Ross T. Huffman
M.S., Texas Tech University, 2005
Nesting activity of Rio Grande wild turkeys (Meleagris gallopavo intermedia) was monitored from 2000 through 2004 at 3 sites in the Texas Panhandle and 1 site in southwestern Kansas. During this time 360 adult female and 282 juvenile female wild turkeys attempted 396 nests. A total of 129 (33%) nests successfully hatched. Nesting rate did not vary among sites (P = 0.2289), but it did vary among years (P = 0.0069). Nesting success did not vary among sites (P = 0.2871) or years (P = 0.2453), but did range from a low of 15% to a high of 58%.
No relationship was found between pre-nesting precipitation (September-March) and nesting rate of first nest attempts (P = 0.207), or nesting success (P = 0.8495). Nesting season precipitation (April-July) had no relationship to nesting success (P = 0.1542), nor did the number of days with precipitation during nesting had no relationship to nesting success (P = 0.106). Days since precipitation for depredated nests (moisture-facilitated nest depredation hypothesis) did not conform to any distribution pattern. However, almost 30% of nests were depredated on days with measurable precipitation.
Using data from 269 nests stepwise logistic regression selected 3 variables into a model predicting nesting success. Pre-nesting precipitation (PRE) and number of rainfall events during nesting (EVENTS) had a positive relationship to the success of a nest while the week of nest initiation (WEEK) had a negative relationship. More precipitation during pre-nesting, more rainfall events during nesting, and initiation of a nest early in the nesting season increased the probability of a nest being successful.
Height of visual obstruction did not differ between successful nests and unsuccessful nests. Mean height of visual obstruction at successful nests and unsuccessful nests was 0.5 m. Regardless of nesting outcome nest sites had greater height of visual obstruction than paired random plots. This relationship held among all years and all sites except at the Matador WMA in 2001. In 2003 and 2004 females selected for greater height (0.4-0.5 m) of visual obstruction and avoided lower height (0.1-0.2 m) of visual obstruction (P < 0.001). In 2004 nests sites with trees in the nesting area were selected for while nest sites without trees were avoided across all study sites (P < 0.001).
Managers can use local weather data to determine the probability of nests being successful, this may allow for estimates of recruitment into the fall populations. Managers should develop habitat management plans that maximize visual obstruction available for potential nesting habitat.
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Butler
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11/06/06