Elegant American Avocets

It's been a few weeks since my last visit to our local wetlands (namely, the San Luis, Merced and San Joaquin River National Wildlife Refuges) but even from my vantage point in my own backyard, I can tell you that exciting things are happening in the avian world!  Spring migration is in full swing, and birds we have been eagerly waiting for have returned: swallows, flycatchers, orioles, tanagers, warblers and vireos are filling the riparian woodlands (for a more complete sampling, check out the last few posts by Garry Hayes over at Geotripper's California Birds!)  The bird composition has been changing in my backyard as well - the Yellow-rumped Warblers and White-crowned Sparrows of winter have departed (heading north and up-slope into the Sierra) while Cliff Swallows and Swainson's Hawks have arrived!

In the wetlands, one of the most elegant birds of late spring is perhaps the American Avocet (Recurvirostra americana).  While they are present in the Central Valley year-round, they seem to be most conspicuous, and certainly most brilliantly colored, in late spring.

Long-legged shorebirds with long, up-turned bills, American Avocets are designed for life in the shallows where they spend their time foraging for aquatic invertebrates.

By sweeping their bills side to side just beneath the surface of the water, they are able to capture small aquatic insects and their larvae, along with small crustaceans.  In the western United States (especially at places like Mono Lake) their diet includes brine shrimp (sea monkeys!) and brine flies.  Other foraging methods include pecking at food items or even plunging their heads underwater to nab a tasty morsel.  Foraging methods vary with food availability, which varies with location and season.

American Avocets are commonly found foraging in loose flocks, often associating closely with related Black-necked Stilts.  During the breeding season, they also nest in loose mixed flocks of avocets and stilts.  

Nests are little more than shallow scrapes on bare, open ground near water, tended and defended by both parents.

Though populations of American Avocets appear to be stable, like so many species, they are vulnerable to loss of wetland habitat.  Interestingly, while the practice of draining wetlands during the early 1900's nearly spelled disaster for avocets and related species, the concurrent building of salt ponds, rice fields, sewage ponds, dairy lagoons and other trappings of expansion created enough acceptable habitat for the American Avocet to continue to be successful.