THE BIG PICTURES: THE CHIRICAHUA MOUNTAINS

LEFT: Maple leaves display their autumn hues in the Chiricahua Mountains' Cave Creek Canyon. In addition to its plant life, the canyon is known for the roughly 370 bird species and 170 butterfly species found there.

RIGHT: Determined plants grow on an outcropping of a weathered rock wall in Cave Creek Canyon. Forest Road 42, which runs from Portal to near the Chiricahua National Monument entrance, offers good views of Cave Creek Canyon and neighboring Pinery Canyon.

Afternoon light illuminates hoodoos in Chiricahua National Monument's Rhyolite Canyon. The hoodoos are the result of water repeatedly filling vertical cracks in rock, then widening those cracks when it freezes and expands - eventually leaving columns of rock behind. Jeff Maltzman

Southwestern Research Station

Twice a year, birders flock to the Chiricahua Mountains clutching life lists and hoping for a glimpse of tropical migrants and the 17 or so signature species of Arizona's "sky islands." But only a lucky handful score a spot on one of the birding tours offered by the Southwestern Research Station in Portal. The field station, which operates under the direction of the Science Department at the American Museum of Natural History in New York, typically serves biologists, geologists and anthropologists interested in studying the diverse environments of the Chiricahua Mountains. But in April and September, non-researchers have a chance to get in on the action through one of the station's nature tours. In September, participants might see white-eared and berylline hummingbirds, three or four species of butterflies that take flight only in the fall, and as many as 100 species of flowering plants. "To me, September is one of the best months to come here," says Dawn Wilson, the station's former director. "It's still birds, and great birds, but it's got all sorts of other things going for it."

This month's Monsoon Birding and Natural History Tour takes place September 2-8. For more information, contact the Southwestern Research Station at 520558-2396 or visit www.amnh.org/swrs.

LEFT: Lichen-stained hoodoos loom over the Echo Canyon Trail at Chiricahua National Monument. This trail is part of a scenic 3.5-mile loop hike that also features the Hailstone and Ed Riggs trails. Paul Gill RIGHT: Water tumbles over a small waterfall and into a placid pool in Cave Creek Canyon. Paul Gill

"A pile of rocks ceases to be a rock pile the moment a single man contemplates it bearing within him the image of a cathedral." - ANTOINE DE SAINT-EXUPÉRY