“Odds and Ends”
This spring’s moisture had me thinking that we would be safe from fire danger until after the July monsoons, but nature threw a curve with a hot and dry last half of May through June. How warm did it get?
I was up on the flanks of Bald Mountain in mid-June conducting an Indian Peaks Bird Count. In search of brown-capped rosy-finches, I headed over to a snowfield where I had seen them in past years picking out insects that had been blown into the snow.
I could see the snowfield over a slight rise about a half mile away and noticed a cluster of objects on its lower slope. Using field glasses, I discovered they were 50 elk all on the snowfield, with some young that were running and sliding on the snow. Even they were looking for a cool place to beat the heat.
There have been a number of rare bird sighting in the mountains. Ovenbirds were heard and seen in several locations in Boulder County. This small warbler that nests on the ground is best found by hearing its distinctive song, two-part notes that increase in loudness and sound like teacher teacher teacher. The small population of them in Colorado is restricted to a narrow strip along the Front Range from Larimer County to New Mexico. Other rare finds this summer included blue grosbeak at Caribou Ranch Open Space, two sandhill cranes flying over the Arapaho Ranch, and 18 white-winged crossbills near the Rainbow Lakes campground.
Last summer we witnessed the “Brewer’s sparrow/sage thrasher krummholz invasion.” These two species, normally found in lower elevation sagebrush habitat, have recently been present in the krummholz near treeline, with peak numbers occurring in 2002 and 2012.
Their appearance is possibly climate-change related. Warm, dry springs appear part of the pattern for them to occur, so when the heavy snows came in April and early May we thought we would see few if any. True to form, no sage thrashers were observed and only a handful of Brewer’s sparrows were detected.
Besides the expansion of species from lower to higher elevations, there has also been a long-term movement of bird species up the lower Front Range. The blue-gray gnatcatcher is one of those species.
We sometimes see them in the Nederland area in fall, but the shrublands of the lower foothills are their primary breeding habitat. Historically, they were considered to be present along the Front Range of Colorado south of Denver. In the late 1980s they were found in Douglas, Jefferson, and Boulder counties, and in the early 1990s they were found nesting in Larimer County.
These past few years I have been spending time conducting bird inventories around Lyons, where there are abundant shrublands dominated by mountain mahogany, skunkbrush, hackberry and juniper. Blue-gray gnatcatchers are now fairly common breeders in the dense shrubs.
Black-chinned hummingbirds are also a new arrival to the fauna of Boulder County, again slowly moving north up the lower foothills of the Front Range. I stumbled upon a nest this summer, placed on the branch of a juniper.
Gray flycatchers are now being spotted in the foothills of Boulder County. Ash-throated flycatchers are probably not far behind, and I thought I heard a gray vireo this summer. I call this group the blue, black and gray birds, generally associated with drier habitats, particularly piñon pine and juniper, and more common in western Colorado, Utah, Arizona and New Mexico. The warmer climate may be playing a role in their slow march north, where they are finding suitable habitat in foothill shrublands.
Looking ahead, August is normally a continuation of summer, but the last half can bring harbingers of fall, including the first frost and the appearance of yellow on a few aspen leaves. Other August nature happenings in the Nederland area follow.
Most of our wildflowers will be past their peak, though the colors may linger with adequate moisture and mild temperatures. The yellow showy golden-eyes are one of the last composites to have a major bloom.
Porter aster and owl-clover are also late-season bloomers. This can also be a good month for blooming gentians; look for the white arctic gentian on the tundra. Warm season grasses, such as mountain muhly, bloom this month. Berries ripen; start looking for huckleberries during the last half of the month.
Like the flowers on which they depend, butterflies are also past their prime, but many will linger while the weather permits. The dark-colored small wood-nymphs will dominate mountain meadows.
The yellow and orange Meade’s sulphurs will be active on the tundra. Look for the large black-and-white Weidemeyer’s Admiral around aspen and willows.
Mammals will provide hints of fall. Elk will still be in their summer herds, but some bugling will be heard towards the end of the month. Pine squirrels will start dropping cones from trees, building up their winter food reserves.
Underground pocket gopher activity will increase, evidenced by more mounds of dirt in meadows. Black bear scat will begin to change in composition from grass to berries.
Birds are finishing getting their young out of the nest. They will start forming flocks with an eye toward migration. During the last two weeks of August and into September there is an upward migration of birds. Many sparrow species, bluebirds and raptors are seen on the tundra.
Crickets and grasshoppers become abundant in subalpine meadows and on the tundra.