Figure 4. Microhabitat use by male and female godwits in the Tagus estuary when feeding upon Scrobicularia plana, Hediste diversicolor and Hydrobia ulvae.

Microhabitat was classified into three categories according to the water level of foraging areas: (1) no water – birds feeding on exposed mudflats or oyster beds, (2) water below knee and (3) water above knee. Black dots in the ternary diagrams represent the proportions of microhabitat use calculated for each individual (in each study-season). Dot size (area) is proportional to the number of individual observations with the same coordinates. Average values of microhabitat use for each prey type and sex-class are represented by red dots; red-lines guide the readings in ternary graphics. Arrows outside the diagram indicate the increasing use of each specific microhabitat class.