Apparent Predation by Rock Wren of Common Sagebrush Lizard

analyses of the stomach contents of wrens (Troglodytidae) rarely report verte- brates (Beal et al. 1916, Bent 1948, Poulin et al. 2001, lopes et al. 2005), and few published records exist of wrens capturing and consuming vertebrate prey. We report here on a rock Wren ( Salpinctes obsoletus ) that was seen apparently preying upon a Common Sagebrush lizard ( Sceloporus graciosus ). The observation occurred on 11 June 2015 during the Western Field Ornithologists convention held in Billings, Montana, on a field trip Casey led to Bear Canyon. Bear Canyon is located in Carbon County on the south side of the Pryor Mountains in south-central Montana at the northern edge of the Wyoming Basin Ecoregion near the Montana/Wyoming border (Marks et al. 2016). This arid canyon is bounded by outcropped limestone and sup-ports a dominant vegetation of utah Juniper ( Juniperus osteosperma ), limber Pine ( Pinus flexilis ), and Big Sagebrush ( Artemisia tridentata ). at about 10:00 MDT, while surveying a brushy and rubble-filled draw (45.0777° N, 108.5393° W; 1580 m elevation), we found a rock Wren already grasping in its bill a small lizard by the neck (Figure 1). We watched and photographed the bird from a distance of approximately 10 m for at least 60 seconds. During that time the wren acted alert to our presence but nevertheless stayed in one location in full view of the group. The wren twice struck the lizard on a rock, as if to kill it, although we saw no movement by the lizard during our observation. after this brief period the wren moved out of our view and was not seen again. From the wren’s behavior and the fresh body condition of the lizard, we assume that it captured the lizard alive