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Lunar effects on the fall migration of the Northern Saw-whet Owl (Aegolius acadicus ). Jackie Speicher, Lisa Schreffler, Dawn Konkoly and Darryl Speicher Pocono Avian Research Center, PO Box 4, Cresco, PA, 18326 USA. Methods
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Lunar effects on the fall migration of the Northern Saw-whet Owl (Aegolius acadicus). Jackie Speicher, Lisa Schreffler, Dawn Konkoly and Darryl Speicher Pocono Avian Research Center, PO Box 4, Cresco, PA, 18326 USA Methods The study area is located in Monroe County, PA (41.2268 N, 75.2425W). Field seasons were from 1 Oct to 15 Nov, 2000 – 2008. Mist nets and audio lure used nightly 1900 to 2300. Data were standardized as net-hours of effort. Capture rate information recorded as birds per net-hour (BNH). Calendar dates were recorded as 1-29 of the lunar cycle. Day 14 is Full and Day 29 is New). Capture rate (BNH) was analyzed for the three day period that encompasses each lunar event. • Results • Mean effort is 13.821 net-hour over nine field seasons. Net hours of effort through the entire lunar cycle was consistent. • Mean capture rate is 0.095 birds/net-hour over nine field seasons. • Significant differences between each of the four lunar events • (P=0.009, H=11.489, df=3). Discussion The lunar cycle has a strong influence on the migration of this owl. Each field season contained a complete lunar cycle, and with the exception of 2004, can be used independently to show these same results. In 2004, a total lunar eclipse during the full moon coincided with a change in capture rate. Highest capture rates following full moon and into first quarter moon, suggests migration interruption. Available light during the lunar cycle may be used in predator-prey interactions. Available light may also influence migratory logistics. Variations in both flight elevation and migratory path may result from the increased visual acuity provided by the full moon. Birds /Net Hour Lunar Cycle • Significant differences in capture rates between the full moon and the last quarter moon (P=0.003, H=8.75, df=1) and from the last quarter moon to the new moon (P=0.002, H= 9.319, df=1) Acknowledgments This research is funded by the sponsors of the Pocono Avian Research Center. Thanks to Skytop Lodge, Project OWlNet, Steve Clay and Dr. John Leiser.