Fig. 2From: Spatial variation in avian bill size is associated with humidity in summer among Australian passerinesThe association between bill surface area (log-transformed) and humidity for 36 species passerine from the Meliphagoidea (n = 2867 individuals). Humidity is mean summer water vapour pressure (hPa) averaged for the preceding 5 summers prior to capture; summer is defined as the months December to FebruaryBack to article page