Lesser Goldfinch In Sabino Canyon
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For those of you who are unfamiliar with Sabino Canyon, the canyon opens at its mouth into a broad and gently sloping desert. Like most of our desert, it can be exceedingly dry and blazing hot at certain times of the year and it is home to typical desert vegetation and animal life. As one heads into the canyon, the desert narrows and is eventually encompassed by the canyon’s walls. A stream — Sabino Creek — runs the length of Sabino Canyon, eventually passing into the desert at the canyon’s mouth. It flows with water about six months during the year and it is running robustly right now.
The creek is bounded narrowly on both banks by riparian vegetation. There are tall Cottonwoods and willows growing on the creek banks, definitely not desert plants. They survive because their roots are supplied with needed water by the creek. The riparian strip on each of the creek’s banks is narrow, only a few yards wide, and it continues for a half mile or more into the desert at the canyon’s mouth.
The riparian habitat by Sabino Creek is very different from the adjoining desert. Not only are the plants not desert plants, but much of the fauna one sees there consists of creatures that aren’t desert dwellers. The riparian habitat is thus unique: it is in the desert but it is not desert.
The other day I was walking just at the boundary between the riparian habitat and the desert. The boundary is quite distinct. There are plants that need fairly substantial amounts of water right next to classic desert plants. And, at this boundary a flash of yellow caught my eye. I looked closely and saw a male Lesser Goldfinch sitting on a mesquite, right at the boundary line between desert and riparian habitat.
This handsome little bird is definitely not a desert dweller. It is a species that likes brushy vegetation that is reasonably close to water, precisely the habitat that I was walking through. It was right at home in an exceedingly circumscribed habitat. The odds of my finding it in the desert, even a few feet away from where it was perched, were very low.
The goldfinch is a reminder that many species of birds and animals are specialists. They evolve to fill niches in particular habitats. Destroy those habitats and the fauna living there die off, even if killing the birds and animals is unintended.
In Arizona, humans’ exploitation of the land has caused the elimination of much of the riparian habitat. We’re realizing belatedly that what is destroyed cannot easily be brought back.
Images made with a Canon 5Diii, 100-400mm ISII zoom lens+1.4x telextender, aperture priority setting, ISO 400, f8 @ 1/1000.