Tracking reveals extreme nomadic flights by desert waterbirds seeking shrimp bonanza — ASN Events

Tracking reveals extreme nomadic flights by desert waterbirds seeking shrimp bonanza (#58)

Reece D Pedler 1 , Raoul FH Ribot 1 , Andrew Bennett 1
  1. Centre for Integrative Ecology, Deakin University, Geelong, Waurn Ponds, Victoria , Australia

In contrast to well-studied migratory species in temperate and predictable environments, birds in desert biomes face major challenges in exploiting stochastic, rich, yet short-lived resource pulses in vast arid landscapes.  Without regular seasonal cues used by migrants to prepare for spatially and temporally predictable annual movements, these species must somehow detect unpredictable resource pulses from afar and move there to take advantage, then successfully time their retreat to stable refuge areas.  Understanding of these complex, high-risk behaviours is limited, due to its unpredictable occurrence in the world’s remotest deserts. Using recent advances in satellite telemetry, we investigated movements by Banded Stilt (Cladorhyncus leucocephalus); a nomadic desert shorebird that breeds opportunistically in huge colonies on remote inland salt lakes after rare rain events trigger mass hatching of brine shrimp. Solar-powered 5 g Argos satellite tags deployed on 56 individuals revealed extensive, rapid and synchronised movements between inland salt lake breeding sites and coastal dry-time refuges.  Banded Stilts rapidly detected and moved towards inland wetlands following flooding, with birds flying 300-700 km overnight and undertaking exploratory journeys totaling thousands of kilometres.  Tagged individuals in different flocks showed common responses to distant cues; in one example two birds longitudinally crossed the continent, departing and arriving at the same points, yet travelling independently; one bird flying >2200 km in <2.5 days and the other >1500 km in 6 days. Individuals demonstrated rapid retreats to previously visited stable refuge sites, demonstrating use of stored individual or flock knowledge to successfully exploit unpredictable cycles.