Table 2.

Results of GLMMs with participation in the exchange task as the dependent variable. Statistical parameters for the final model are given as well as factors entered into the model, degrees of freedom (df), F- and p-values. F- and p-values of excluded factors were taken from full models. Effects sizes are given for terms that remained in the final model. The results shown originate from S models; results written in italics originate from models containing the fixed factor “person”.

Factor	df	F	p	Factor level	Effect size
Final model	7	25.168	<0.001
Species	1	0.833	0.362	Crow	0.135
				Raven	1.590
Familiarity	1	43.350	<0.001	Long-term	−0.458
				Short-term	0
Season	2	24.933	<0.001	Pre-breeding	−0.132
				Breeding	0.284
				Post-breeding	0
Species × familiarity	1	5.236	0.022	Crow × long-term	1.101
				Raven × long-term	0
				Raven × short-term	0
Season × familiarity	2	22.604	<0.001	Pre-breeding × long-term	2.259
				Breeding × long-term	2.214
				Post-breeding × long-term	0
				Pre-breeding × short-term	0
				Breeding × short-term	0
				Post-breeding × short-term	0
Person (familiarity)	11	9.971	<0.001	A	6.780
				B	6.628
				C	−2.171
				D	4.680
				E	0
				D	−1.785
				F	−2.215
				G	−2.339
				H	−0.484
				I	−2.294
				J	−1.980
				K	−2.679
				L	0