Science-- there's something for everyone

Thursday, August 30, 2012

To attract native birds, plant native vegetation

I like this story for two reasons. First, it goes against my pre-conceived ideas and I always love that. And second, it gives practical suggestions for what people can do to make their yards friendly to birds. Susannah Lerman of the University of Massachusetts and her colleagues have found that wild birds can forage more successfully in yards with native plant life.

Why did this surprise me? The yards in question were in Phoenix, Arizona. That means that the researchers compared xeric (desert-like) gardens with mesic (moist, grassy) gardens. Although it seems obvious that birds would prefer native plants, I still thought birds would find more food in a lusher landscape. Not so.

Twenty homeowners volunteered their yards for science. The yards were divided evenly between mesic and xeric gardens. Two seed trays containing an exact number of seeds mixed with sand were placed in each yard. Thus, any bird feeding at a tray would have to spend some time sifting through the sand to pick out the seeds. At some point, each bird will decide that it’s no longer worth the energy or risk of predation to keep poring through the seed tray. The more food that’s available in the vicinity of the seed tray, the sooner birds will abandon it and forage elsewhere.

Birds stuck with the seed trays for much longer in mesic than in xeric yards. That is, the birds were less able to find the food they needed in the lusher yards than in the desert yards. The grass may be greener on the other side of the fence, but that’s no enticement to native birds.

Photo of a xeric, or desert, yard in Phoenix.
Photo of a non-native grass lawn in Phoenix with a house, garage and cars in the background.

Top: A xeric, or desert, yard in Phoenix: This yard with native vegetation is a mini-refuge for birds.
Bottom: A mesic yard in Phoenix, with its non-native grass lawn, is less attractive to native birds.
Credit: Susannah Lerman.

These data suggest that any homeowner who wishes to attract birds to his yard consider landscaping it with native plants. Since this also means that the owner will use less water and chemicals to maintain that yard, it’s a win-win for everyone.