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The Run Has Begun

Fri, Jul 20th, 2001
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Weaver Dunes Field Report Early Summer 2001By John LevellMonday, July 23, 2001

As Spring 2001 draws to a close, the season's exceedingly wet and cool weather is still cause for concern to those of us working on the Blanding's Turtle project at Weaver. Is the unbelievably small number of animals captured thus far really just a reflection of difficult working conditions, or has low temperatures and an overall lack of sunshine resulted in an actual change in normal turtle behavior?

These animals are after all cold-blooded, dependent on environmental heat for the warmth required to complete all necessary bodily functions. Digestion, mating, the production of eggs, even movement, only possible within a relatively narrow thermal range and all inextricably intertwined to the vagaries of weather.

So how will local turtles respond to what, from our standpoint at least, were seemingly far from ideal ecological conditions? Has the well below average temperatures of spring disrupted the timing of seasonal turtle activities? If so, will these seasonal activities be simply delayed or will some, nesting perhaps, be abandoned altogether?

By the final week of May, the start of the Blanding's Turtle nesting season last year, it is abundantly clear that the timetable of "turtle events" at Weaver is already behind schedule. X-rays of some females, hand-caught in Kelly's Pond, reveal that most have yet to develop shelled eggs.

Not surprisingly, this only increases our trepidation. No Blanding's Turtle nesting migration would mean that weeks of physical effort expended installing a half-mile of drift fence will amount to nothing more than wasted time. With this far from pleasant thought firmly in mind, all we can do is wait.

On the sixth day of June, the peak date of nesting activity in 2000 with over 180 Blanding's Turtles processed, the first dozen or so females of 2001 finally turn-up on our fence. Physical examination and more x-ray photography confirm that these "old girls" are indeed loaded with eggs, an unexpected surprise considering the previous week's view of the reproductive condition of our females.

Cautious optimism concerning the start of the 2001 nesting season is tempered somewhat by the small number of turtles captured over the next few days. On June 10, for example, only twenty-five or so Blanding's Turtles are found, despite a full evening of checking fences and patrolling area roads. This is particularly disappointing for the large group of "turtle catchers" led by naturalist Dave Palmquist of Whitewater State Park, who have chosen this date for their annual day of volunteer assistance to the Blanding's Turtle project.

As luck would have it things would change dramatically starting on June 11, a day coincidently also memorable due to the lack of any project volunteers. On this date, 90 female Blanding's Turtles laden with eggs embark in mass on the preliminary outbound leg of their seasonal nesting forays.

Nesting activities explode on June 12, when nearly 250 female Blanding's Turtles are trapped at our drift fence or picked-up while crossing area roads. Although we do not realize it at the time, June 12 also marks the first of four consecutive days in which we will capture in excess of 100 animals.

At this vitally important stage of their annual cycle, each reproductive female must be processed and released as quickly as possible. For animals marked in previous years, processing is a relatively straightforward procedure of individual identification coupled with the collection of basic supplemental data on length, weight, and reproductive condition. Turtles not captured during earlier years of study must be more thoroughly documented, however, with preliminary data on the length and width of the upper and lower shell, the turtle's overall height, weight, and so forth collected and noted along with any visible scars or unusual physical characteristics. New turtles must likewise be permanently marked with a readily distinguishable code prior to being released.

Processed animals are also given a quick spot of paint, which helps to avoid unnecessary collection of duplicate data sets. While lending a somewhat avant-garde quality to the turtles so treated, painting does prove particularly helpful after the first few days of the nesting season when a confusing mixture of both inbound and outbound animals crisscross enroute to and from their nesting grounds.

By the twenty-second of June the nesting run is over, completed as abruptly and decisively as it began. While the majority of this year's data has yet to be analyzed one thing at least can be stated with certainty; our initial concerns regarding the 2001 Blanding's Turtle nesting season most definitely proved unfounded. Over the 17 days of actual nesting activity, our drift fence captured a total of well over 1100 individual females including approximately 25 percent that had never been previously encountered. This figure is indeed representative of individual Blanding's Turtles and does not include multiple records for any animal captured more than once. Actual number of turtles handled on the fence is therefore significantly higher.

With Blanding's Turtle nesting activity peaking between 4:00 and 8:00 PM, processing 100 animals or more for morning release makes for some very long nights of work indeed. Discovering additional aspects of the biology and behavior of this placid turtle, tidbits of knowledge that may prove invaluable in conserving this state threatened species, does make the effort worthwhile. Until next time "Nuff Said" – JPL

John Levell

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