Data from: Shorebirds are shrinking and shape-shifting: Declining body size and lengthening bills in the past half-century

Animals are predicted to shrink and shape-shift as the climate warms;
declining in size, while their appendages lengthen. Determining which
types of species are undergoing these morphological changes, and why, is
critical to understanding species responses to global change, including
potential adaptation to climate warming. We examine body size and bill
length changes in 25 shorebird species using extensive field data
(>200,000 observations) collected over 46 years (1975-2021) by
community scientists. We show widespread body size declines over time, and
after short-term exposure to warmer summers. Meanwhile, shorebird bills
are lengthening over time but shorten after hot summers. Shrinking and
shape-shifting patterns are consistent across ecologically diverse
shorebirds from tropical and temperate Australia, are pronounced in
smaller species, and vary according to migration behaviour. These
widespread morphological changes could be explained by multiple drivers,
including adaptive and maladaptive responses to nutritional stress, or by
thermal adaptation to climate warming.