To dare or not to dare? Risk management by owls in a predator-prey foraging game.

Keren Embar, Ashael Raveh, Darren Burns and Burt P. Kotler

Ben Gurion University of the Negev, Blaustein Institutes for Desert Research, Mitrani Department of Desert Ecology, Sde Boker Campus, Midreseht Ben-Gurion 84990 Israel.

Corresponding author: Keren Embar

Ben Gurion University, Institute for Desert Research, Mitrani Department of Desert Ecology, Midreseht Ben-Gurion 84990 Israel. Phone: 08-659-6785 Fax: 08-659-6772 E-mail:

Online Resource 1

Table 1.a. Analysis of Mixed Effect model for owl attacks, with N=42, Multiple R2=0.623.

Source / Effect / Sum-of-Squares / df / Mean-Square / F-ratio / P
OWL_ID / Random / 22.842 / 2 / 11.421 / 2.085 / 0.141
OWLSTATE / Fixed / 52.532 / 1 / 52.532 / 9.593 / 0.004
BUSHTYPE / Fixed / 39.847 / 1 / 39.847 / 7.276 / 0.011
MICROHABITAT / Fixed / 100.595 / 1 / 100.595 / 18.369 / 0.000
BUSHTYPE * OWLSTATE / Fixed / 9.089 / 1 / 9.089 / 1.660 / 0.207
MICROHABITAT * OWLSTATE / Fixed / 43.603 / 1 / 43.603 / 7.962 / 0.008
MICROHABITAT * BUSHTYPE / Fixed / 0.143 / 1 / 0.143 / 0.026 / 0.873
MICROHABITAT * BUSHTYPE* OWLSTATE / Fixed / 0.660 / 1 / 0.660 / 0.120 / 0.731
Error / 175.242 / 32 / 5.476

Table 1.b. Analysis of Mixed Effect model for owl foraging time, with N=42, Multiple R2=0.546

Source / Effect / Sum-of-Squares / df / Mean-Square / F-ratio / P
OWL_ID / Random / 5.0E+04 / 2 / 2.5E+04 / 3.846 / 0.032
OWLSTATE / Fixed / 1.5E+04 / 1 / 1.5E+04 / 2.275 / 0.141
BUSHTYPE / Fixed / 1.7E+04 / 1 / 1.7E+04 / 2.606 / 0.116
MICROHABITAT / Fixed / 1.3E+05 / 1 / 1.3E+05 / 19.350 / 0.000
BUSHTYPE * OWLSTATE / Fixed / 1.6E+03 / 1 / 1.6E+03 / 0.243 / 0.625
MICROHABITAT * OWLSTATE / Fixed / 3.1E+04 / 1 / 3.1E+04 / 4.768 / 0.036
MICROHABITAT * BUSHTYPE / Fixed / 2.4E+03 / 1 / 2.4E+03 / 0.365 / 0.550
MICROHABITAT * BUSHTYPE* OWLSTATE / Fixed / 2.2E+03 / 1 / 2.2E+03 / 0.335 / 0.567
Error / 2.1E+05 / 32 / 6.5E+03

Table 2.a. Analysis of Variance table for gerbil Giving Up Density with N=479 (trays), and multiple R2=0.036

Source / Sum-of-Squares / df / Mean-Square / F-ratio / P
OWLSTATE / 3.822 / 1 / 3.822 / 7.222 / 0.007
BUSHTYPE / 5.269 / 1 / 5.269 / 9.958 / 0.002
BUSHTYPE * OWLSTATE / 0.371 / 1 / 0.371 / 0.701 / 0.403
Error / 251.349 / 475

Table 2.b. Analysis of Variance table for time the gerbils foraged in trays, with N=79 (trays), and Multiple R2=0.035

Source / Sum-of-Squares / df / Mean-Square / F-ratio / P
OWLSTATE / 9.5E+04 / 1 / 9.5E+04 / 0.148 / 0.701
BUSHTYPE / 1.2E+06 / 1 / 1.2E+06 / 1.869 / 0.176
BUSHTYPE * OWLSTATE / 5.1E+05 / 1 / 5.1E+05 / 0.798 / 0.375
Error / 4.8E+07 / 75 / 6.4E+05