Contrasting extreme long‐distance migration patterns in bar‐tailed godwitsLimosa lapponica

Abstract

Migrating birds make the longest non‐stop endurance flights in the animal kingdom. Satellite technology is now providing direct evidence on the lengths and durations of these flights and associated staging episodes for individual birds. Using this technology, we compared the migration performance of two subspecies of bar‐tailed godwitLimosa lapponicatravelling between non‐breeding grounds in New Zealand (subspeciesbaueri) and northwest Australia (subspeciesmenzbieri) and breeding grounds in Alaska and eastern Russia, respectively. Individuals of both subspecies made long, usually non‐stop, flights from non‐breeding grounds to coastal staging grounds in the Yellow Sea region of East Asia (average 10 060 ± SD 290 km forbaueriand 5860 ± 240 km formenzbieri). After an average stay of 41.2 ± 4.8 d,baueriflew over the North Pacific Ocean before heading northeast to the Alaskan breeding grounds (6770 ± 800 km).Menzbieristaged for 38.4 ± 2.5 d, and flew over land and sea northeast to high arctic Russia (4170 ± 370 km). The post‐breeding journey forbaueriinvolved several weeks of staging in southwest Alaska followed by non‐stop flights across the Pacific Ocean to New Zealand (11 690 km in a complete track) or stopovers on islands in the southwestern Pacific en route to New Zealand and eastern Australia. By contrast,menzbierireturned to Australia via stopovers in the New Siberian Islands, Russia, and back at the Yellow Sea; birds travelled on average 4510 ± 360 km from Russia to the Yellow Sea, staged there for 40.8 ± 5.6 d, and then flew another 5680–7180 km to Australia (10 820 ± 300 km in total). Overall, the entire migration of the singlebauerigodwit with a fully completed return track totalled 29 280 km and involved 20 d of major migratory flight over a round‐trip journey of 174 d. The entire migrations ofmenzbieriaveraged 21 940 ± 570 km, including 14 d of major migratory flights out of 154 d total. Godwits of both populations exhibit extreme flight performance, andbauerimakes the longest (southbound) and second‐longest (northbound) non‐stop migratory flights documented for any bird. Both subspecies essentially make single stops when moving between non‐breeding and breeding sites in opposite hemispheres. This reinforces the critical importance of the intertidal habitats used by fuelling godwits in Australasia, the Yellow Sea, and Alaska.