The islands of the Gulf of California are called "the Mexican Galapagos." Most have many unique species or subspecies. Isolation and limited resources have created such wonders as the dwarf giant barrel cactus and the rattleless rattlesnake. It's our pleasure to discover these and other insular peculiarities. Yet there is another “island” in this region. The Baja California peninsula is isolated and functions as a biological island.
Today we visited Isla San Jose. Recent rain has swathed the island in greenery punctuated with bright floral displays. As if the color were not enough, butterflies danced around the flowers. We saw orange queen butterflies, closely related to the familiar monarch. We also saw white and yellow cabbage butterflies. Birds, too, were attracted to the flowers. The most common hummingbird here is the Costa's. It's always fun to see these avian speedsters, but even better is the Xantu's. This hummingbird is endemic to Baja California—a unique product of evolution on this "desert island."
Most of us were fortunate enough to see at least one Xantu's hummingbird. This female was feeding from a patch of malva rosa flowers. Her yellow forehead was a bit of a surprise, since no Mexican hummers are truly yellow. The color is actually a heavy dusting of palo adan pollen.
With luck we might see the hummingbird from which the Xantu's is derived. The mountains around Copper Canyon are home to the white-eared hummingbird. Long ago this species colonized Baja California in the same way the ancestor of many a unique species colonized the islands of the Sea of Cortez.
