Terry's Tidbits

October 15, 2009

Preparing for Winter

Autumn comes early to the high Rockies. As early as August, plants and animals begin to prepare in various ways for the coming cold, snow, and high winds of winter. In essence, organisms can either settle in for the winter or flee to warmer climes, and if they stay, they can either sleep the winter away or stay active.

a photo of a pika
Pikas store grass for winter snacks.

Photo courtesy of Rocky Mountain National Park

The pika (Ochotona princeps), for example, spends a busy winter under the deep snow above treeline eating “haystacks” of grasses that it harvests during the brief summer.
a photo of a marmot
Marmots sleep all winter

Photo courtesy of Rocky Mountain National Park

The yellow-bellied marmot (Marmota flaviventris), on the other hand, drifts into a true hibernation, during which it can lose up to half its body weight. In late summer, marmots begin storing fat. They hibernate from September or October into April or May.
Animals don’t always survive hibernation. Recent research shows that mammals that eat human handouts during the summer are less likely to survive hibernation because the quality of fat stored is not as high as that on a natural diet. Another good reason to not feed the animals!
a photo of a spruce tree
Conifers retain their needles.

Photo courtesy of and copyrighted by Ernie Bernard

Among trees, the conifers (spruce, fir, pine, and Douglas-fir) retain their leaves, which remain green throughout the winter, but much of the plants’ summer activity is shut down or decreased. Photosynthesis stops except for uncommonly warm, sunny days. Intricate molecular changes allow these species to keep photosynthesis in a “dormant” state but geared up and ready. If conditions permit, photosynthesis and other functions can be started up quickly to take advantage of the favorable state of affairs.
a photo of aspen leaves in the fall
Aspen leaves fall in autumn.

Photo courtesy of and copyrighted by Ernie Bernard.

The broad-leaved trees, however, drop their leaves - usually after a brilliant show of fall color - and become dormant until longer spring days waken them to start producing leaves – their photosynthetic organs.
a photo of a mountain chickadee
In winter mountain chickadees move to lower altitudes.

Photo courtesy of Rocky Mountain National Park

Birds have mobility that the earthbound can only envy. But, while many species flee to warmer climates, some remain and do well either by finding a niche in the cold or by migrating down to nearby parks, fields, and lawns as the weather changes. The mountain chickadee (Poecile gambeli) for example, spends the winter in the park or in nearby lowlands.
a photo of a hummingbird
Broad-tailed hummingbirds fly south.

Photo courtesy of Rocky Mountain National Park

At the other extreme, the broad-tailed hummingbird (Selasphorus platycercus ) migrates to Mexico and Central America before returning in spring.

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a photo of an Elk Bugle Corps volunteer assisting a visitor
Elk Bugle Corps volunteers keep visitors from approaching the elk.

Photo courtesy of Rocky Mountain National park

September 30, 2009

The Elk Bugle Corps

Rocky Mountain National Park gets a huge influx of visitors during the elk mating season, also known as the rut. Elk are commonly seen in the park's meadows during the evenings, and visitors flock to observe them. So the park calls on the Elk Bugle Corps volunteers.

a photo of the an elk jam
Elk Bugle Corps members try to prevent traffic jams.

Photo courtesy of Rocky Mountain National Park

The Elk Bugle Corps started in 1990. Each fall, about 90 volunteers give 2200 hours to the park. Every night during the rut, they go out in the park and talk with visitors who are observing the elk. They also help prevent traffic jams, a common occurrence on fall evenings. Sometimes visitors need a reminder that elk are wild animals, best observed from the road. The presence of the Elk Bugle Corps keeps visitors safe.

a photo of an Elk Bugle Corps volunteer instructing a visitor
Elk Bugle Corps volunteers teach visitors about the rut.

Photo courtesy of Rocky Mountain National Park

The volunteers also teach visitors about elk ecology. When bus tours are offered, Corps members narrate the talks. They also give formal programs at the amphitheater in Moraine Park. And of course they have informal conversations with roadside visitors.


So, when you come to the park this fall, give a salute to the Elk Bugle Corps volunteers. Want to join next year? Better contact the volunteer office now. It is a very popular job.

For more information on the elk rut, click here.

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a photo of fading aspen leaves
Aspen leaves are fading from green to gold now in Rocky Mountain National Park.

Photo courtesy of Rocky Mountain National Park

September 16, 2009

Green Fades to Gold

Unusually mild weather and an abundance of rain may slow the color change in aspen in the lowest elevations of Rocky Mountain National Park.

a photo of leaves in fall colors
Aspen leaves turn golden in the fall due to their carotene accessory pigments while Fremont geranium leaves have turned red because of their anthocyanin accessory pigments.

Photo Courtesy of Rocky Mountain National Park

What causes this shift of colors as the weather cools and days shorten? Chlorophyll is the green pigment responsible for the green color in plants and for most of the photosynthesis or food production in plants. As temperatures cool at night, plants start to break down chlorophyll and pull its building blocks back into the trunks and roots, conserving these vital resources for the future. However, other "accessory" pigments in the leaves are not broken down and stored. Accessory pigments are masked by chlorophyll in spring and summer, but remain to color the leaves in the fall. In aspen, the main accessory pigments are yellow and orange carotenes - the family of pigments that give carrots their distinctive orange color. In other plants such as wild geraniums, anthocyanins - red pigments - function as accessory pigments and provide the distinctive red fall colors. Accessory pigments capture light from other parts of the spectrum than that captured by chlorophyll, and thus make plants more efficient at making their food.

a photo of a hillside of aspen trees in the fall
Aspen clones above Bear Lake are easily distinguishable in fall because they change colors at different rates.

Photo Courtesy of Rocky Mountain National Park

You may wonder why the aspen trees you see in suburban yards seem to turn colors independent of one another, while whole clumps of aspens in the park seem to turn color at once, while other clumps turn earlier or later. In suburban yards, each aspen tree is usually an independent plant put in place by the home owner. Aspens in the wild reproduce by sending out underground shoots more often than by seed. These shoots eventually pop up some distance away from the original aspen tree that produced them. This forms something we think of as a separate tree, but in fact, they are just stems of one plant. All these connected aspen stems, known more accurately as a clone, turn color and lose leaves in the fall in unison because they are one plant.


The brief and brilliant season of fall is caused by processes as varied as its vibrant colors.

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September 2, 2009

Clouds and Fog

In Rocky Mountain National Park, a change of weather can be just a short walk away – which is why it’s so important to be prepared for any kind of weather. Just as boulders in a stream direct the flow of water over and around, so mountains direct air masses.

a photo of large cumulus clouds
Cumulus clouds

NPS Photo

When air is forced up and over a mountain ridge, it cools. Cool air holds less moisture than warm air, resulting in cloud formation. If the air is unstable, we’ll see large, puffy cumulus clouds form as the air rises – or even a thunderstorm.

a photo of lenticular clouds
Lenticular Clouds

NPS Photo

If the air is stable and the wind flow is strong, we’ll see lenticular clouds – also called lens clouds, cap clouds, or “flying saucer” clouds. These wonderfully unique clouds are common along the eastern slopes of the Rockies, especially in the wintertime when high winds aloft crest the continental divide and then sweep outwards towards the plains. Unlike other clouds that are blown along by the wind, lenticular clouds do not move because they form as the air rises and dissolve as it descends in the "bounce."

a photo of fog over Mt Chiquita
Fog on Mt. Chapin

NPS Photo

Differences in the heating and cooling of mountain slopes also affect cloud formation. Solar radiation increases with altitude (which is why sunscreen is so important when you hike in the mountains). Surfaces exposed to the sun rapidly heat up, and those not exposed stay cool. This can result in dramatic difference between sun and shade. In some areas the difference may be as great as 40 -50°F. On sunny days, upslope air flows develop due to this differential heating. These rising plumes of air are especially noticeable in the summertime and are responsible for our afternoon thundershowers. At night, the mountains cool quickly because of the thin, dry air. The cool air descends the slopes forming drainage flows that accumulate in valleys. If moisture is present, this cool, sinking air can cause local night-time valley fog.

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a photo of ems and rangers at work
Rangers and paramedics treat countless visitors for AMS every year. Many people go untreated.

August 12, 2009

Acute Mountain Sickness

Every year, rangers in Rocky Mountain National Park treat countless park visitors with headaches, nausea, dizziness, and a host of other ailments. Many of the people they are treating are suffering from Acute Mountain Sickness (AMS), a generic label applied to symptoms commonly experienced by people visiting high altitudes. The people treated by the rangers aren’t all rock climbers and mountaineers. Many of them are simply enjoying an easy hike or leisurely drive through the park with their family or friends. When travelling above 8,000 feet, everyone is susceptible to AMS.

a photo of Rock Cut on Trail Ridge Road
AMS is not just a mountaineer's ailment. Anyone who comes to high elevations can get it.

As a person ascends through the atmosphere, every breath contains fewer and fewer molecules of oxygen. The body’s efforts to compensate for the reduced atmospheric pressure and a lower concentration of oxygen result in the symptoms associated with AMS. In order to avoid worsening symptoms, learn to recognize early signs of AMS.

Symptoms of mild AMS include mild headaches, increased breathing, rapid pulse, nausea, loss of appetite, lack of energy, and general malaise. These are warning signs not to go any higher than you already are.

A person suffering from moderate AMS may begin vomiting, experiencing increased shortness of breath and a headache that doesn’t respond to typical pain relievers. If you or someone you are travelling with experience these symptoms, it is important to descend to lower elevations immediately. Spend at least a day at an elevation where you are comfortable before attempting to ascend again.

If symptoms advance to a lack of balance or coordination, slurring of words, altered mental state, extreme shortness of breathe, a wet or rasping cough, or blue skin, the person may be experiencing severe AMS and their life may be in jeopardy. Go down immediately and seek medical attention.

a photo of a person drinking water
If you're thirsty, you're already dehydrated. Drinking plenty of water can reduce symptoms of AMS
The easiest way to treat AMS is to prevent it. Remember these simple rules when travelling to altitude. When travelling to high altitude (above 10,000 feet), it is wise to spend at least one night at a moderate elevation before ascending. Climb as high as you like during the day but never spend the night more than 1,000 feet higher than the night before. Remember that if you’re thirsty, you’re already dehydrated. Drink water often. Never take a headache with you when ascending. Treat the headache before going any higher. If you can’t treat it, you’re already too high.
a photo of Alpine Visitor Center
The Alpine Visitor Center is the highest facility of its kind in the National Park Service. Rangers here are well acquainted with AMS.

High elevation travelers with preexisting medical conditions are in even greater danger. Conditions such as high blood pressure, diabetes, and conditions affecting the brain, heart, and lungs are among those that may be aggravated by high altitude and can prove deadly in the mountains.

Fortunately, AMS is extremely easy to treat if diagnosed in time. The most effective treatment is simply to GO DOWN.


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Welcome to “Terry’s Tidbits!”

This blog will provide a bit of information and some attractive pictures about a natural history topic, an answer to the "burning question of the week," or an event in the park.

The original Weekly Tidbits were created by Terry, a former Resource Management Supervisor (now retired) at Rocky and members of her staff. This blog will provide a new home for these delightful short articles.

We have specifically tried to size some of the more attractive large photos to be made into wallpaper for your computer screen (by right clicking on the picture and selecting "Save as wallpaper" or "Select as background"). As a result, we hope you find these Tidbits informative and useful.

Come join us.

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Last updated: February 24, 2015

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1000 US Hwy 36
Estes Park , CO 80517


970 586-1206
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