Table 4.

Analysis of variation in (A) probability to give birth to a male calf and (B) birth mass as a function of female mass and age (predicted from Trivers–Willard model; TWM) and male body mass (predicted from differential allocation hypothesis; DAH). (Data derive from 10 manipulations of the male segment of reindeer herds in Finland. The models are (A) a generalized mixed-effects model (GLMM) with a logistic link and (B) a linear mixed-effects model (LME), both models with two random factors (both male and female identity). Factors for which the 95% confidence interval does not overlap 0 (and hence can be considered significant) are bolded.)

			95% confidence interval
parameter	estimate	s.e.	lower limit	upper limit
(A) sex ratio
intercept	−6.5900	3.2576	−13.1052	−0.0748
female age	−3.5227	2.6560	−8.8348	1.7893
(female age)2	0.7943	2.2615	−3.7286	5.3173
female mass (September)	0.0225	0.0165	−0.0106	0.0555
male (sire) mass (Sep)	0.0097	0.0038	0.0021	0.0174
calf birth date (Julian date)	0.0273	0.0189	−0.0106	0.0652
(B) birth mass
intercept	4.4506	0.2349	3.9809	4.9204
calf sex (M versus F)	−0.0031	0.1385	−0.2802	0.2740
female age	0.1108	0.1968	−0.2828	0.5043
(female age)2	−0.4861	0.1536	−0.7934	−0.1789
female mass (Sep)	0.0051	0.0015	0.0020	0.0081
male (sire) mass (Sep)	0.0002	0.0005	−0.0008	0.0011
calf birth date (Julian date)	−0.0060	0.0014	−0.0087	−0.0032
female mass×calf sex	−0.0005	0.0005	−0.0014	0.0005
male mass×calf sex	0.0015	0.0016	−0.0018	0.0047