Abstract
Extinction. We read about it. We hear about it. But we seldom think about it-that sometimes gradual, sometimes rapid demise of a species. To bird people it is mystifying, intriguing, sad. It arouses anger, pity, even greed. Yet sometimes it leads to serious, intelligent efforts for reclamation. The Socorro Dove, Zenaida macroura greysoni, it appears, may just be one such story.
The story has its beginning on Socorro Island. Now if the name doesn't sound familiar you aren't necessarily ill-informed. Few if any high school geography courses dwell on the Revillagigedos, a cluster of islands situated 210 miles south of the tip of Baja California. Socorro, the largest in the grouping, was once the homeland of a unique dove variety, whose discovery has been attributed to Edward Grayson, son of Andrew Jackson Grayson, naturalist and artist. In fact, the bird is also known as the Grayson dove but in this article I'll continue to use the island name.
This monumental find of an endemic species (one that is known to exist in no other habitat) occurred in the spring of 1867. According to the writings of Dr. Luis Baptista of the California Academy of Sciences, the Graysons, while shipwrecked on the island, made impressive collections and records of Socorro's flora and fauna. Among these collections were a great many discoveries as yet unheard of to science. And most significantly to our story was their first encounter with the Socorro Dove.
Grayson, a meticulous observer, kept fastidious notes on these birds. He also made detailed studies of avian numbers, behaviors and distribution. It was a grand beginning, which not many years later led to further explorations of the island.
Dr. Baptista mentions that scientists from the California Academy of Sciences made at least three pilgrimages to Socorro between 1903 and 1932. Each time a party visited the island the Socorro Dove was noted. Though distribution seemed to vary with the seasons, it appeared that the doves were especially drawn to high elevations where broadleaf tropical plants, including wild figs and wild currants grew in abundance.
What did the Socorro Dove look like? And how did these men know for a fact that this was a distinct species and not merely a subspecies of its closest living relative, the Mourning Dove?
First notes taken by early island expeditions pointed out the beautiful coloration of this bird. Unlike the...