squeaky sound not unlike that of a crow. This call greatly differs from that of much deeper and more dramatic northern potoo. Distribution and habitat The nominate subspecies of the common potoo is found in Trinidad & Tobago and every mainland South American country except Chile, though it has been recorded in that country as a vagrant. There it ranges from the Andes to the Atlantic Ocean. N. g. panamensis is found from eastern Nicaragua south through Costa Rica and Panama and west of the Andes from northwestern Venezuela through Colombia and Ecuador into northwestern Peru. The common potoo is a resident breeder in open woodlands and savannah. It avoids cooler montane regions; it is rarely observed over 1,900 m above mean sea level even in the hottest parts of its range. It tends to avoid arid regions, but was recorded in the dry Caribbean plain of Colombia in April 1999. It has many populations in the gallery forest-type environment around the Uruguayan-Brazilian border. A bit further south, where the amount of wood-versus grassland is somewhat lower, it is decidedly rare, and due west, in the Entre Ríos Province of Argentina with its abundant riparian forest, it is likewise not common. The birds at the southern end of their range may migrate short distances northwards in winter. Behavior and ecology Cryptic behavior The common potoo seeks to mimic the perch on which it rests, using a technique called masquerading. Adult and juvenile potoos alike choose perches that are similar in diameter to their own bodies, so that they can better blend in with the stump. Most potoos choose stumps and other natural materials on which to rest, but some adults have been spotted perching on man-made items. These birds adjust their perching angle to best mimic the stump where they are. The potoo sits with its eyes open and its bill horizontal while awake, but if disturbed, assumes an alert “freezing” posture (flexibility). This entails sticking its beak vertically up in the air, closing its eyelids (through which it can still see via slits), and remaining still. If disturbed by larger animals, such as common marmosets (Callithrix jacchus), it may break its camouflage and try to chase the threat away. If disturbed by a human being, its behaviors can be quite variable - quickly flying away, intimidation via beak-opening, or remaining still even when being touched. Feeding This nocturnal insectivore