Table 1.

Family-level conformance to Bergmann’s and Allen’s rules across global temperature gradients

	Conformity to Allen’s rule
	Slope in relative bill size			Slope in absolute bill size
Slope in body size	Non significant	Positive (Allen’s rule)	Negative	Non significant	Positive (Allen’s rule)	Negative
None	78 (40)	17	1	88 (36)	7	1
Negative (Bergmann’s rule)	5	2	1	5	0	3
Positive	1	2	0	1	2	0

Cell counts show number of families that conform or not to the rules. Of the slopes found non-significant for both criteria, the count of families with slope values nevertheless in the expected direction for both biological rules is shown in parentheses.