Wilson's WA

Observers: Donna Willey
Email: basina@verizon.net
Date: 05/25/2008
Time: 10:06 PM -0400

Wilsonia pusilla otherwise known as Wilson’s warbler comes in 3 races: W.p. pusilla, W.p. pileolata, and W.p. chryseola. I believe that the photos I enclose show the race chryseola. In the PRBO data, chryseola is said to breed west of the Sierra crest and west of the Cascades in WA state. The race W.p. pieolata breeds in the Warner and White mountains of central eastern CA (A.O.U., 1957). Dunn & Garrett (1997) suggest that the boundaries of chryseola and pileolata in eastern CA “need clarification.” According to Dunn and Garrett (1997) the Western montane populations of chryseola and pileolata are found in willow and alder thickets at or near treeline and also in montane meadows. I found abundant numbers of Wilson Warblers in wet meadows and near seeps and marshes and the stream that runs through this particular riparian habitat. The race pusilla is found on the east coast and only as a vagrant in the west. As far as appearance, the race chryseola is the brightest yellow of the 3 races and the forehead and lores are a yellow-orange in many males. This is what I saw in the large flock that spent several weeks in the Convict creek drainage area above Crowley Lake. This area, below the green church at Benton Crossing, is a sage, willow, alder, dwarf birch and aspen riparian habitat. Near the creek the willow are large, old, and numerous interspersed with alder, dwarf birch and aspen trees. (Although the aspen grow in meadows and are not numerous.) The willows, alder and birch create a very dense understory. The Wilson’s chryseola have an almost bright yellow-orange forehead in the adult males. One can see this coloration in some of the photos. David Gaines (1988) in his wonderful book, Birds of Yosemite and the East Slope, experienced the Wilson’s warbler in probably the same manner as did I. He states: “While one of our scarcer nesting birds, Wilson Warbler’s are common transients. Large flights pass east of the crest in early May, and through montane meadows in August. At times, these restless little birds flash like golden threads in every shrub and thicket.” The day I took the photos it was a cloudy and overcast day with a strong wind blowing. The warblers I was seeking had been foraging in the tops of aspen trees that were just in the process of leafing out. With the wind blowing strongly there wasn’t a warbler to be seen. As I walked downstream toward the lake I stopped and peaked through the large willow bushes, still without leaves, which lined the creek. I was amazed to see, like rays of sunlight in the gloom, small darting yellow birds landing on the branches overhanging the creek looking for insects and moving on to their next perch. I crawled onto the bank of the creek with my camera and lay on the ground. Here there was no wind blowing, all was calm and quiet; after I settled in and waited a few minutes warbler after warbler joined me until I had counted over 100 of the little birds, both male and female. I started taking photos the birds didn’t seem to mind my presence and were very inquisitive about the click of the camera and at times would land within several feet of me or closer looking for the unusual noise that my camera made. The next day I returned to the same spot, however, all was quiet, my vibrant yellow birds had moved on.