John K. Flores: Mottled duck study designed to reverse decline

In mid-August southwest Louisiana’s heat is sweltering. Daytime highs are in the mid 90s and the “feel like” temperatures are 100-plus degrees. What’s more, there’s no relief until sunset, where a group of biologists from Louisiana and Tennessee gather outside of a boatshed on Rockefeller Wildlife Refuge preparing for a night mission to catch mottled ducks.
The mission is an important one. Approximately 90% of the worlds mottled duck populations live on the western gulf coast. Moreover, these southern birds have been in long-term decline for two decades.
Paul Link, Louisiana Department of Wildlife and Fisheries Research Program Manager at RWR, said, “This at a minimum is a three-year project where the objective during this initial pilot year is to deploy 30 GPS GSM implant transmitters on females to determine breeding propensity, where we learn how many initiate a nest, what the co-variants are and what drives that — what triggers a duck to say no or yes when it comes to nesting — and what are the habitat conditions.”
“We’re hoping at the end of three-years,” Link continued, “to have enough variation annually, among sites, to compare delta marsh in the eastern half of the state versus chenier marsh on this side of the state.”
Department officials note that the transmitters will help biologists to track habitat use, mottled duck movements and nest site selection, along with their success and survival, with unprecedented accuracy.
The best time of the month to night hunt is during a waning crescent moon, when near total darkness is covering the landscape. August is also the month when mottled ducks are molting and flightless. Under this cloak of darkness, biologists can take full advantage of the near perfect conditions, where an airboat driver can tactically maneuver his watercraft through the marsh while using a handheld spotlight to locate mottled ducks at a time when they are most vulnerable.
When detected, the ducks do their best to swim away or hide in the marsh cord and salt grasses, but they’re no match for the airboat and catcher who safely captures and places them into crates.
Variables are important when it comes to breeding strategies. Link pointed out mottled ducks share some similarity to pintails where if conditions aren’t perfect, they’re known to forgo nesting, unlike other puddle ducks.
Link said, “There’s some studies that have shown that. Like during drought years, there’s a lot of mottled ducks that act just like pintails on the prairie. If it’s not perfect, they make that decision to not nest. The theory is that they just say, ‘I’m just going to survive and hope conditions are better next year.’ So, that’s kind of why their population doesn’t respond as fast as prairie ducks like blue winged teal, for example. Blue winged teal are like, ‘I only have a 50 percent chance of surviving. I must breed. There is no choice. I have to move my progeny onward.”
For the 2025-26 waterfowl season, no mottled ducks may be taken for the first 15 days of the season with one per day allowed for the remainder of the season.
“We’re on the verge of losing mottled duck harvest. We’re at that stage where we have to come up with something bold and big to try and reverse a two decade decline in mottled duck numbers,” Link said.
The biggest issue Link points out is the quantity and quality of healthy, stable habitat across the landscape where mottled ducks are concerned, and not hunting harvest. Agricultural practices, fire ants, predators, the use of herbicides, burning, drought, and torrential rains all compound the problem making it extremely challenging.
Link said, “It’s this death by a 1,000 nicks thing. We have decreasing quantity and quality of habitat, and the breeding propensity is just not there unless everything is perfect. With all the weather changes we’ve had, there’s nothing normal anymore. It’s just valleys and peaks. We ride these ridges from stupid wet to epic dry.”
By looking at successful nests to determine what their elevation and water level is, and pinpointing what types of vegetation is around them, Link says conservation efforts can be focused on how to try and replicate them. He envisions creating a demonstration site with temple mounds, surrounded with dense nesting cover in shallow brood water, as one possibility.
Department officials announced early results are expected as soon as the 2026 nesting season with full analysis by 2028.
Initial funding for the project was provided by the Louisiana Legislature and partners that include the Louisiana Waterfowl Working Group, Ducks Unlimited, Conoco Phillips, and Tennessee Tech University.
John Flores is the Morgan City Review’s outdoor writer. He can be contacted at gowiththeflo@cox.net.