By early September, bull Elk may be starting to bugle in the upper reaches of streams, sounding like a whistle followed by a series of grunts. Many Elk have spent the summer in the high mountain meadows, feeding on the lush vegetation. Now it is the beginning of their breeding season, and the bull’s bugle communicates dominance to cows, and may be given as well in aggressive encounters with other bulls. Beargrass holds elongated clusters of seedpods, which Elk and Chipmunks eat. Black Huckleberries are ripe near the peaks, and the bushes are turning a brilliant red as the leaves lose their chlorophyll. Ever since the summer solstice, the sun has been tracing a lower and lower path across the southern sky, and the hours of daylight have gradually been decreasing. The longer nights are the main signal that triggers deciduous trees to build a corky layer between their twigs and their leaves, blocking the replenishment of chlorophyll and eventually causing the leaves to turn color.
If you are lucky, you may spot a large, old Whitebark Pine bearing plum-sized, purplish brown cones. Strictly a high-elevation species, this pine is an important food source for wildlife. It is considered a keystone species – one whose loss would have cascading effects on the community. The almost pea-sized, high-protein seeds are an important food for Clark’s Nutcrackers, unique gray, white, and black corvids with long bills. These birds cache seeds, often on open south-facing slopes, retrieving them during the winter and their early breeding season the next spring, but also leaving some, which may grow into new trees. Whitebark Pines depend almost exclusively on these birds for tree regeneration. Other animals also feed on these high-protein, high-fat seeds, including Red Squirrels, Black Bears, and Grizzly Bears.
Whitebark Pines have declined ominously due to a combination of factors. White Pine Blister Rust, a disease caused by a human-introduced fungus, has affected them profoundly. Fire suppression, allowing the more shade-tolerant Subalpine Fir and Engelmann Spruce to replace these trees, has been another factor in their decline. A third factor is the Mountain Pine Beetle, a native species that attacks all our local pines in irregular outbreaks. These insects have become more of a concern at high elevations as the climate warms; cooler temperatures are less favorable for beetle growth and development. In a recent determination that Whitebark Pine warrants listing under the Endangered Species Act, the US Fish and Wildlife Service projected that, if current trends continue, these trees will be extirpated in the foreseeable future.
Ghost forests of Whitebark Pine snags, their barkless trunks bleached white, are a stark reminder of what once was – and what might be again. Scientists with the US Forest Service, with assistance from FSPW volunteers, have conducted Whitebark Pine surveys, looking especially for mature cone-bearing trees demonstrating genetic resistance to the Blister Rust fungus. Restoration work is underway, including seed collection and propagation of those trees that show natural genetic resistance. Prescribed burns are an excellent tool in this effort, removing species such as Subalpine Fir that have expanded their presence due to fire suppression, and creating conditions favorable for Whitebark Pine regeneration.
In the meanwhile, seeing a mature, healthy Whitebark Pine, heavy with cones, is a sight to be thankful for.
The weather is changing noticeably. The nights are growing cooler, and storm systems may be moving through, wrapping the mountains in clouds. Perhaps, as the air clears and the barometer rises after several days of cold, gentle rain, you may see a dusting of snow on the highest peaks – a hint of what is to come.
An astonishing variety and number of mushrooms are poking up in the forest, triggered by the cooling weather and by rains. If you find mushrooms stuck on tree limbs or in crotches, you may be seeing the work of Red Squirrels, which are known to dry them for winter consumption.
By the middle of September, Western Redcedar cones are ripening, and frosts have touched the higher altitudes, or will soon. In the upper reaches of streams, the large, broad, spiny leaves of Devil’s Club turn brown with the frost. The pinnate leaves of the low-growing Wild Sarsparilla are a bright golden, as is the foliage of the ubiquitous Bracken Fern. Paper Birch and Black Cottonwood are starting to show some yellow in their leaves, and Serviceberry bushes seem to be glowing. Fireweed is generally finished blooming, and its seedpods are opening to reveal many fluffy white seeds, which will be carried by the wind to new homes.
We pass the autumnal equinox, September 22. Day length has been decreasing predictably since the summer solstice, and for this one date the day is as long as the night, everywhere on the planet. In the proposed wilderness, the sun will trace a lower and lower path across the sky and the days will grow shorter and shorter for the next three months. Many of the birds that raised young here this summer have left on their long migrations. As we move towards a time of increasing cold and dark – of hibernation, dormancy, and survival – the progression of the seasons is apparent in many ways in the natural world.
The mountain ridges and the upper creek drainages are stunning at this time of year: yellow leaves on the Rocky Mountain Maple and False-azalea contrast with the dark green steeples of Subalpine Fir and the burgundy-red leaves of Black Huckleberry. The black-blue fruits of the Huckleberry may stay on the low-growing bushes after the leaves have already fallen. Black and Grizzly Bears, Chipmunks, and some species of birds might take advantage of these late berries, no longer hidden by the leaves. Migrating Yellow-rumped Warblers, many having nested far north in Canada, are conspicuous, refueling on insects here before continuing their journey. Some Yellow-rumps winter in the southern US or along the Pacific coast, farther north than many warblers – they are one of the latest migrants in this colorful avian family.
Ruby-crowned Kinglets are still around, too, hovering at the tips of branches to glean small insects. They may not migrate very far: some may spend the winter in southern Idaho. You might hear the “see, see, see” calls of their hardier relatives, the Golden-crowned Kinglets. These tiny birds with a striped black and white face remain around here all winter, searching for insects, spiders, and their eggs on tree foliage and bark. Hermit Thrushes have been relatively quiet for the last two months, but you might still hear one singing its flutelike melody, especially during cool, damp weather. While other closely related Thrushes make long seasonal journeys to southern Mexico and South America, the Hermit Thrush is a relatively short-distance migrant, with birds wintering along the Pacific coast, in the southern US, and in Mexico.
By early October, the leaves of the Black Cottonwoods are bright yellow and beginning to drop, covering the earth around them with blotches of gold. These trees like moist sites, and in the mountains you will often find them growing along an old roadbed, where the slow movement of water down the slope has been blocked and channeled. If you look closely at the Western Larches, unusual in being deciduous conifers, you may notice a hint of yellow in their needles already. Mountain-ash leaves are matching the colors of the Cottonwoods, and falling to the ground, leaving the naked stems and red fruit clusters behind. You might find a large pile of bear scat, composed almost entirely of red-orange Mountain-ash pomes. It is breeding season for Moose; keep an eye out for their muddy wallows, smelling strongly of urine, which both sexes may roll in. Unlike breeding male Elk, which gather and defend a harem of cows, bull Moose will mate with one cow and then move on in search of another, sometimes fighting with other bulls but not mate-guarding a group of cows. Blue Elderberries are ripe, and American Robins, House Finches, and Northern Flickers are among the birds who are attracted to the blue-gray clusters of peppercorn-sized fruits.
By the middle of October, the Western Larches are turning golden at the higher elevations, and those in the valleys are not far behind. The mountains look as if they are molting; the Larches, Cottonwoods, Aspens, and Birches are golden-yellow against the dark blue-green of the conifers. Periods of cloudy, rainy weather are no surprise at this time of year. Clear, cool fall days are magnificent, but it seems that the Larches glow most brightly when clouds hide the sun. American Robins and Varied Thrushes are not making themselves conspicuous, but an occasional burst of calls from the treetops, or a seemingly out-of-place song, may tell you that some of these birds are still around.
As the nights continue to grow longer, Snowshoe Hares are starting to molt into their white winter coats, shedding the brown fur they wore since spring. This seasonal change is probably triggered by photoperiod, and remains fairly constant for a location regardless of weather conditions. If all goes well, there will be snow on the ground by the time the Hares have turned mostly white, and their new coats will hide them from predators. However, as the climate continues to warm, the average duration of snow cover is decreasing. Unless this important prey animal is able to adapt quickly, climate models predict that Hares will stand out from the brown forest floor like “Eat Me” signs for increasing periods in spring and fall, with as yet unknown effects for the survival of the species.
Scientific Names of Species Mentioned
Elk – Cervus elaphus
Beargrass – Xerophyllum tenax
Chipmunk – Tamias amoenus, T. ruficaudus
Black Huckleberry – Vaccinium membranaceum
Whitebark Pine – Pinus albicaulis
Clark’s Nutcracker – Nucifraga columbiana
Red Squirrel – Tamiasciurus hudsonicus
Black Bear – Ursus americanus
Grizzly Bear – Ursus arctos horribilis
White Pine Blister Rust – Cronartium ribicola
Subalpine Fir – Abies lasiocarpa
Engelmann Spruce – Picea engelmannii
Mountain Pine Beetle – Dendroctonus ponderosae
Western Redcedar – Thuja plicata
Devil’s Club – Oplopanax horridus
Wild Sarsparilla – Aralia nudicaulis
Bracken Fern – Pteridium aquilinum
Paper Birch – Betula papyrifera
Black Cottonwood – Populus trichocarpa
Paper Birch – Betula papyrifera
Serviceberry – Amelanchier alnifolia
Fireweed – Chamerion angustifolium
Rocky Mountain Maple – Acer glabrum
False-azalea – Menziesia ferruginea
Yellow-rumped Warbler – Setophaga coronata
Nashville Warbler – Leiothlypis ruficapilla
Ruby-crowned Kinglet – Regulus calendula
Golden-crowned Kinglet – Regulus satrapa
Hermit Thrush – Catharus guttatus
Western Larch – Larix occidentalis
Mountain-ash – Sorbus scopulina, S. sitchensis
Moose – Alces alces
Blue Elderberry – Sambucus nigra ssp. cerulea
American Robin – Turdus migratorius
House Finch – Carpodacus mexicanus
Northern Flicker – Colaptes auratus
Aspen – Populus tremuloides
Varied Thrush – Ixoreus naevius
Snowshoe Hare – Lepus americanus
Retrieved March 20, 2015 from the Integrated Taxonomic Information System on-line database, http://www.itis.gov.References Arno, Stephen F. and Ramona P. Hammerly. 1977. Northwest Trees. Seattle: The Mountaineers. Best, Troy L. 1993. Tamias ruficaudus. Mammalian Species. 452:1-7. Dellinger, Rachel, Petra Bohall Wood, Peter W. Jones, and Therese M. Donovan. (2012). Hermit Thrush (Catharus guttatus). The Birds of North America Online (A. Poole, Ed.), Ithaca: Cornell Laboratory of Ornithology; Retrieved from the Birds of North America Online database: http://bna.birds.cornell.edu/ eBird. 2014. eBird: An online database of bird distribution and abundance [web application]. eBird, Cornell Lab of Ornithology, Ithaca, New York. Available: http://www.ebird.org. (Accessed: January 20, 2015). Elbroch, Mark, and Kurt Rinehart. 2011. Behavior of North American Mammals. New York: Houghton Mifflin Harcourt. Heinrich, Bernd. 2009. Summer World. New York: HarperCollins Publishers. Isacoff, Jonathan. 2010. “The Great Journey South.” Peak Experience, Vol. 6 Number 5, September/October 2010. Keane, Robert E.; Tomback, D.F.; Aubry, C.A.; Bower, A.D.; Campbell, E.M.; Cripps, C.L.; Jenkins, M.B.; Mahalovich, M.F.; Manning, M.; McKinney, S.T.; Murray, M.P.; Perkins, D.L.; Reinhart, D.P.; Ryan, C.; Schoettle, A.W.; Smith, C.M. 2012. A range-wide restoration strategy for whitebark pine (Pinus albicaulis). Gen. Tech. Rep. RMRS-GTR-279. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 108 p. Kershaw, Linda, Andy MacKinnon, and Jim Pojar. 1998. Plants of the Rocky Mountains. Edmonton, AB: Lone Pine Publishing. Miller, Jr., Orson K. 1979. Mushrooms of North America. New York: E.P. Dutton. Mills, L. Scott, Markete Zimova, Jared Oyler, Steven Running, John T. Abatzoglou, and Paul M. Lukacs. 2013. “Camouflage mismatch in seasonal coat color due to decreased snow duration.” Proceedings of the National Academy of Sciences 110:7360-7365. doi: 10.1073/pnas.1222724110. Patterson, Patricia A., Kenneth E. Neiman, and Jonalea R. Tonn. 1985. Field Guide to Forest Plants of Northern Idaho. Gen. Tech. Rep. INT-180. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. Swanson, David L., Ingold, James L., and Robert Galati. (2012). Golden-crowned Kinglet (Regulus satrapa). The Birds of North America Online (A. Poole, Ed.), Ithaca, Cornell Laboratory of Ornithology; Retrieved from the Birds of North America Online database: http://bna.birds.cornell.edu/ U.S. Fish and Wildlife Service. 2014. “Whitebark Pine.” Accessed November 26. http://www.fws.gov/mountain-prairie/species/plants/whitebarkpine/. Whitaker, John O., Jr. 1980. National Audubon Society Field Guide to North American Mammals. New York: Chanticleer Press, Inc. Zimova, Marketa, L. Scott Mills, Paul M. Lukacs, and Michael S. Mitchell. 2014. “Snowshoe hares display limited phenotypic plasticity to mismatch in seasonal camouflage.” Proc. R. Soc. B. 281:20140029. doi: 10.1098/rspb.2014.0029.