[Originally appeared in the Sierra Wave newsletter, Vol. 25, No. 2, Nov-Dec 2006 – click here for original with photos]
When most people think of fall, visions of falling multicolored leaves, the World Series or football come to mind. Conversely, when birders think of fall they have visions of vagrants (unexpected species) dancing in their heads.
The calendar concept of fall has little to do with fall for birds and birders. Fall begins in early June when the first female Wilsons Phalaropes arrive from their northern breeding grounds. The females lay their eggs and then depart leaving the domestic duties to the males as they head for the high Andean lakes of South America. By late June the first Rufous Hummingbirds return to Inyo from as far north as Alaska. For some species (e.g., shorebirds) the adults depart the northern tundra before the young who make their way without help and reach the wintering grounds on their own. Fall migration can extend into December with a few birds lingering into January. This is especially true for some ducks, such as White-winged Scoters and Barrows Goldeneyes, who visit for a time, then continue their southward journey.
Each species has a window or period of time during which they are expected to occur here. For some species it is very short, perhaps less than two weeks, while others move through during a two- to three-month span. The Connecticut Warbler, not surprising based on its name, is an eastern and northern species that is a vagrant to Inyo County. All five records are between 20 September and 1 October for one of the briefest windows for a bird occurring that often. Most migrants pass through quickly in spring and more leisurely in fall, often taking three months or more to reach their wintering grounds in southern California, South America or points in between.
The finding of an unexpected species is cause for a great deal of excitement among the birding community. The resulting behavior cannot be explained to nor understood by a non-birder but it requires no apology or accounting to compatriots. Vagrant fever has many bizarre side effects causing the afflicted to drive all night through rain and snow or fly a red-eye special to reach the location where a vagrant was reputed to be the previous day. The more rare the species, the more bizarre the behavior. There is no known cure nor is anybody working to find one. One could say that migrating birds often cause birders to migrate with them!
Wood Thrush, Photo by Jim Pike