Animal use at Pika haypiles highlight biodiversity in Bodie Hills

Bodie Hills highlight in Words of the Wild | Sierra Club Newsletter
December 14, 2020
Winter Exploration 2021
March 4, 2021

Animal use at Pika haypiles highlights biodiversity in Bodie Hills


The Bodie Hills encompass a vast area of land between the Eastern Sierra Nevada and the western side of the Great Basin in California. This intermediate ecological zone lends itself to being one of the most biodiverse areas in the Great Basin. Understandably, many environmental, geological, ecological, and other scientific research have been conducted in this living laboratory. A new study on the American pika (Ochotona Princeps) is in press at the Western North American Naturalist journal. Pikas depend on broken rocky slopes for habitat. In the Bodie Hills, native habitat, as well as ore dumps that mimic the talus slopes, have long supported pikas. The Bodie Hills are the site of the longest-running pika study in history, started in the 1960s by island biogeographer and pika pioneering scientist, Andrew Smith (emeritus professor, Arizona State University).

Local USFS scientist emerita and long-time pika researcher, Constance Millar, teamed up with expert camera trapper, Kenneth Hickman, to document pikas via camera traps in the Bodie Hills and surrounding areas. They photographed 26 of the 30 documented mammal species of the area and 10 bird species. The cameras were set near pika haypiles (caches of food) over the span of five years. In addition to documenting previously unobserved pika behaviors, the cameras documented 16 sympatric herbivores (similar and competitive species) and seven pika predators (carnivores), providing insight into the recent decline of pika populations in the Bodie Hills. These data further verify the abundance of biodiversity in this transitional landscape of the Sierra Nevada and interior Great Basin.

While capturing photo evidence of behaviors and interactions, the study simultaneously measured subsurface temperatures of the talus fields that he pikas call their home. Commonly pikas are found in high elevation mountainous regions, and interestingly are rather ill-equipped to survive temperatures above 78℉ but nonetheless are found among the warm taluses and ore dumps of the Bodie Hills. Although the ambient air temperature may reach scorching degrees, especially in mid-summer, the pikas can retreat deep within the network of boulders where temperatures were regularly measured to be 16℃ cooler than the surface. With nature’s air-conditioning the talus fields provide an ideal habitat, cool and safe. However, with climate change come new predators and competitive species as habitats dwindle and temperatures rise.

Because of poor thermoregulation, low body temperatures, low reproductive rates, non-hibernating lifestyle, and dwindling habitat, pikas are particularly affected by climate change, and as such have been labeled the harbingers of threat for other species. The camera traps set in this study provide “valuable and inexpensive, simple approaches for wildlife studies and particularly small mammals at potential risk from changing climates” (Millar and Hickman, in press). The study provides new information and techniques to the library of data regarding small mammals and the impacts of climate change in the Bodie Hills. However, questions remain and research will continue to shed light on this species and the diversity of animals inhabiting the Bodie Hills.  Millar’s future work will involve an inventory of all potential pika habitat in the Bodie Hills to determine if and when that habitat was occupied. This will help the overall understanding of the impacts of climate change and the extent to which the Bodie Hills provides climate refugia for species adapting to a warming Sierra and Great Basin.


Manuscript Citation: Millar, Constance I.; Hickman, Kenneth T. In press. Camera traps provide insights into American pika site occupancy, behavior, thermal relations, and associated wildlife. Western North American Naturalist.

Photo Archive Citation: Hickman, Kenneth T.; Millar, Constance I. 2020. Camera trap photographs from American pika haypiles in California. Fort Collins, CO: Forest Service Research Data Archive.


Below are some photo highlights that are sure to make you smile captured by Millar and Hickman’s trail cameras–reprinted from the Forest Service Research Data Archive cited above.

Above: Yellow Bellied Marmot

Above: Gray Fox

Above: “Get my good side.”

Above: Bobcat

Above: Mountain Cottontail selfie

Above: Short-tailed Weasel

Above: Long-eared bat

Above: Pika at haypile

1 Comment

  1. Steve Klukkert says:

    I was a student at Berkeley when Ms. Millar was getting her doctorate.
    One graduate seminar I took had a habitat model assignment and I chose pika at Sagehen Station.
    These photos and habitat adaptation studies are classics.

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