by Bryan Dixon
Types of wetlands in the Cutler Marsh
Benefits of wetlands to humans
More information on wetlands & wetlands organizations
More information on wetlands flora & fauna
Types of wetlands in Cutler Marsh
Riverine Systems (streams) carry more
oxygen than still waters and their gravelly stream bottoms provide hiding
places for small invertebrates. The smaller invertebrates become food for
larger invertebrates such as caddisfly larvae. Fish look for these spots
as a replenishing food source. Birds, such as Belted Kingfishers and Forster's
Terns, dive into the water to take fish. Other birds, such as Great Blue
Herons and egrets, wade in the shallows for their fish. Snowy Egrets have
even evolved with yellow toes, which they dangle ahead of them as bait,
waiting for fish to take the nibble - only for the fish to become a nibble themselves!
Riparian Zones (along stream banks) provide
a unique boundary habitat (ecotone) where animals can take advantage of both wet
and dry habitats. Banks just above water level are used for nest sites
by geese and ducks. Once hatched, the young have only a short distance
to go to reach the safety of water. Look for writhing masses of garter
snakes on south-facing banks in the spring; they're taking advantage of
the warm sun on cool days. Muskrat and beaver will leave the water to feed
on the shoots and bark of shrubs and trees, but they build their huts among
the reeds and rushes and even hollow out tunnels in the banks, where they
can be safe from roaming canines. Deer, elk, and even moose have been observed
in the Wetlands Maze Area feeding on the willow shoots or hiding in the dense
cover of summer growth. The structural diversity of the riparian shrubs
and trees provides a mix of food and cover, and wherever there's a diverse
plant community, we find a diverse animal community.
Shrubs and trees also provide safe nesting places for Yellow Warblers,
Warbling Vireos, Willow Flycatchers, Eastern Kingbirds, Common Yellowthroats,
and Bullock's Orioles. Great Blue Herons build colonies of nests in trees.
In early spring you may even see Great Horned Owls - or perhaps a Canada
Goose - usurping these high platforms for their own nests. Once evening
insects are plentiful a variety of bats roost in the trees, though they're
harder to find because they’re nocturnal.
Upland Fields and Wet Meadows beyond the
riparian zone along the edge of the Maze may look dry for much of the year,
but part of the year these lands often have standing water. Plant species in
these wetlands must be specially adapted for seasonal fluctuations. Spring
rains and warmer temperatures result in new green shoots growing up through
last year's brown stubble, and animals take advantage of the bounty. Chorus
frogs blend their raucous voices on spring evenings. Sandhill Cranes arrive
to feed on young plant shoots and insects. Meadow voles, mice and pocket
gophers lace the ground with burrow entrances and runways, but they'd better
watch out, because coyotes, fox and other mammals may be waiting patiently
at the ends of these "rodent roads." In the air, Northern Harriers and
Short-eared Owls fly low, listening for scratching sounds, and their broad
wings and long tails give them superb maneuverability to turn and dive
suddenly for a bit of fast food.
One of the first signs of spring is the Killdeer's familiar "ka-DE ka-DE".
These small shorebirds with a black double neck-band scratch out a nest in the
stones but the eggs are almost impossible to find. On summer's evenings,
look for White-faced Ibis flying low - dark, slender shorebirds with downward
curving bills flying in tight formation, heading home to their rookery
north of the Valley View Highway.
Another important habitat in these upland wetlands is the buffer zone
along the edges of fields where farmers leave higher grasses. These tall
grasses look "weedy and unkempt" but provide cover for Ring-necked Pheasants
and Savannah Sparrows.
Playa Wetlands (alkali mud flats) look desolate
along the edges of the Wetlands Maze; it seems they're just sticky mud
after spring rains, or crunchy crisp in mid-summer. But although sparsely
vegetated, there are plants here such as salt tolerant pickle weed and
knot weed, though few animals can eat them. The real bounty lies beneath
the surface in the form of invertebrates and crustaceans. Different species
of these tiny animals live at different depths below the surface, and shorebirds
have evolved with different bill shapes to take advantage of this diversity.
Watch American Avocets sweeping the surface of shallow waters for swimming
insects but notice how the Black-necked Stilts (the ones wearing a "tuxedo"
plumage) probe the mud. Long-billed Dowitchers can be recognized from a
distance by their sewing-machine-like feeding. Look for Willets, perhaps
the most common shorebird, with their relatively thick bills and black-and-white striped wing patterns that are displayed whenever they land.
In early spring, and again in late summer, look for appropriately named
Greater Yellow-legs, with large and slightly up-curved bills, and the Lesser
Yellowlegs with proportionately smaller bills. All of these shorebirds
depend on shallowly submerged or exposed mudflats for their dinner.
Emergent Wetlands are the most prominent
form of wetlands in Cutler Marsh. Here the water is shallow enough that
plants can anchor their roots in the bottom silts and yet reach upward
above the surface for air and sunlight. The two most common plants are
cattails and hardstem bulrush. Where the water is shallow, a variety of
birds use these plant communities for cover, nesting and food. These birds
are very difficult to see, but you can hear their voice as dusk settles
in early summer. Listen for the haunting "pump-pump-a-LUNK" of the American
Bittern. The Sora makes a sound like its name, "so-RAH so-RAH". The Virginia
Rail utters a repeated "ka-DICK ka-DICK".
In the upper reaches of the cattails you may find other birds. Marsh
Wrens are the tiny chattering birds that always seem to keep their tails
pointed upward. Look at them through binoculars to notice the beautiful
brown and black colors on their backs. Common Yellowthroats are another
bird that you may find easier by voice. This small warbler has a distinctive
song, "WITCHity-WITCHity-WITCHity", but also a beautiful yellow breast
with a striking black mask.
Open Water is another important habitat in
the Wetlands Maze. Technically, "open water" means water too deep for emergent
plants to root. Safe from land-based predators, here we find the swimming
birds of the marsh. Some of these birds rely on the plants for food, some
dive for fish. In spring, you'll see waves of different species beginning
with ducks such as Northern Pintails, Redheads, and Green-winged Teal.
Early in March, look for the regular flock of 50-70 Tundra Swans. By late
March and early April, you'll see American Pelicans with their bizarre
"nose knobs" that disappear in summer. Also by summer we find Double-crested
Cormorants, Western and Clark's Grebes. And ever-present are the American
Coots, which, although similar to ducks, actually belong to the family
of Gallinules. These birds are specially adapted for diving, with flaps
on their toes that only stick out when being pushed back in strong swimming
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