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Visual Surveys Rapid Response Saipan 2016


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Yackel Adams, A.A., and Lardner, B., 2020, Visual Survey Rapid Response Saipan 2016: U.S. Geological Survey data release,


Nocturnal visual encounter survey data conducted by 29 searchers over 17 transects obtained during a Brown Treesnake rapid response deployment to island of Saipan in 2016. Surveys took place in the vicinity of the Saipan airport and Dandan village (ca. 15.127°N, 145.735°E) from 06 January to 13 March 2016, 6–7 nights/week but with a break in surveying from 26 January through 21 February. During Brown Treesnake searches over 386.8 kilometers, we collected data on selected vertebrate taxa (lizards and small mammals, both potential snake prey) recorded from survey transects with similar vegetation structure (secondary forest dominated by the introduced leguminous tree Leucaena leucocephala; emergent trees were partially denuded from typhoon [...]


Point of Contact :
Amy A Yackel Adams
Originator :
Amy A Yackel Adams, Bjorn Lardner
Metadata Contact :
Amy A Yackel Adams
Publisher :
U.S. Geological Survey
Distributor :
U.S. Geological Survey - ScienceBase
SDC Data Owner :
Fort Collins Science Center
USGS Mission Area :

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VisualSurveys_RapidResponse_Saipan_2016.csv 103.62 KB


These visual encounter survey data were collected to document all snake and snake prey seen during a rapid response deployment to the island of Saipan for Brown Treesnake incipient population determination. Observers recorded all potential brown treesnake prey items seen, mostly because we want to characterize the prey populations in the (presumed) absence of snakes to better understand the snake’s ecosystem impact, should an introduced population become established. Additionally, we also believe that in the absence of ‘snake rewards’, offering other kinds of rewards (documented sightings of lizards, mammals, birds) help motivate observers to remain alert. We used this data set to assess if observer skills suffered from time-on-task during the 4 h of nightly surveys, because the sleeping lizards did not move over the course of an evening and the observers’ circadian rhythm was therefore not confounded with the targets’ circadian rhythm.



  • Fort Collins Science Center (FORT)
  • USGS Data Release Products



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Type Scheme Key
DOI doi:10.5066/P9QTSAHY

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