A banded Swainson’s thrush is one of biologist Samantha Collins' target species for the research she is conducting. (Submitted Photo/Courtesy of John K. Flores)

NanoTag studies help biologists learn more about coastal cheniers

A drive down Grand Chenier Highway during rush hour is nothing like traveling in New Orleans at first light. In this remote region of southwest Louisiana, the closest thing to being in a hurry is the bird banders and mist net assistants making rounds under the beautiful old growth, tree-lined cheniers, during the annual bird migration.
Samantha Collins is a biologist who has worked for the Louisiana Department of Wildlife and Fisheries on Rockefeller Wildlife Refuge since 2014. Collins, 32, earned her Master of Science Degree in Wildlife and Fisheries from Clemson University in 2012.
Prior to being offered a graduate research assistantship at Clemson, whereby eventually earning her Masters, she says she bumped around several states as a technician trying to learn all she could.
Following her Master’s program, the young biologist ultimately wound up at the U. S. Geological Survey’s Bird Banding Laboratory at the Patuxent Wildlife Research Center in Maryland, where she recorded band data.
According to Collins, it was all good experience preparing her for the research work she is doing for the Louisiana Department of Wildlife and Fisheries on Rockefeller.
For approximately 20 years, the University of Southern Mississippi, under the direction of Frank Moore, operated a migration station in Johnson Bayou. Located some 60 miles west of Rockefeller Refuge, along the gulf coast near the Texas border, the station is just one of several that acts as study and research locations where biologists and technicians record every bird they hear, see or catch in mist nets. The data obtained is critical information for the development of habitat management strategies and determining the health of avian populations.
In more recent years, cattle grazing began to alter the landscape on the Johnson Bayou site, causing it to somewhat decline as a research location.
About that time, Collins had come on board with the Louisiana of Department of Wildlife and Fisheries.
Stepping in, she contacted Moore to offer the Nunez Woods property across the road from the refuge to continue the important migration research.
The Nunez Woods property happened to be an old growth chenier with rich stands of pristine live oak and hackberry trees that is leased by the department for research purposes. In short, the offered site is perfect for migrating songbirds.
And, in 2015, Collins was able to work with Moore where funding was obtained to operate a migration station that year.
As it turned out, 2015 proved to be very successful, and the Nunez property produced lots of birds, Collins says.
“It was a very productive site. We caught a lot of birds, and there was even some species like Swainson’s warblers that we caught more of on Nunez than they had ever caught at Johnson Bayou,” Collins said.
In 2016 and 2017, there were no funds available to operate the migration station on Nunez Woods.
But, in 2018, a couple of critical research projects came up. One measuring the tick load of migrating birds, where studies show birds often carry these parasites.
And the other, comparing weather radar migration data with actual information from migration stations on the ground.
In addition to the Nunez Woods site, further down the road, the Nature Conservancy manages a conservation easement they negotiated with landowners to support wildlife, particularly migrating birds. Known as the Hollister Chenier Preserve, the property is roughly 50 acres in size and by comparison is newer succession growth, consisting mainly of lower canopy woods and shrub understory.
Having both Chenier habitats close by is ideal for Collins and the research she is involved in with the department. Coastal erosion, hurricanes and land use all have reduced the available chenier acreage along the coast to a fraction of what it once was on the coastal prairie.
“These cheniers are basically endangered in this area,” Collins said. “They were historic ridges on the landscape from where the Mississippi River used to flood and when we had open channelization where the Gulf of Mexico met the land. In flood years, it would create these little ridges, and that’s what these cheniers are – little ridges – though not very high.
“One of the studies I’m doing is looking at the value of these cheniers to songbirds,” Collins added. “We’re looking at things like the vegetation composition and availability of prey at both sites. So, we’re doing fruit sampling and arthropod sampling, looking for – you know – what kinds of bugs are here and what kinds of fruit.”
Collins also is involved in the Motus Wildlife Tracking System program currently managed through the Louisiana Natural Heritage Program arm of the Louisiana Department of Wildlife and Fisheries. Motus is Latin for movement and is an international collaborative research network that uses a coordinated automated radio telemetry array to track the movement and behavior of small flying organisms (birds, bats and insects) by definition.
Essentially, tiny avian NanoTag transmitters emit signals to antenna arrays located along the coastline that track migrating birds as they fly overhead. Signals from NanoTags can be detected 10 to 15 kilometers (6 to 9 miles) away. The only drawback is the antenna towers cannot detect birds down on the ground or obscured by vegetation.
One of the things Moore has looked at is the availability of suitable habitat during migration where energy stores critical to a successful migration can be safely deposited.
In Collins’s NanoTag research, she has chosen Swainson’s thrushes and northern water thrushes. Her reasoning is both of these species are northern latitude birds capable of traveling long distances during the spring migration.
And, by the numbers of them caught at the Nunez Woods migration station in 2015, they would be good candidates to study the importance of chenier habitats as key stopover locations for them to rejuvenate during migration.
“We’re looking at their age class and their condition,” Collins said. “We’re looking at their fat and muscle scores. We want to know if a low fat, low muscle bird takes longer to migrate north, or would they stay here longer to refuel. Or, would fatter, healthier birds get up there quicker. Those kinds of questions we really haven’t been able to ask before.
“Essentially, songbirds rely on these Chenier habitats to refuel,” Collins added. “And, if they can’t make it to their northern habitats to breed, then populations are going to suffer because of that.”
Spring birding is allowed on Rockefeller Wildlife Refuge. Visitors must check in at the Refuge Headquarters that is open from Monday through Friday from 7 a.m. to 5:30 p.m.
For more information on the Motus Wildlife Tracking System, visit www.motus.org.
EDITOR’s NOTE: John K. Flores is The Daily Review’s Outdoor Writer. If you wish to make a comment or have an anecdote, recipe or story you wish to share, you can contact Flores at 985-395-5586 or at gowiththeflo@cox.net

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