The Abundance of the Eared (Black-Necked) Grebe As a Recent Phenomenon

-The Eared (Black-necked) Grebe (Podiceps nigricollis) is the most numerous grebe species in the world. Its status is largely a consequence of its abundance in North America where, unique among North American grebes, it is able to exploit the superabundant food resources of hypersaline lakes in the Great Basin. This results in high survivorship ofjuveniles during the critical first months of independence and of adults through the extended autumn staging period, and ultimately to increased population size. Because the major hypersaline lakes in North America are of post-Pleistocene origin, the Eared Grebe's current preeminence has likely been achieved only in the past several thousand years. Received 20 December 2000, accepted 22 February 2001.