Table 1.

Heritability estimates (h²) for choice of breeding-colony size in cliff swallows

Category of birds	h2	SEM	P
Midparent, using offspring's natal-colony size as parental value
Male (n = 1,390)*	0.346	0.027	<0.0001
Female (n = 1,078)	0.377	0.032	<0.0001
Birds always using natal site (n = 1,654)	0.369	0.020	<0.0001
Birds using only nonnatal sites (n = 927)	0.326	0.036	<0.0001
Midparent, using parents' all known breeding-colony sizes
Male (n = 92)	0.279	0.235	0.24
Female (n = 58)	0.553	0.216	0.013
Single-parent, using parents' all known breeding-colony sizes
Male–father (n = 92)	0.714	0.472	0.13
Male–mother (n = 58)	0.312	0.407	0.44
Female–father (n = 92)	1.131	0.349	0.002
Female–mother (n = 58)	0.642	0.474	0.018
Midparent, 1997 cross-fostering, using offspring's natal-colony size as parental value
Males, not cross fostered, against birth colony (n = 143)	0.470	0.107	<0.0001
Males, cross fostered, against birth colony (n = 130)	0.536	0.102	<0.0001
Males, cross fostered, against rearing colony (n = 130)	−0.549	0.103	<0.0001
Females, not cross fostered, against birth colony (n = 114)	0.345	0.116	0.003
Females, cross fostered, against birth colony (n = 116)	0.295	0.122	0.017
Females, cross fostered, against rearing colony (n = 116)	−0.306	0.124	0.015
Midparent, 1998 cross-fostering, using offspring's natal-colony size as parental value (sexes combined)
Not cross fostered, against birth colony (n = 87)	0.375	0.061	<0.0001
Cross fostered, against birth colony (n = 88)	0.179	0.072	0.015
Cross fostered, against rearing colony (n = 88)	−0.117	0.068	0.086

^*Sample sizes differ in “Midparent, using offspring's natal-colony size as parental value,” because sex was unknown for some birds.