Brown Treesnake detections on transects using potential attractants of live-mouse lures or fish-spray scent, Guam

Nocturnal visual encounter surveys for Brown Treesnakes were collected and summarized into 4 plain text files (csv format): CapturesLure, SurveysLure, CapturesScent, and SurveysScent. Capture files contain unique Passive Integrated Transponder (PIT) tag identification and measurements of snakes with dates and locations of capture. Survey files contain the dates of transect sampling and treatment application for each transect (Transect ID). Each project used a different type of attractant, either a live-mouse lures in snake traps or liquid fish fertilizer scented spray. Surveys were conducted in a 5-ha geographically closed population on Guam. Teams of two observers conducted night-time surveys from February 1 to March 31 2015 (live-mouse lure project) and November 1 to December 30 2016 (spray scent project). Visual surveys occurred along maintained 220-meter long transects at 8 meter spacing. Observers used headlamps to search for snakes in the vegetation or on the ground. Observers recorded snake identification, measurements, capture location, and date. Surveys began 30 minutes after sunset. For the lure study, transects either had no traps and live mouse lures (NTL) placed on them or had snake traps with live mouse lures (TL). Snake traps were modified minnow traps. Traps were suspended horizontally from natural vegetation 1-1.5 meter (m) off the ground. Within each trap, a chamber housed and protected a live-mouse attractant. Traps were deployed along the same transects where nocturnal visual surveys occurred. For the spray scent study, transects were either unsprayed (1) or sprayed either in the early evening before the night-time survey (2) or the previous day (3). Spray scent consisted of 500 milliliters of Alaska Fish Fertilizer and 14.74 liters of water and was sprayed along the entire length of a transect using a spray backpack over the course of four minutes to ensure a consistent application rate. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.