Blue-gray rosette lichen

Small lobed foliose lichen. Capable of growing at a multitude of angles on a variety of surfaces, Physcia caesia also tolerates a wide range of environmental extremes from the high temperatures of desert locations to the low temperatures of the Antarctic. It grows on both dry stone and that moistened by seepage, and can survive being irregularly submerged for extended periods underwater. Like many lichens that grow on rock, Physcia caesia is able to extract nutrients from the substrate upon which it grows, as well as from rainwater and atmospheric dust. It also is known to grow well near bird perches. Maybe a connection?