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unraveling the texas knot

by Larry Niles
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Fish killed from a red tide event on Padres Island TX. photo by Barbara KeelerAs David Newstead and I started our week of fieldwork on Padre Island National Seashore, we were hoping for better conditions than the catastrophic fish kill that blanketed Texas beaches last fall. There to trap shorebirds, we mostly spent our time riding the 60 mile long undeveloped beach near Corpus Christi, TX, documenting one of the worse red tide events every to occur on the Gulf Coast. The deadly toxin from the algae bloom, killed fish and birds particularly red knots. At the beginning of our trip, last year we saw a few hundred red knots, by the end of our trip we found only dead or zombielike birds debilitated by the lack of food and toxins. We thought the plague had decimated the population.

It did notIn fact, our estimate of the population grew over this winter.   The story of that increase is one that would warm the heart of any biologist that holds on to the ideal that proper studies are the foundation of all good conservation.

When David Newstead, Humphrey Sitters and I started our project, we knew little of the red knots in Texas. In our 2008 assessment of status Studies of Avian Biology Monograph no 36), we estimated only a few hundred knots using the Gulf Coast of Texas. At the time, we thought most were passing through Texas either to or from unknown wintering areas in South America. We knew nothing of their migratory flight path to their breeding areas in the Arctic.

A map of the flights of five red knots with geolocators attached and recovered in Padre Island , TXOver the last three years, we found our assumptions were wrong. First we learned from recovered geolocator data (tiny devices that record location) that birds did not leave Texas in the winter, but rather moved to the bay behind the Gulf beaches called the Laguna Madre. The Laguna spans hundreds of miles from Texas to Mexico. Its shallow waters of less than a few feet deep, fluctuate not so much by tide but wind. In other words, Texas knots spend 9 months of their lives in Texas.

This year we found out even more about the birds from tiny transmitters David Newstead attached to the few knots we did catch last fall. During the winter, he closely followed their movements and found a mother lode of knots. We thought 700 knots used TX before he started his search. After David’s discovery, the actual number may be more than 2000.

There’s more. After our discovery of knots in the Laguna, we thought they left the beach in the fall,spent thier winter in the Laguna and returned in spring to the gulf beach. As it turns out, the relationship between the two habitats is more complicated. David found that knot use varied with fluctuations in the water levels of Laguna Madre: At low levels, knots use the Laguna, at high water levels they use the beach. Our work this spring substantiated this pattern, when we started, levels were high in the Laguna but dropped steadily over the week. Correspondingly bird numbers on the beach were high when we started and lowered throughout the week.

David Newstead with TX knot in his hand. The progress of this study is testament to our work especially Davids and his team of professional and amateur volunteers, and the need for skilled field work. Like many studies done around the globe, this study sheds light on the intricate relationship of an animal and its environment. These studies are the backbone of any significant conservat
ion effort that seeks to thread the needle through the needs of both animal and manWithout good wildife studies,  we are only guessing and ultimately wasting the already limited money that now goes into American wildlife conservation.

The work also points to the best way to get this valuable data in a cost effective way. In a world of diminishing resources devoted to conservation, volunteer professionals and amateurs amplify the work of paid staff. With the good use of volunteers, biologists, like David can accomplish so much more. This includes people like Frank Weaver a wildlife biologist for the USFWS working on other projects, and Phil Magasich, a volunteer hoping to help wildlife in a meaningful way. The Texas team like similar teams in South Carolina, Massachusetts and of coarse the Delaware Bay is the new way to make field work a reality in a time when too few people see it as crucial.The Texas banding crew.

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