Table 3.

The results of linear mixed models comparing the SPCC coefficients of mew calls between pairs of birds according to their relative sex (same sex) and difference in a body size PC and the residuals from this body size PC for each of or the measurements of body mass, wing length and head to bill length. (Estimates and error terms are provided for final models with the random term bird identity (Wald Z = 6.96, p < 0.001).)

parameter	est.	s.e.	F-ratio	d.f.	p
same sex	0.001	0.003	0.270	1,111	0.605
body size PC	0.0005	0.005	0.010	1,133	0.919
body mass	−72.65	54.02	1.809	1,166	0.180
wing length	−127.31	93.55	1.852	1,16	0.175
head to bill length	−213.42	158.32	1.817	1,166	0.179