Western Tanagers must now be at the height of their numbers here, and we are fortunate to have them grace our landscape for a few short weeks every spring as their crowd flows north along “lush” Southwestern river valleys. From here at a certain moment they also migrate vertically to the coldest tops of the Rincon and the Catalinas, more than a mile above us. Every time I drive down The Lane the tanagers (often very handsome males) swing out from the branches along the sides and fly off in front of the truck for a ways along the track.
The species is a poster bird for the importance of preserving such valleys as this in the region, because it illustrates well what has been dawning on ecologists and biologists in recent years: the mountains of North America are re-populated every summer with many birds that come north along the ground between those mountain ranges, rather than along invisible routes high overhead. Much more use of places like the San Pedro and Santa Cruz valleys, the Lower Colorado, and the Rio Grande is made by the winged travelers than had been suspected. All along the way once they’ve left their wintering southern zones, the birds need amenities on the ground and each of these valleys has its human supporting and volunteer groups of naturalists and birders determined to see those amenities remain intact and available. It is hard to determine just how important having active agricultural lands like the Mason Pastures is to the continuing health of the West’s avifauna, but it doesn’t take much to imagine what would be the immediate and local effect of turning off the outflow pipe to The Stockpond, or of no longer watering these pastures that are in their way recreated grasslands.
The San Pedro’s “Ribbon of Green” itself certainly in importance is of the first magnitude, but for those other Southwestern watercourses there are claims made about the avifauna and its migration corridor that are indistinguishable from what is said about the San Pedro. It is pronounced for each valley and watershed by their fans, supporters and resident naturalists, This is the most important place! We have more migrants than anywhere! (an example: “Flora and Fauna in the Proposed National Heritage Area […] More than 400 species of birds […] About 200 migrating bird species; the largest number in the United States […] One area is ranked as the most critical area for biological conservation in Arizona […]” This is not the ridge-to-ridge watershed of the San Pedro that is being talked about here: it is the proposed Santa Cruz Valley National Heritage Area (see: http://www.santacruzheritage.org/files/file/chapter_03_smaller.pdf .)
Look long enough through many such papers available online and one can’t help but see the similarities to how one oppressed people or another around the world guarantee their being kept down when among themselves they compete for the title of most exploited or the most meanly treated. It plays right in with the exploiters’ winning game of keeping people from uniting and actually doing something about an insufferable reality. Determining once and for all which one of our Southwestern watersheds should get the title for most biologically important and so most-in-need-of-support is not a harmless academic exercise, for thinking within those frames would likely increase the possibility that the other places in the list be left to disintegrate to a perhaps unsalvageable state. Each corridor should be considered to have an importance of the first magnitude, for after all any number of different stars carry that label and the label still be wholly correct for each. The Colorado, the Santa Cruz, the San Pedro and the Rio Grande/Rio Bravo should be seen as a single, organic entity, and that no one of these is more significant than the others, since it will probably not preserve the wildness of any one of these “flyways” (or by extension, the faunal zones between here and the Arctic re-occupied every summer by these sojourners) if there is done anything less than protecting all four of them together.