[All photographs copyright, Gary Nunn 2013] – After hearing reports of abundant Lucy’s Warbler returning this spring to the deserts of Arizona, I decided to search through the Borrego Valley “Sink” mesquite bosque for this species. Although more common further east, this is the only known breeding locale for Lucy’s Warbler in San Diego County and a tenuous one at that. With usually only a handful of pairs in a 2500 acre habitat the search could be lengthy! Looking at previous year’s arrival dates into the Borrego Sink it seemed reasonable they could be around by this time although I had heard no reports thus far this spring. I set off at 6:45 am, just before dawn, from the north terminus of Yaqui Pass Road and headed northeast into the pitiful looking mesquite bosque. There were some early morning clouds and I thought it might stay cool for a while. About 0.5 miles in, at exactly 7:00 am, a singing Crissal Thrasher Toxostoma crissale was a nice find, another specialty species of the area.
The only other birds to materialize from the mesquite bosque were Black-tailed Gnatcatchers, Black-throated Sparrows, Verdin, and Bewick’s Wrens, the last species seemed to be following me everywhere. Also a few flyover species including Lawrence’s Goldfinches making their twinkly flight call. Unfortunately the clouds cleared quickly and it started warming up. After continuing northeast, and zig-zagging around all over the place, I decided to pack it in and turned south to walk to the perimeter dirt road. Just then I happened on a male Lucy’s Warbler Oreothlypis luciae singing loudly from a mesquite tree.
The mesquites everywhere were leafless and this was one of only a handful that I found that was getting into leaf. I estimate it was about a mile in from the parked car, time was 8:39 am. Moving around a small territory, the Lucy’s Warbler continued singing for about five minutes before taking a longer flight north over the mesquites and out of sight. The mercury was rising fast so I headed back to the car via the south perimeter dirt road. An example of the song, identical to the bird seen and heard, can be listened to at the Xeno-Canto link below.