This video shows behaviors of waterbirds at Lake Abert - a threatened salt lake in southcentral Oregon that attracts hundreds of thousands of shorebirds each year. Additional shorebirds at nearby Summer Lake are included. Waterbirds migrate to Lake Abert because of the high abundance of brine shrimp and alkali flies on which the birds feed before migrating south for the winter. Some of these birds fly 5,000 miles from Oregon to saline lakes in South America. Over 80 species of waterbirds have been reported from the lake, but the most numerous are phalaropes which have an unusual feeding behavior - swimming in circles to create a vortex that brings prey to the surface.