Within a week of a big storm transforming a salt-encrusted desert pan into a lake, thousands of banded stilts may arrive from the coast - hundreds or thousands of kilometres away. How they know that rain has fallen is a mystery. At the lake, they feast on 'brine shrimp soup' - a rich banquet of crustaceans whose eggs lie dormant in the salt crust for years between rains. Within a few days of feasting, the banded stilts lay 3-5 eggs in a scrape on the ground. If the lake does not dry up and if they survive predators, the chicks hatch and fledge in about 85 days.
Between 1930 and 2010, just 30 breeding events for banded stilts were recorded. Two researchers who chanced across a massive breeding event on Lake Barlee in 1980 counted 179,000 nests, in densities as high as 18 per square metre, on 3 islands in the lake. The big breeding events are all precipitated by large inland rains. Recent research has shown that small numbers of banded stilts breed in response to almost any inundation of a salt lake. But many have to abandon their eggs or chicks as the lake dries up. They have only a 30% chance of the eggs hatching and a much lower probability of chick fledging.