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Gretchen E. Anderson

Publications and source records attributed to Gretchen E. Anderson.

3 recordsLinked to original sources

Arboreal habitat use by invasive Burmese Pythons in southern Florida

Understanding habitat use and behavior is critical to developing effective management strategies for a species. Burmese Pythons ( Python bivittatus ) are large-bodied snakes native to southeastern Asia that have become prolific invaders throughout the Greater Everglades Ecosystem in southern Florida, USA. We radio-tracked 188 adult and 168 juvenile Burmese Pythons to investigate arboreal microhabitat use and quantify the likelihood of observing Burmese Pythons in arboreal habitat. We observed adult pythons basking, resting, aggregating with other pythons, or brooding eggs in arboreal habitat, whereas we observed juvenile pythons resting, basking, or moving between tree limbs. Both adult and juvenile pythons were more likely to use arboreal habitat during the cooler months of December and January in southern Florida's dry season. A higher percentage of individual juvenile pythons than adult pythons used arboreal habitat, and the probability that a python occupied arboreal habitat decreased as its weight increased. Brazilian peppertrees ( Schinus terebinthifolia ) and live oaks ( Quercus virginiana ) supported heavier pythons. Information on the seasonal use of arboreal habitats by Burmese Pythons could improve the effectiveness of removal efforts by management agencies and enhance our understanding of the threats these snakes pose to vulnerable species, particularly arboreal-nesting birds.

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Case report: Observations on expulsions from 20 years of radiotransmitter implantation in adult Burmese pythons

Background Radiotelemetry as a research tool has advanced our understanding of snake behavior and ecology. However, surgical transmitter implantation can lead to health complications for study animals, including expulsion, which may also interfere with research objectives. Two implantation methods include intramuscular and coelomic placements, and we evaluate expulsion rates of transmitters using these methods in Burmese pythons ( Python bivittatus ) in southern Florida. Results From 2005 to 2024, we implanted 305 transmitters in 142 adult Burmese pythons, primarily using intramuscular implantation ( n = 221), then transitioning to include coelomic placement ( n = 84). There were no observations of transmitter-related mortality. Overall, 98.7% of transmitters were retained, with a 1.3% expulsion rate ( n = 4 transmitters). Expelled transmitters were only observed in intramuscularly implanted transmitters from 4 of 13 gravid females. Conclusions We observed no mortality related to transmitter implantation and few instances of transmitter expulsion, indicating that both intramuscular and coelomic implantation techniques are effective for monitoring adult pythons in the wild. However, there is some risk that females may expel transmitters when gravid, and this risk may be reduced when implanting transmitters intracoelomically. Our findings may be useful for studies of other large-bodied snake populations worldwide where radiotransmitter implantation is appropriate and logistically feasible.

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Coelomic foreign bodies in wild-caught Python spp. in the Greater Everglades Ecosystem, Florida, USA

Burmese pythons ( Python molurus bivittatus ) and African rock pythons ( Python sebae ) have established invasive populations in southern Florida, severely disrupting local ecosystems. We analysed necropsy data from 2,179 pythons captured between 2006 and 2022, revealing nine cases of coelomic foreign bodies, primarily consisting of bird beaks, which presumably entered the coelom following gastrointestinal perforations during prey consumption. Despite the presence of foreign bodies, most examined pythons exhibited no obvious health issues. These findings indicate that the consumption of prey with sharp morphological features, such as wading birds, may not impede the pythons’ survival or health significantly, thereby underscoring their adaptability as apex predators in the Greater Everglades Ecosystem.

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