate) periods or the projected future (late 21st century). The project will determine whether other flight corridors may have been more advantageous in the past or future than during the present period. Activity 2. Assessment of optimization of timing of departures. Available data in the migration tracking archive (Movebank) identify the dates of departure of birds during the past several years. A fundamental question is: do birds optimize their departure dates with respect to weather patterns? By examining the head/tailwind index for alternative departure dates, the project may determine whether optimization has occurred. Activity 3. Teleconnection patterns relevant to variability of flight optimization. Departure of godwits and curlews appears to be keyed to the west to east passage of low pressure centers across the Aleutians. Are these passages correlated with broader (remote) circulation features conducive to favorable flight conditions farther en route? Alternatively, if flight tracks are composed of favorable and unfavorable head/tailwind indices, how are these two categories of flight conditions manifested at the birds’ points of departure in Alaska? By examining teleconnections, the project will attempt to shed light on the circulation patterns over the broader Pacific domain that are most critical to migratory success via favorable winds en route with special emphasis on the Aleutian Low.
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