Extreme nomadism in desert waterbirds: flights of the banded stilt

Abstract

In contrast to well-studied Northern Hemisphere birds with spatially and temporally predictable seasonal migrations, waterbirds in desert biomes face major challenges in exploiting stochastic, rich, yet short-lived resource pulses in vast arid landscapes, leading to the evolution of nomadic behaviour. An extreme example is the banded stilt (Cladorhynchus leucocephalus), an opportunistic colonial breeder at remote inland salt lakes after infrequent rain events. Using satellite telemetry on 21 birds (tracked for a mean of 196.2 days), we reveal extensive, rapid and synchronized movement among individuals to and from salt lakes. Two birds left coastal refugia for the inland following rain, flying 1000-2000 km, while 12 others rapidly moved a mean of 684 km (range 357-1298 km) away from drying inland sites to the coast. Two individuals moved longitudinally across the continent, departing and arriving at the same points, yet travelling very different routes; one bird moving more than 2200 km in less than 2.5 days, the other more than 1500 km in 6 days. Our findings reveal movements nearly twice as long and rapid as recorded in other desert waterbirds. We reveal capability to rapidly detect and exploit ephemeral wetland resource pulses across the stochastic Australian desert.

Partial migration in a subtropical wading bird in the southeastern United States

“…, Pedler et al. ). Some bird populations exhibit facultative migration when a key environmental factor that drives the availability of resources exceeds a critical threshold (Streich et al.…”

“…Studies on how unpredictable resource dynamics drive migratory movements of non‐temperate wetland dwellers other than wading birds are also few, but see, for example, Bennetts and Kitchens () and Pedler et al. (). In this paper, we provide a quantitative description of migratory patterns of a subtropical wading bird in the southeastern United States, the wood stork ( Mycteria americana ).…”

“…However, even seemingly nomadic or irregular movements can be considered migrations if their function is to allow the exploitation of resources that do not follow seasonal fluctuations (Dingle 1996, Roshier et al 2008, Van Moorter et al 2013. For example, ephemeral resource outbreaks with no periodicity often lead to erratic migration (Kingsford et al 2010, Pedler et al 2014. Some bird populations exhibit facultative migration when a key environmental factor that drives the availability of resources exceeds a critical threshold (Streich et al 2006).…”

“…Nonetheless, few studies have explicitly quantified migration patterns of wading bird species (but see Mckilligan et al 1993, e.g., on cattle egrets, Bubulcus ibis) and, to our knowledge, none in non-temperate areas. Studies on how unpredictable resource dynamics drive migratory movements of nontemperate wetland dwellers other than wading birds are also few, but see, for example, Bennetts and Kitchens (2000) and Pedler et al (2014). In this paper, we provide a quantitative description of migratory patterns of a subtropical wading bird in the southeastern United States, the wood stork (Mycteria americana).…”

Ecology and conservation of Australia’s shorebirds

“…or Paratemia spp. populations peak in large ephemeral salt lakes (Collard et al, 2010;Pedler et al, 2014). Human activity, such as river regulation tends to dampen both the magnitude and duration of many pulses in resource availability (Kingsford, 2000), and…”