Table 1.

Results of the generalised linear model with the number of sub-species per species as independent variable

	Estimate ± SE	Deviance (df = 1)	P value
Minimal adequate model
Migratoriness	−0.10 ± 0.08		0.23
Non-breeding habitat	−0.16 ± 0.19		0.39
Breeding habitat	0.06 ± 0.04		0.17
Species age	−0.01 ± 0.007		0.11
Migratoriness × non-breeding habitat	0.27 ± 0.12	4.92	0.03
Separate models
Non-breeding habitat
Migrants	0.42 ± 0.15	7.39	0.007
Partial migrants	0.13 ± 0.10	0.07	0.79
Non-migrants	−0.21 ± 0.21	1.07	0.30

Non-significant interaction terms were removed. P values for the main effects were obtained by using the parameter estimate divided by its standard error as the test statistic. Also shown are the results of separate models for each category of migratoriness.