LOOKING AFTER OUR NATURAL HERITAGE
What is fairly certain in southeast Texas is seeing big, white birds known as Great egrets cruising overhead, dozens of Cattle egrets chasing behind a mowing tractor and, with good reason, a Roseate spoonbill being mistaken for a flamingo.
Since 2002, on the Memorial Day weekend, the SLSP's rookery count is held as part of the Texas Coastal Colonial Waterbird Census coordinated by USFWS.
Barely four generations back, in the early 1900's, several species of these elegant waterbirds were hunted to near extinction for their beautiful breeding plumes used to decorate the hats of fashionable ladies. With support from the public, state and federal laws were enacted to protect these birds.
It took much of the last century for the colonial waterbird, many species populations were reduced to hundreds, to recover.
Today, Houstonians coexist with thousands of waterbirds in the urban sprawl of America's fourth largest city. To keep them a vibrant part of our natural landscapes requires watching out for them by looking at them a bit closely during nesting season. That's why FOSL volunteers conduct the SLSP's Annual Rookery Census.
Waterbirds are colonial because they nest in large colonies in close proximity, often just feet away, to other similar bird species. In fact, one waterbird species will inherit the nest of another when the first's brood has fledged. Herons, ibis, spoonbills and egrets are also known as wading birds or waders because they often wade while hunting.
Waterbirds forage primarily on aquatic prey in fresh and brackish water. Most waterbirds eat frogs, fish, shrimp, snakes and crawfish but they will take large insects like grasshoppers and dragonflies.
Each year the crew of FOSL volunteers drive on the levee in an TPWD pick-up outfitted with a totally cool observation platform.
Peering through spotting scopes, volunteers search the lake's 30+ spoil islands' jumble of Chinese tallow, Black willow, hackberry and Bald cypress tree limbs for nests. The busy waterbird traffic to and from the rookery is tallied too.
Chances of Purple gallinule sighting are common. Black belly whistling duck also nest on the islands. Alligators are watched too as they move around the rookery islands for the unfortunate nestling or fledgling the accidentally falls from the safety of the nest. Butterflies and songbirds are breeding as well and provide a nice diversions for the crew.
Two days of surveying isn't all fun. By Memorial Day at SLSP the weather is summery. There's no shade on the levees. The lightest breeze is welcomed with a sigh of relief then a groan when it quits. Mosquitoes and fire ants are constant companions.
FOSL counters put up with the sun and bugs because they know these gracious, kite-like fliers are a part of our natural heritage protected on SLSP. FOSL wants future generations to see herons frozen in a hunt stance in a drainage ditch and chasing mowers in a field. Counting the waterbird colony generates the data to help conserve this important part of the area's natural landscape.
Elegant waterbirds have made a comeback and we hope they'll stay around for future generations of Texans. You can help by joining FOSL!
Things you learn watching the rookery:
- Waterbird species have one brood of about three eggs per nesting season.
- Eggs are laid a few days apart and hatch out at different times.
Great egrets nest the earliest often seen in late February displaying their breeding plumage and building nests.
Green heron are very secretive nesters. Their nest are built in dense tree limbs or button bush just above water. Finding a Green heron's nest means waiting for an adult to return with food for its young.
Cattle egrets nest the latest starting around the last week of April. They assume many vacated nests of Little blue herons that have been fledged of young.
- Over nine years SLSP rookery counters have tallied 13,974 nests and 19,270 adult heron, egrets, spoonbill, Anhinga, cormorant, pelican and extras species we like to keep track of.
- Two-thirds of all nest and adults counted in eight years belong to Cattle egrets.
- Waterbirds prefer to nest in trees surrounded by open water. Sheldon Lake's 29+ spoil islands make perfect waterbird nesting habitat.
- Yellow-crowned night heron are a notable exception and will nest in mature trees (preferably Live oak) over green belts, street, sidewalks and backyards.
- White ibis are the second most prevalent species.
- The first White-faced ibis nest was found in 2006.
