Table 2.

Factors affecting urban commonness of bird species in Oslo, with subset of urban sites from the highly urbanized inner city centre only

Predictor	df	F	P
Frequency in surrounding sites	1	101.78	<0.0001
Habitat type	3	19.71	<0.0001
Migration	1	1.56	0.22
Nest location	3	7.04	0.0003
Brain mass	1	0.10	0.75
Residual body mass	1	5.89	0.018

Results from ANCOVA (summarized with a sequential sum of squares) showing associations between the frequency of occurrence of bird species (N = 90) in urban sites (N = 22) in Oslo and six predictor variables (frequency of occurrence in surrounding sites, habitat type, migration, nest site and relative brain mass [i.e. ln-transformed brain mass and residual body mass]). Significant values (P < 0.05) are in bold. See Additional file 1: Table S4 for full results from summarization of PGLS model.