Examples of cryptic Patagonian birds showing their morphological similarities. A–C: goose species Chloephaga poliocephala (A), Chloephaga rubidiceps (B) and Chloephaga picta (male on the left and female on the right) (C); D–F: oystercatcher species Haematopus palliatus (D), Haematopus leucopodus (E) and Haematopus ater (F), showing a uniform morphology with red, long and strong peaks; G–I: steamer duck species (female on the left and male on the right) Tachyeres patachonicus (G), Tachyeres pteneres (H) and Tachyeres brachypterus (I), with minimal differences in color pattern at beak and head regions; T. pteneres has shorter wings than T. patachonicus due to its flightless condition.