Tuesday, January 31, 2012

Liminal Birds

Liminal is a nifty word that describes the border between two different things, be they cultures or environments. The liminal space is where elements of both overlap and interact, sometimes harmonizing and sometimes coming into conflict.

Many birds seem to prefer the liminal spaces of nature. I certainly gravitate towards these areas as a birdwatcher, probably because it's easier to see and target places that have lots of distinction. It's much harder to make oneself survey a homogenous landscape than one with many different features on which you can easily focus. Observe the liminal spaces at the Gilbert Water Ranch, those areas where land meets water, where the chaparral meets the trees, and these are some of the species you'll likely find:

The Northern Shovelers are not very good divers, but they do like to feed off of the bottom of ponds. As such, they're limited to the shallow areas where they can go bottoms-up. Locating Shovelers in a pond is a good way to guess at the depth of the surrounding water.

 The Black-Necked Stilt is not a swimmer, but it likes to feed in the mucky muck just like the Shoveler. Consequently, it too is destined for life in a liminal space.

The Common Gallinule (formerly known as Moorhen) makes its nest in the reeds and bullrushes around the water, and is seldom seen very far away from its precious cover. I'm not really sure what they eat, but if if it's true that you are what you eat, then looking at the beak I'd say they eat candy-corn.

The water's edge draws all manner of other birds, including warblers, wrens, waterfowl, herons, kingfishers, and shorebirds ad infinitum. There are also many birds that prefer the dryer liminal spaces. The Sparrows and Finches in Arizona like to move between the higher trees, which provide more cover, and the seedy grasses that provide better but lower foraging. I found my first ever Lawrence's Goldfinches moving between the trees and grasses at the Water Ranch, and they were also accompanied by lots of Brewer's Sparrows.

My fondness for these margins sometimes inhibits my birding. I often spend too much time looking at these areas, which can attract many different species of birds, and miss the less conspicuous specialists who stay in a specific environment. But hey, whether you bird in the margins, or immerse yourself in one specific environment, it's all good. Birding is fun.