By Gwendolyn Clark, Marsh Monitoring Field Coordinator, and Jenna McDermott, Atlantic Programs Biologist
If you can imagine being knee-deep in the reeds of your local marsh, you’ll know just how difficult it can be to get around in these soggy places! Marshes are wetlands where the water levels rise and fall periodically. As a result, they usually have some combination of shallow water and exposed mud. Birds that call these habitats home have the challenge of foraging, travelling, and hunting all while dealing with these mucky and watery conditions. Join us as we wade into the amazing adaptations they use to thrive in wet habitats.
Toe-tally at home: Crazy wetland digits
Many marsh birds spend a lot of time on the ground, weaving through dense stands of reedy vegetation.
Any earth-bound wader (like you or me) would feel the mud in these areas trying to suck them in. So how do marsh birds avoid getting stuck? With amazingly long toes!
Rails are the champions of the long-toed marsh birds! Members of this bird family, like Soras and Virginia Rails, have toes that are about as long as their lower leg bone.
For the largest species, the King Rail, they are up to 6 cm long. Proportionally, in humans, this would translate to toes over 20 cm long! The elongated toes spread the bird’s weight across a larger area, like built-in snowshoes. This adaptation is so effective that rails can walk on floating lily pads – almost like walking on water!
Sora. Photo: aecole2010, CC BY 2.0. Note: Photo has been cropped.
Lobed, not webbed: Nature’s wackiest flippers
Some marsh birds trade the mucky mud for a wetter life, but moving in water has its own challenges. In order to swim skillfully, waterbirds need a foot design with some power. The most familiar is the webbed foot, as seen in ducks and geese. With thick membranes stretching between the toes, webbed feet are essentially paddles – perfect for surface swimmers and divers, like loons.
The problem is that webbed feet are not the most maneuverable; they’re simply too rigid. To solve this issue, a handful of birds have evolved what might be the most bizarre foot in the marsh – the lobed foot!
Pied-billed Grebe. Photo: cjmatheson. Note: Photo has been cropped.
In lobed feet (or “lobate” feet), the toes are separated, and each has a fleshy membrane on either side, resulting in a leaf-like appearance. Among diving birds, lobed feet are seen mostly in the Grebe family. Their fleshy lobes flatten out as the grebe kicks back, mimicking traditional webbed feet and giving a powerful push. With this feature, grebes navigate tangled underwater marsh habitats with power and precision. This is quite handy when chasing fish through submerged marsh vegetation. Talk about having your fish and eating it too!
Surprisingly, lobed feet also appear on another marsh resident, the American Coot. These birds spend a lot of time floating on the surface of ponds and lakes, so you might imagine that webbed feet would suit them best.
The problem? They also do a lot of walking on dry land and soft mud, where webbed feet are awkward. With lobed feet, the membranes fold back when the coot walks, so they can use their toes for agility. The lobes can also spread out to further prevent sinking into soft surfaces. That’s some multi-purpose footwear!
American Coot by Frank King. Cornell Lab of Ornithology | Macaulay Library
Hold on tight: sticky soles and rotating toes
Marsh birds showcase an amazing variety of fishing techniques. Some plunge headfirst while others stalk from the reeds. One of the most spectacular is the feet-first “splash-and-grab” favoured by raptors. As Canada’s only specialized fish-eating raptor, the Osprey is the undisputed “splash-and-grab” champion, and has the feet to prove it.
Ospreys have reversible outer toes. They perch with three toes forward and one backward, like most raptors. When holding a fish, however, they swivel the outer toe back for a “two forward, two back” approach, giving them a more secure grip on their long, slippery prey. The sharp spines on the bottoms of their feet further improve their grip. Finally, their heavily curved talons act like hooks to grab their prey. With mobile fish traps for feet, it’s no wonder that Osprey hunting success can reach 75% in some populations!
Osprey. Photo: Caroline Legg. CC BY 2.0. Note: the photo has been cropped.
How to get your feet wet
We hope by now you’ve gained an appreciation for the awesome adaptations of marsh birds. If you’re eager to learn more, consider checking out your regional MarshWatch program. This beginner program will get you identifying wetland birds and amphibians like a pro in no time! If you’re looking to dip your toe into volunteering, you can also join the Marsh Monitoring Program to survey these amazing birds.
Can’t get enough? Our Marsh Monitoring Field Coordinator, Gwendolyn Clark, recently joined The Warblers podcast to talk more about marshy adaptations! Take a listen here or wherever you get your podcasts.
