It would be hard not to notice an American Avocet – these large shorebirds, with their long blue legs and delicate-looking upturned bill are almost unmistakable. When taking flight, adults often give a high pitched kleet-kleet-kleet call, circling overhead with their neck extended and long legs straight out behind them.
American Avocets specialize in using ephemeral wetlands of the arid western United States, and are effective indicators of environmental stressors within western wetlands. I often see American Avocets (along with a number of other interesting wetland species like Black-necked Stilts, Soras, and Great Egrets) at a remarkable spot in Valencia County locally known as “Belen Marsh.” Belen Marsh is an artificial wetland that was created accidentally, when soil was taken from the area for nearby construction projects in the early 1990s. Because the water table there is so close to the surface, the depression filled with water. It wasn’t long before native plants moved in, and soon the birds followed. Over 178 bird species have been seen at Belen Marsh, and it has become a well-loved spot for birders in central New Mexico.
A large percentage of American Avocets in the west now use artificial wetlands for roosting and breeding, because the vast majority of aridland wetlands have been destroyed, drained, filled in, or otherwise so highly modified as to be of little use for birds. For example, more than 80% of the estimated 40,700 Black-necked Stilts and American Avocets summering in California's Central Valley were found in environments created for agriculture, water management, and industry. Because these human-created habitats rely on continued maintenance and operation, their future usefulness for birds is unknown. Additionally, artificial habitats are not as likely as natural habitats to include predator-safe islands for nesting, and routine upkeep of these facilities, including road grading and levee maintenance, destroys countless eggs and nests every year.
The diet of the American Avocet is quite varied, and includes aquatic and terrestrial invertebrates, small fish, and some plant material such as seeds. They search for food while wading in shallow water, picking food items from the surface of the water or plunging their head and neck into the water to grab aquatic prey. They also capture food while swimming in deeper water, and grab flying insects in the air. Generally, they prefer a substrate of mud instead of sand, because it is easier for them to filter out food particles from finer sediments.
Aquatic insects are very sensitive to environmental pollutants, which is why American Avocets are often associated with high-quality wetland habitat. Invertebrates that Avocets and other wetland birds depend on, such as water boatmen, adult and larval beetles, midges, flies, and all sorts of aquatic worms, are harmed by chemicals from agricultural runoff. In the arid West, wetlands both natural and man-made must compete with urban and agricultural interests for limited supplies of fresh water.
Audubon Southwest works closely with water users and water managers in New Mexico and Arizona to ensure that birds and their habitat get their fair share of clean water in the places that they need it, when they need it. The future of the West is uncertain – water in the Rio Grande and other western rivers is over-allocated, and climate change is impacting the Southwest by causing hotter summers, a disrupted monsoon rain cycle, and lower snowpack in the mountains that feed our rivers. Audubon collaborates with water managers, water users, and policy makers to ensure that, when big-picture water decisions are being made, birds including the American Avocet, have a seat at the table.