Radar quantifies migrant concentration and Dawn reorientation at a Great Lakes shoreline

Table 4 Results of Watson-Williams tests for difference in mean direction between night and dawn

Location	Trial(s)	df1	df2^a	F statistic	p-value	Difference ^b (degrees)
Inland	All trials	1	119,998	740	≤ 0.001	11.11
	Trial A	1	39,998	0	0.963	0.03
	Trial B	1	39,998	729	≤ 0.001	22.14
	Trial C	1	39,998	144	≤ 0.001	6.98
Shoreline	All trials	1	119,998	5048	≤ 0.001	30.34
	Trial A	1	39,998	1756	≤ 0.001	31.69
	Trial B	1	39,998	1772	≤ 0.001	35.13
	Trial C	1	39,998	1370	≤ 0.001	24.09
Over Water	All trials	1	119,998	17,098	≤ 0.001	51.84
	Trial A	1	39,998	7153	≤ 0.001	57.67
	Trial B	1	39,998	5292	≤ 0.001	58.74
	Trial C	1	39,998	4944	≤ 0.001	41.84

^aA random sample of 20,000 targets per biological period were included in each trial-specific test. Samples were pooled for the all-trial tests (n = 120,000). Tests were conducted using R package ‘circular’ [40]. ^b Difference is the change in mean flight direction between night and dawn. Positive values indicate a clockwise shift

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