Dave Hallock, Eldora.  As their name implies, "swifts" are fast-flying birds. In fact, they are considered to have the swiftest flight among small birds. They probably spend more hours in flight than any other land bird. All food-gathering, courting, drinking, bathing, and similar functions are done while flying. While similar to swallows, they are not related.

Swifts have a very different flight characteristic that makes it easy to distinguish them from swallows at far distances.  The wings of swifts have short, massive bones compared with slender bones of swallows; this rigidity of swift's wings make their flight seem "herky-jerky" compared to swallows.

There are three types of swifts found nesting in Colorado. Chimney swifts are found in urban areas on the plains. White-throated swifts are found in foothill canyons: they are present in Boulder Canyon. Black swifts are our least common swift. They nest behind waterfalls and spend most of their daylight hours in the high atmosphere searching for aerial insects.

In Colorado, black swifts are best known from the San Juan Mountains, particularly the waterfalls at Ouray. But there are some Front Range nest sites, including three in Boulder County. The best known nest sites are in Rocky Mountain National Park at Calypso Cascades, and Ouzel Falls in the Wild Basin area.

But another colony is present along the falls coming out of Diamond Lake. Many years ago Allenspark naturalist Mike Figgs and I hiked down the falls from the lake and then back up in search of their nests and found a small colony present.

Their nesting and feeding habits make them hard to find. Their nests consist of well-built cups of moss and mud placed in a niche on sheer rock cliffs. The sites are well-shaded and bathed in the mist from a waterfall. They are late arrivers and nesters, often laying eggs well into July or even August and still having young in the nest in September. Adults spend most of their daylight hours far away from the nest, only to return at dusk and then leaving at first daylight.

This past summer, while conducting breeding bird inventories for Colorado State Parks, I was assigned the task of reconfirming a black swift colony at Rifle Falls, a small, beautiful state park just north of the Town of Rifle. In mid-July I camped at the park and went to the known nesting site around dusk. Kim Potter, a biologist for the White River National Forest, was one of the people to find this colony and gave me good information on where they nest. What followed was a prime example of "Pissoffski's Second Law of Being In Nature."

(I will digress for a second.  The famed, mythical European naturalist I.M. Pissoffski has a series of laws about nature that many of us have experienced.  Pissoffski's First Law of Being in Nature says, "If you are hiking and stop to take a leak, someone else will come along the trail." I would guess most of us have experienced this law. His second law says, "If you are actively searching for an animal, it will only appear when you have given up on finding it." I have had this happen many a time when searching for white-tailed ptarmigan on the tundra.)

Well, my experience with the black swifts at Rifle Falls would fit his second law. I was there at dusk. There were many swallows, mostly violet-green and cliff, flying around the waterfalls catching insects. In a small hole in a rock there had to be a Cordilleran flycatcher nest, as I watched two adults coming and going every couple of minutes, flying in and then quickly out of the hole. But no swifts.

It was almost dark, and in my mind I had the thought that this colony may not be active this year. And then they came. First one, with the tell-tale herky-jerky flight pattern, then eight or nine more, all flying around the falls in the described nesting area. I watched as they collected moss and were working on constructing their nests. Rarely do I get to see them this close being so industrious. For me it was pleasant dreams shortly after.

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. 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 occur 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 (except for black swifts). 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. The birds are feeding on crickets and grasshoppers, which become abundant at higher elevations.