Saturday, October 17, 2009

Cycles

In most autumns, the Rabbitbrush and Desert Broom burst into bloom, and they are both fabulous butterfly attractants. This year, after our very light monsoon, flowers are scarce around Portal, Arizona. But last week, Noel Snyder noticed an especially fine mass of Rabbitbrush blooming along the road from Lordsburg to Silver City in New Mexico. So we have set out with our friend Dick Zweifel, retired curator from the American Museum of Natural History, to learn what butterflies might be flying.


Rabbitbrush, Chrysothamnus nauseosus (Photo by Narca)

The answer is close to being negative data! Very few butterflies are flying at all this year, even where the Rabbitbrush is in fine fettle. It's the poorest butterfly flight year in the memory of local experts. Once again we are seeing firsthand the dramatic effects that drought can have, especially in a region that receives only modest precipitation even in fairly good years.

Another example––on the nearby Peloncillo Christmas Bird Count, Brewer's Sparrow numbers went from an all-time national high count of 13,462 in 2000, to zero just four winters later. These extreme fluctuations in populations responding to drought and flood argue strongly for long-term studies of wildlife! How can we understand a population unless we investigate the full cycle of bounty and stress?


American Snout on Desert Broom, Baccharis sarothroides (Photo by Narca)

On this field day, only American Snouts are flying in good numbers. Perhaps 60 are swarming around the Desert Broom, which is interspersed with Rabbitbrush. Here is a tally of the other butterflies: Checkered White 3; Orange Sulphur 5; Southern Dogface 1; Dainty Sulphur 1; Western Pygmy Blue 1; Variegated Fritillary 1; Painted Lady 4; and Monarch 2.

Only nine species! Last year, Dick recorded 40 species of butterflies at a single patch of Rabbitbrush!

Tuesday, October 13, 2009

At Fred and Melly's Cabin

It's just after dawn, and the rising sun hits our outside sleeping deck. We're in the mountains of central Idaho at the home of our long-time friends, Fred and Melly Zeillemaker. Fred retired from the US Fish and Wildlife Service after a career of managing national wildlife refuges from Oregon to Hawaii to Nebraska to Alaska. He and Melly retain an undiminished enthusiasm for all things wild.

The cabin is situated next to a small stream, lush with hawthorn and cottonwood, alive with hummingbirds and quail. Volcanic rock underlying this region is fractured and jointed, and springs rise to the surface along those joints. These springs support riverine trees and shrubs like Bitter Cherry, Chokecherry, Blue Elderberry, Saskatoon Serviceberry and Mallow Ninebark. The berries in turn feed birds, Red Squirrels and Black Bears. (No more sleeping outside when the bears return to the valley!)


Central Idaho (Photo by Narca)

Away from the streams, Great Basin sage and grassland reach into stands of Douglas-fir, Ponderosa Pine and White Pine, which grow mainly on the cooler, moister north slopes of the hills. Fall has touched the land with the reds of chokecherry and the golds of bitter cherry and ninebark.



Alan & Fred check the moths (Photo by Narca)

Our first night we set up a black light over a sheet and draw in moths. Under the UV light, gray moths are transformed into shimmering silver, or gray with exquisite silvery highlights, edgings and curliques. As I study them, a bat swoops over my head, feasting on the bounty.


Wilson's Snipe (Photo by Narca)

This morning's field trip takes us up Dodson Pass and down Sheep Creek Road. American Goldfinches forage on patches of sunflowers. A Wilson's Snipe feeds at the edge of a small creek. We wind through ranch land and sage to Crane Creek Reservoir, where a few lingering Baird's Sandpipers and American Pipits work the exposed mudflats. Where cracks lace the drying mud, tiger beetles scurry.


Are we mouse-proof yet? (Photo by Narca)

Wednesday, October 7, 2009

Finding Refuge in Nevada


Common Ringlet at Ruby Lake NWR (Photo by Narca)


The road north brings us to another stellar oasis: Pahranagat National Wildlife Refuge. Pahranagat means "valley of shining waters" in the Paiute language. Large thermal springs feed a system of wetlands, where impoundments assure water for thousands of migratory waterfowl and other wildlife. Alan and I visited the refuge once before, when two vagrants, an immature Mississippi Kite and a Zone-tailed Hawk, surprised us. The endangered Southwestern Willow Flycatcher nests at the northern lake.

With Rich Hoyer, we work our way along the shore of the southern lake. Rabbitbrush is in full bloom amid the shadscale, and the flowers are a magnet for insects. One butterfly is new for all of us, the Mojave Sootywing. This very small skipper, barely larger than the Western Pygmy Blues, is a saltbush specialist.


Rich Hoyer peruses the Rabbitbrush (Photo by Narca)


Imperceptibly, the warm Mojave Desert is grading into the cold Great Basin Desert. We begin to see Big Sage, the indicator plant for the Great Basin. Pahranagat's northern lake and campground are closed for repairs to the dam, so reluctantly we continue north toward a national wildlife refuge that is new for us, Ruby Lake.

First comes a lunch stop at the Silver Cafe in the old mining town of Pioche. Photos on the wall depict various atomic bombs exploding at the Nevada Test Site. It's hard to imagine that anyone close enough to take those photos lived for very long afterwards. At long last, closures due to lingering radiation at the test site have recently been announced.

Still pondering the long-overdue closures, we arrive at Ruby Lake NWR. Ruby Lake supports the largest nesting population of Canvasbacks in the western US. Like many western valleys with remnant wetlands, this valley was the site of a huge Pleistocene lake––Ancient Lake Franklin––about 12,000 years ago when the climate was wetter. Today more than 200 springs feed the refuge wetlands.

We don't have time for more than a short hike along a rushing, willow-lined stream, but the drive has been well worth the effort. The scenery of this isolated region is magnificent. The Ruby Mountains tower over a near-pristine valley. While we are here, a sudden plume of smoke announces the start of a prescribed burn in the Rubies, an effort to reduce the fuel load and reestablish the natural fire regime.

Our final campout on the road north is at Great Basin National Park. Now we've completely made the transition to this cold desert, which lies in the rainshadow of the Sierra Nevada and Cascade Mountains. The Great Basin is exactly that––a 200,000 square-mile region of hundreds of northwest-to-southeast trending basins and ranges, all with only internal drainage. All waters eventually evaporate or sink underground; none flow to the sea.

Wheeler Peak, at over 13,000 feet, shadows the national park. A system of about 40 caves laces the park, with Lehman Cave the best known and most developed. Fractures in the bedrock were created when the mountains uplifted, and acidic groundwater flowed along those fractures and dissolved the marble to form this cave. Some of the dissolved minerals were redeposited to form the unique, very beautiful formations of this living cave.


Aspens at Upper Lehman Campground (Photo by Narca)


We ascend to high-elevation forest of conifers and aspen, with their attendant Steller's Jays, Red-breasted Nuthatches and Townsend's Solitaires. In the dusk, the bark of aspen glows dramatically white. We fall asleep to the sound of the rushing mountain stream.

Saturday, October 3, 2009

Nevada Oasis

The long drive north from Arizona to Idaho brings the perfect opportunity to revisit our favorite refuges in Nevada and to explore new ground. We pick up our friend Rich Hoyer in Tucson, and the three of us set off on a three-day camping trip through the vast, stark Nevada desert.

The Sonoran Desert grades into the Mojave as we exchange Saguaro for bristly, imposing Joshua Trees. The rainfall regime changes as well: Mojave Desert receives mainly winter rain; Sonoran Desert usually receives both winter and summer rains and is lusher.

Just a half-hour north of the glitter of Las Vegas lies a gem of an oasis: Corn Creek Field Station, a part of Desert National Wildlife Refuge. This refuge's 1.5 million acres encompass six mountain ranges, which are home to Desert Bighorn Sheep. Over the years, Alan and I have stopped at Corn Creek every chance we've had. During migration it often produces an impressive array of western migrants and eastern vagrants, such as White-eyed Vireo and Palm Warbler. Corn Creek is also a northerly nesting outpost for several typically southwestern birds, including Lucy's Warbler, Verdin and Vermilion Flycatcher.


Alan Craig & Rich Hoyer at Corn Creek (Photo by Narca)

We arrive in late afternoon, make a quick circuit of the spring-fed ponds, and set up camp not far away. (It's still possible to rough-camp here for free.) The 100-degree day cools with the setting sun, and Coyotes begin to sing. Soon the vast starfield stretches over our two tents, alone in the immensity. A glow to the south marks Las Vegas.

At dawn we're up, break camp, and return to Corn Creek. We meander along the paths through thick vegetation. Cedar Waxwings pluck fruit from the Russian Olive trees. A Red-shouldered Hawk (unusual in Nevada) swoops to a post next to a small pasture. Endangered Pahrump Poolfish fin through the ponds. We find a nice showing of western migrants––Peregrine Falcon; Willow and Gray Flycatchers; Nashville, Virginia's and MacGillivray's Warblers; Yellow-breasted Chats; Lazuli Bunting––before continuing our journey north.