Table 1.

Recording times and elicited responses. ‘Time recorded’ is time during which the animal was recorded in at least one observation camera, and ‘valid frames’ the sum of all frames multiplied by the number of crabs active (greater than 5 cm away from burrow) in the frame. After excluding insects, these are the 12 962 frames evaluated in the GLMM (table 2). Note that although terns only make up 16% of all observation time, they elicited 34% of all responses.

type (no.)	time recorded	valid frames	home runs	burrow descents
terns (14)	3 min, 08 s (25%)	2119 (16%)	51 (34%)	6
kites (20)	7 min, 01 s (57%)	9002 (66%)	66 (43%)	6
insects (20)	43 s (6%)	581 (4%)	15 (10%)	0
commuters (8)	1 min, 32 s (12%)	1841 (14%)	20 (13%)	2
total	12 min, 24 s	13 543	152	14