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Other past observations have bearing on this sheep group. For decades, males from the Mount Baxter herd have been known to use the 60 Lakes and Gardiner Basins in summer, including Mount Gardiner. In September of 1999, John Wehausen investigated a report of thirteen sheep in the Gardiner Basin because it was notably more than the number of rams he expected there. Much to his surprise, we found clear evidence of lambs, thus also females, neither of which had ever been known to use areas on the west side of the Rae Lakes drainage. Later that same month in 1999 he had the chance luck of meeting the hiker who had seen the group of 13 sheep, and she verified that it included everything from lambs to big rams.
Similar to the pattern of males using the 60 Lakes and Gardiner Basins, adult females and associated younger sheep had used the area immediately north of Onion Valley and Kearsarge Pass from Kearsarge Peak to Mount Gould in summer since at least the early 1970s. Beginning in the 1990s, after this herd began avoiding low elevation winter ranges, they were documented to live in this area year round. However, in the second half of the 1990s this changed and by 1997 we could no longer find evidence of females still using this area during any season. Thereafter, what little sign of sheep use that could be found there suggested males, and this was verified in the laboratory from droppings collected in 1998 and 2001. Together, all this information suggests that around 1996 the female group that lived in the Kearsarge Peak area moved west and took up residence around Mount Gardiner. Perhaps this occurred first during some mild winters, and when they discovered that they could drop west down to the cliffs above Bubbs Creek to get out of snow in winter they abandoned their old ranger east of the Sierra crest. These sheep will be monitored as best possible in coming seasons and years.
Colonization of new habitat by bighorn sheep is a relatively rare event. This is why the primary tool for restoration of this species involves catching sheep and moving them to locations where they once existed. Colonization obviously must occur and did occur; it is what got these animals to where they were when Europeans appeared. But, given its rarity, it is a privilege to document this new ranger expansion. Hopefully, further such natural expansions will be discovered in the future.
See also Sierra
Nevada Bighorn Sheep: a Brief History
by John Wehausen
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