Figure 1.

Proportions of wintering male (white) and female (gray) Icelandic black-tailed godwits in the seven main winter regions. Chart size is proportional to the number of marked individuals recorded in each site with numbers reported within each chart. Note that expected sex ratios are not equal (i.e., 1:1) and vary with the capture season and location of these individuals – see Methods for details. The inset shows the 18 sites at which godwit foraging behavior was recorded, and the six sites (3, 6, 8, 9, 13, and 18) at which prey were sampled, on the intertidal mudflats (light gray) of the Tagus estuary, West Portugal (dark gray indicates the area below mean low water).