Hello Eric,


Here is some related research information:



Jennifer A. Clarke
Richard E. Johnson " The Influence of Spring Snow Depth on White-Tailed Ptarmigan Breeding Success in the Sierra Nevada (DJVU format)
(Condor: Vol. 94, No. 3, May-June, 1992)
"The relationship between spring snow depth and breeding success of an introducedpopulation of White-tailed Ptarmigan (Lagopus leucurus altipetens) in the SierraNevada, California, was studied from 1982 through 1987. Yearly spring snow depth variedfrom 50.8 cm to 424.2 cm. Hatch dates were later in years of deep snow (P less than 0.05) butbrood size showed no relation to snow depth. Nesting success, chick survival, and broodsuccess (all of which contribute to breeding success) were negatively correlated with snowdepth as was breeding success (P less than 0.05). The number of paired ptarmigan in the studyarea varied from 22 (in 1987) to 46 in 1985 which was the year with the least snow; however,no significant relationship existed between breeding numbers and snow depth. Successfulreproduction of White-tailed Ptarmigan in the Sierra Nevada appears to be strongly affectedby snow, potentially due to its influence on the availability of resources such as nest sites,food, and cov!
er."



Dan Reiff
Mercer Island ----- Original Message -----
From: "Eric Kowalczyk" <aceros at mindspring.com>
To: "tweeters" <tweeters at u.washington.edu>
Sent: Sunday, September 4, 2011 9:43:47 AM
Subject: [Tweeters] white-tailed ptarmigans at Rainier


For 2011, what were the earliest reports of ptarmigans with young chicks at Rainier? Seems that they were postings on Tweeters in late July/early August. With such a heavy snowfall this winter, .if incubation is ~23 days and let's say the chicks seen were ~one week old...that would put beginning incubation sometime around late June. I guess there must be some small patches that are snow free in late June???????

does anybody know anything about when these guys begin nesting up at Sunrise and Paradise? And where? I would suspect that their nesting habits are dependent on the variations of snow levels from year to year. Do they nest at the lowest "above timberline" elevations that would become first available? Amazing little birds when you think about it!


Eric Kowalczyk
Seattle


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