How do the feet of finfoots and coots help them swim?

Finfoots and coots possess specialized feet that facilitate their movement in aquatic environments. Rather than having fully webbed feet like many other swimming birds, both groups feature lobes on their toes.12

• Finfoots: These semiaquatic birds are named for the lobes on their feet, which provide the necessary surface area to swim effectively. These adaptations also allow them to clamber across fallen trunks and branches in their forest habitats.3
• Coots: These ducklike birds have toes fringed by a lobed membrane. This structure serves a dual purpose: it facilitates swimming in inland waters and streams, and it aids the birds in walking over plant-choked marshes and soft ooze.4

While many swimming birds rely on webbed feet for propulsion, the lobed toes of these Gruiformes represent a distinct evolutionary adaptation for navigating both water and vegetation.13