National Bird Day - An Avocet Afternoon

American Avocet, Recurvirostra americana, feeding in the shallows at the Mission River Preserve in San Diego, California. What better way to spend the afternoon on National Bird Day than to go out and watch the migratory waterfowl at the Mission River Preserve in San Diego? As if they knew, the birds were out in full force! There were ducks, herons, egrets, grebes, cormorants and two types of pelicans plus gulls galore! The annual Winter waterfowl migration to San Diego always makes Winter days a whole lot cheerier.

American Avocet, Breeding Pair

A breeding pair of American Avocet, Recurvirostra americana at the Sonny Bono Salton Sea National Wildlife Refuge where, for conservation purposes, fresh water and food was introduced into ponds separated from the salty, polluted waters of the Salton Sea by dirt berms. To mate, the male flies up into the air in a short hop and wing flap and attempts to land on top of the female bird, similar to ducks, but with a bit of aerial acrobatics involved. These two have full red-brown breeding plumage. Their normal Winter colors are grey, black and white. I will note, however, that some of the breeding pairs retained their Winter colors so the color change did not appear to be a prerequisite for Spring activity.

American Avocets, Winter Plumage

American Avocets, Recurvirostra americana (so named for it's upturned beak -- aka recurved rostrum), resting on an exposed sand bar in the middle of the Mission River. Yes, the Avocets are back sporting their ever so stylish black and white formal Winter plumage! I had been to the Mission River for years without ever seeing an avocet until I realized that the little guys hang out in the shallows in the MIDDLE of the river, far from feral cats and stray dogs. Now that I know where to look, they're readily visible, albeit with a huge lens or perhaps binoculars.

I also puzzled for quite a while over the funky upturned beaks, wondering how they manage to eat anything at all with such beaks. However, it became fairly obvious upon watching them feed. They sweep those upturned beaks in shallow water over the mud and sand bottom kind of like a scythe cutting through wheat. The beaks scare up small water bugs and crustaceans which, as they are trying to flee the disturbance, become the Avocet's next meal.

So What Do Avocets Eat Anyhow?

American Avocet, Recurvirostra americana. As a follow-up to my last post, here's a close-up of an Avocet with food in his mouth. Is it food or just mud and rubbish? I stared at a bunch of these pictures, all with "food" in their mouths, and they vary a little bit. Generally, there were reddish-brown, longish things about the color of kelp in their beaks (plus some mud along for the ride). It does not appear to be kelp (far bigger pieces of that floating around). I'm sticking to calling it worms. However, if you know what Avocets eat, chime in. Curious minds want to know!

I found a page on the web that says that they eat "seeds, aquatic insects and small crustaceans," apparently including Brine Shrimp when they can get them. At this site, based on the photos I looked at, I'd probably rule out seeds or aquatic insects so maybe small crustaceans cruising on the mud? The mystery objects still remind me of worms though. I know the entire area is rich is worms which other co-located bird species feed on as well as clams which some of the birds either pry open or crack open (something to see!).

American Avocet

American Avocet, Recurvirostra americana, Winter colors. I only see these guys around at low tide. They dip their heads in a scythe like motion, reminding me of pigmy flamingos! (sorry, for the non-scientific comment but they do...) Oh, an yes, they close their eyes when they dip their head into the water.

How they EVER catch anything is beyond me. In fact, I've been trying to figure out how they catch anything at all with that upturned beak. Best I can figure, they stay in shallow water where they can skim the surface of the mud with their beaks, possibly catching worms or other critters at the surface of the mud. It's a totally different tact on catching worms versus their pointy billed bretheren that dive their beaks straight down into the mud to find their food. I'll have to review the pictures (I snapped a lot of them) to see if I can actually find one with a worm in his mouth. I vaguely recall seeing something long and stringy come up but it's almost always easier to see it in the pictures. Oh, and in case you're wondering, the bird book says that the females have the curvier (is that a word? Ahem, more upturned) beak!

American Avocet

A posting or two back, I promised a picture of an American Avocet, Recurvirostra americana. Well, here he is showing his lighter Winter colors. I had been pondering why their beaks are upturned so I did a little digging and found my answer. They use the base of their beak to stir up the mud and the little crustaceans which they prey upon. They also have a predilection for Brine Shrimp in the Great Salt Lake although they are more likely feeding on little amphipods in San Diego. Oh, and in case your Latin is a little rusty, Recurvirostra refers to the upturned (recurvi) nose (rostra/rostrum).