THE SURVEY POSTURE IN WALL LIZARDS, PODARCIS-MURALIS

Male, female and juvenile wall lizards (Podarcis muralis) observed liv ing on a high, southfacing brick wall in April and August were sometim es (4% of total observation time in adult males) seen immobile, facing downwards in an orientation equivalent to the 'survey' posture of Ano lis and other Iguanidae. Some aspects of the temporal dynamics of the behaviour were investigated. It was most commonly seen in adult males during August, when there were significant trends for the frequency of the posture to increase towards the base of the wall and for the mean time spent immobile in the posture to be greater than the mean times immobile at other orientations. The 'survey' posture at the middle and higher levels of the wall appeared to be associated with topographica l features such as small tufts of vegetation or bricks which stood pro ud from the remainder. This association could not be tested directly, but fixing a small strip of wood to the wall increased the duration of locomotor pauses and the frequency of 'survey' postures of lizards wh en they were immediately above it.