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Wildlife and Other Sightings: Sooty Grouse and the Alpine Mammal Survey

August 25, 2012 Posted by: BW - Mather District Volunteer Interpretive Ranger

Sooty Grouse
Dendragapus fuliginosus

Sooty Grouse  Sooty Grouse

August 7, 2012

A Sooty Grouse was spotted in the backcountry of Yosemite this week. Using their camouflaged plumage, these year-round residents of Yosemite spend most of their time on the ground where they blend in perfectly with the lodgepole pine forest of the high country. As you unknowingly approach them hiding in the underbrush, they will wait until the last possible moment before taking off with a loud rush of flapping wings. Hikers may have heard the male during nesting season (May through June) issuing a deep, repetitive call that is very hard to locate. Inflated neck sacs covered by bare yellow skin act as resonators to help the call travel more than a quarter mile.

Alpine Mammal Survey
Marmot  Pika

Belding ground squirrel  Golden-mantled ground squirrel

July and August

This is the fourth year that park researchers have been surveying the distribution of alpine mammals in Yosemite National Park. This survey is part of a cooperative effort between the USGS, NPS, and six other government agencies and universities. The primary goal of the study is to model the range shifts of these mammals that may result from the climactically driven transition of alpine meadows to woody dominated communities in the Sierra Nevada mountain range. The population distributions of the Yellow-bellied marmot (Marmota flaviventris), pika (Ochotona princeps), Belding's ground squirrel (Spermophilus beldingi), and golden-mantled ground squirrel (Spermophilus lateralis) are being surveyed at five locations throughout Yosemite. The survey locations are all above 8,000 feet in elevation and represent the northern, central, and southern parts of Yosemite.  

The two techniques used during the survey are transect line counts and point counts. The transect line is a 10 km (6.2 mile) section of trail that a researcher walks slowly. He or she travels along the line being as observant as possible and recording any individuals of the target species that can be identified by sight or by sound. Along that line there are ten randomly chosen points and a researcher stops at each point to record any individuals of the target species that are observed in a span of 15 minutes.  When the researcher records the distance to the target species, along with other details about the observation, the data can be analyzed to get a good estimate of the target species populations.    

Table 1.  Average Number of Mammals Counted During Transect Line Counts*
Location Marmot Golden-mantled

ground squirrel


ground squirrel

Buena Vista Peak
21 13 0 4
Kerrick Meadow
14 10 17 1
Chain Lakes
14 7 0 2
Red Peak Pass
10 4 0 38

*includes data from two samples of the transect line, rounded up to the nearest whole number.

Table 2.  Average Number of Mammals Counted During Point Counts*

Location Marmot Golden-mantled

ground squirrel


ground squirrel

Buena Vista Peak
6 1 0 4
Kerrick Meadow
5 5 11 0
Chain Lakes
6 4 0 1
Red Peak Pass
1 2 0 22

*includes data from two samples of the transect line, rounded up to the nearest whole number.


3 Comments Comments Icon

  1. Alan Beverly - Santa Cruz, CA
    September 19, 2012 at 09:41

    Spotted 2 sooty grouse at Sunrise Lakes Yosemite 9-19-12

  2. Yosemite National Park
    September 05, 2012 at 03:19

    Specific to Yosemite, the white-tailed ptarmigan is a less common non-native introduced game bird that is resident in the park and is found at the higher elevations, generally above 9,000 ft. Parker Pass is a perfectly reasonable and expected location for this species. The sooty grouse is a fairly common native species, and is tied to more coniferous habitat between 5,000-8,000 ft, as opposed to characteristically more open subalpine habitat for the ptarmigan.

  3. Steve - Boulder Creek, CA
    September 03, 2012 at 04:51

    I saw closely a covey of what I identified as Ptarmigan in the valley at the far side of Parker Pass. What exactly is the difference between "Sooty Grouse" and Ptarmigan?


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Did You Know?

Tuolumne River

In 1984, 83 miles of the Tuolumne River were added to the Wild and Scenic Rivers System by Congress with an amendment to the Wild and Scenic Rivers Act. This included 54 miles of the river within Yosemite National Park.