SHORT COMMUNICATIONS 
159 
FIG. 1. Mean(± SE) capture rates (birds/net hr) of Northern Saw-whet Owls during the four lunar events (n - 178 individuals). 
Saw-whet Owls to examine if illumination was a 
factor in timing of migration. 
METHODS 
The study area was in Skytop, Pennsylvania (41° 
22' N, 75° 24' W, elevation 513 m) on the south 
side of West Mountain. It is a semi-permanently 
flooded cold deciduous forest dominated by eastern 
hemlock (Tsuga canadensis ), red maple (Acer 
rub rum), and rhododendron (Rhododendron caro- 
linensis). Northern Saw-whet Owls were not 
recorded at this location before this study and their 
status as residents remains unknown. 
The study period lasted from 1 October to 15 
November, 2000-2008. Each calendar day was 
assigned a corresponding lunar cycle code from 
one to 28 (NASA 2009). Day 1 represents the new 
moon, day 7 represents the first quarter moon, day 
14 represents the full moon, and day 21 represents 
the last quarter moon. 
Five mist nets (12 X 2.5 m X 60 mm mesh) were 
placed in a continuous line oriented in a north-south 
direction. A conspecific audio lure was positioned 
at the center of the net array. Nets were opened each 
evening from 1900 to 2300 hrs and mist nets were 
visited every 30 min. Individuals captured were 
weighed (g), measured, banded, and released using 
standard Bird Banding Laboratory protocols. Data 
were recorded for each encountered individual. 
We calculated the rate at which owls were 
captured each evening by dividing the total 
number of birds caught by each evening’s net 
effort. Data were pooled and averaged for each 
lunar day. Data were analyzed using ANOVA. 
RESULTS 
Each field season included all four lunar events 
(first quarter moon, full moon, last quarter moon, 
and new moon). No significant difference in net 
hours was evident between the four individual lunar 
events. No significant differences in capture rate 
were evident between each of the four lunar events 
(ANOVA: df = 3, P = 0.09) (Fig. 1). Mean capture 
rate was lowest during the new moon and full 
moon. The only exception to this pattern occurred 
in 2004 when there was an increase in captures 
associated with a total lunar eclipse. 
DISCUSSION 
Weather variables including precipitation, high 
winds, and cloud cover had a negligible effect on 
capture data during the 9-year study. However, 
there was a decrease in capture rates during the full 
and new moon relative to the last quarter moon. 
