THE TF&G REPORT

TEXAS HOT SHOTS
August 25, 2016
DEER SCHOOL by Chester Moore
August 25, 2016

Texas-Born Blue-wings? Yes, and ’Gators Eat Mottled Ducks, Too!

The vast majority of ducks (besides mottled, wood and tree ducks) are born and live their spring-summer months in the prairie pothole region of Canada and the United States.

Blue-winged teal, the first birds to migrate south are among them, but not all blue-wings are migratory. Texas actually has a small breeding population.

According to Texas Agrilife’s Texas Breeding Birds Index flightless bluewing broods have been found in Texas as early as 19 April; depending on the age of the brood, this indicates nest initiation during the second week of March or earlier. This is quite a bit earlier than in their northern range.

Nests have been found in the Panhandle in playa lakes and along the Upper and Middle Coasts of Texas.

Hunters who report seeing teal in May and June while fishing the marshes of the state are not seeing early migrants. They are seeing birds that have settled into Texas.

According to Texas Agrilife, no surveys of breeding blue-wings are conducted in Texas; however, they are noted in various other studies.

Wood ducks also nest in Texas. Although little research has been conducted on them here, I uncovered an interesting study from the past initiated by the biologists Miller, Whitling, Montague and Foundation.

Male blue-winged teal

“Although winter foods of mallards and wood ducks (have been documented in several studies, no such research has been conducted in natural bottomland hardwood forests in eastern Texas. We collected 40 mallards and 38 wood ducks and sampled available foods in eastern Texas during winters 1987-1988 and 1988-89 to study food habits and preferences. Acorns from four oak species comprised 89 percent and 99 percent of the diets of mallards and wood ducks, respectively.”

“Nuttall oak acorns made up 67 percent of the diet of each species both years. Seeds of holly and willow oak acorns were favored by mallards and wood ducks, respectively; preferences overlapped widely among potential foods, however. Although bottomland systems provide critical habitat for wintering waterfowl…”

An article in Southeastern Naturalist reported on a study by Ruth M. Elsey, Phillip L. Trosclair III and Jeb T. Linscombe on alligator predation of mottled ducks.

“Although the alligator has been noted to prey upon mottled ducks, evidence of mottled duck consumption is rare in numerous studies of alligator food habits. This may be due to the season and habitat from which alligators were collected for evaluation (often autumn samples from deep water habitats preferred by adult alligators). We examined stomach contents of alligators in summer (when mottled duck broods and molting adults are flightless) from shallow water habitats preferred by mottled ducks.

“Mottled duck remains were found in 20.9 percent of 43 alligator stomachs examined, far more than the highest frequency occurrence previously reported (1.27 percent). Unexpectedly, three relatively small alligators (1.51–1.70 m total length) consumed mottled ducks, and the sixteen largest alligators did not. This study underscores the importance of season and location of collections when evaluating stomach content data.”

Speaking of mottled ducks, according to the U.S. Fish and Wildlife Service (USFWS) they outfitted mottled ducks with small transmitters that allow biologists to track the movements of individual birds for up to five years. In 2011 biologists tracked more than 120 individual birds.

“The results indicate that mottled ducks, which normally avoid open water, have begun spending extended time offshore in the Gulf of Mexico. Scientists suspect habitat loss and saltwater intrusion, both a result of coastal development, may be forcing the ducks out of their wetland habitats. Coastal research in other regions shows similar trends, indicating the problem may be more than just local. Studies such as this help biologists and land managers better understand the issues and how to address them for the benefit of the mottled duck and other species that are also dependent on wetlands.”

“The mottled duck is considered an indicator species for coastal marsh and wetland health by the U.S. Fish and Wildlife Service. This species of waterfowl is increasingly less common along the Texas Gulf Coast, with population levels currently gauged to be 17 percent below the goal numbers established by the Gulf Coast Joint Venture for Texas as necessary for a stable population.”

—from TPWD

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