Discussion
The pikas on Mt. Shasta occur in
several, sometimes widely scattered, localities. In my visits to
the sites I occasionally hear or see more than one pika. It is
known that Ochotona princeps
lives solitary in territories, often alternating male and female.
Still, they do not seem to be numerous. Perhaps most amazing is the
fact that I could find pikas in the original localities described in
1898. Over one hundred years later and the pikas have survived in the
same talus slopes. It is also amazing that pikas are living as low as
4,500' in lava on the north side of the mountain. These environments
are hot in the summer daytime, but have deep fissures that are cool. It
is to be noted that the glaciers on Mt. Shasta (though variable
throughout the years) were thought to be growing, but since the early
21st century are now known to be shrinking.
Although this study found pikas in virutally all the historic pika
sites, a continued trend of warming is expected to force both pikas and
plants upslope, most likely with challenging effects.
There are problems studying the moment-in-time distribution of pika
populations and the inference of population trends. Specificaly, the
discovery, occupation and abadonment of sites, the duration of
occupancy and interactions with predators and non-biological stresses
all would need to be much better understood to be confident in such an
analysis. At this point in time, 2020, it would seem that the pika
populations on Mount Shasta are numerous and widely scattered over the
south-west and west side of the mountain and are in no danger of
extirpation.
I have heard pikas calling and giving response several times
during my investigations, but the pikas on Mt. Shasta are, as
noticed in 1898, much less noisy than their nearby cousins. I have
hunted for and found pikas in the Lava Beds National Monument, Mt.
Lassen National Park and in Yosemite, and in all cases, the pikas
were rather noisy during my visit--at least as compared to those on
Mt. Shasta. Another curious note: I haven't found a "haystack"
which is so typical of the species. This rarity of haystacks was
also noted in the 1898 report. I can only assume that at least
some of their haystacks are underground and the others are just
not being noticed. Although I generally am not looking for
haystacks, in other places the presence of a haystack is the first
sign that pikas are around and they seem curiously absent.
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