Dr. Jay Carlisle, Idaho Bird Observatory and Dr. Alfred Dufty
Long term projects like the Idaho Bird Observatory’s Lucky Peak banding station provide valuable information on bird conservation and life history traits. We explored banding data from 1997-2009 to examine yearly patterns of abundance and survivorship for the 10 most common breeding species. We found that survivorship patterns vary by species. We documented Nashville and Yellow warblers living up to 4 years, while some Dusky Flycatchers, MacGillivray’s Warblers and Chipping Sparrows lived 7 years or more. In fact several Western Tanagers and Dusky Flycatchers exceed or match longevity records in the USGS Bird Banding Lab database. The ratio of hatch year birds (hatched that spring) to adults lends insight into survivorship, productivity and recruitment in the community. Species may have low numbers of hatch years one year yet high numbers of second year birds (hatched the previous spring) the next year. This was particularly seen in Warbling Vireos and suggests that immigration is important for this species. In contrast, the number of hatch year Spotted Towhees in one year correlated with the number of second years in the next year, implying that many towhees hatched at the site return to breed. Analysis also showed trends in population dynamics and striking annual difference in species’ abundance. Neotropical migrants like MacGillivray's and Yellow warblers peaked in both 2000/01 and 2006/07 but Nashville Warblers (another Neotropical species) peaked in 2005. Interestingly, short distant migrants such as Chipping Sparrow and Spotted Towhee also peaked in 2005. Further investigation is required to determine which factors—possibly including weather, diet, timing of breeding and migration strategy—contribute to these fluctuations.