Parental investment asymmetries of a globally endangered scavenger: unravelling the role of gender, weather conditions and stage of the nesting cycle

Figures & data

Figure 1. Mean rate of copulations per week relative to the onset of incubation (week 0). The shaded area represents ± se.

Figure 2. Mean rate of delivery of material to the nest per week relative to incubation onset (week 0) (A). Mean nest arrangement rate (B) per week in relation to hatching week (week 0). The shaded areas in both graphs represent ± se.

Table 1. Results of the GLMMs for each behaviour recorded in Egyptian Vulture pairs (n = 20) in northern Spain.

Activity	Variables	AICc	ΔAICc	AICcW	K
Material delivery	Weather + Sex + Period	79.9	39	0.00	5
	Weather + Sex	65.6	24.7	0.00	4
	Weather + Period	67.5	26.6	0.00	4
	Sex + Period	44.6	3.7	0.15	2
	Weather	62.7	21.8	0.00	3
	Sex	40.9	0.0	0.70	1
	Period	44.6	3.7	0.11	1
	Null model	42.4	1.5	0.00	–
Nest arrangement	Weather + Sex + Period	136.1	31.4	0.00	5
	Weather + Sex	129.3	24.6	0.00	4
	Weather + Period	106.1	1.4	0.29	4
	Sex + Period	109.1	4.4	0.07	2
	Weather	124.7	20	0.00	3
	Sex	124	19.3	0.00	1
	Period	104.7	0.0	0.59	1
	Null model	107.6	2.9	0.00	–
Incubation/brooding	Weather + Sex + Period	987.5	2	0.06	5
	Weather + Sex	988.6	3.1	0.03	4
	Weather + Period	995.6	10.1	0.01	4
	Sex + Period	985.8	0.3	0.21	2
	Weather	996.8	11.3	0.00	3
	Sex	985.5	0.0	0.68	1
	Period	994.1	8.6	0.00	1
	Null model	993.9	8.4	0.00	–
Egg turning	Weather + Sex + Period	55.5	41.4	0.00	5
	Weather + Sex	43.9	29.8	0.00	4
	Weather + Period	52.9	38.8	0.00	4
	Sex + Period	17.5	3.4	0.15	2
	Weather	45.3	31.2	0.00	3
	Sex	14.1	0.0	0.79	1
	Period	19.7	5.6	0.05	1
	Null model	25	10.9	0.00	–
Nestling attendance	Weather + Sex + Period	800.1	2.9	0.13	5
	Weather + Sex	808.5	11.3	0.00	4
	Weather + Period	802.7	5.5	0.00	4
	Sex + Period	797.2	0.0	0.49	2
	Weather	811.3	14.1	0.00	3
	Sex	804.9	7.7	0.00	1
	Period	799.9	2.7	0.35	1
	Null model	807.8	10.6	0.00	–
Changeovers	Weather + Period	−41.8	0.0	0.83	4
	Weather	−33.7	8.1	0.02	3
	Period	−38.5	3.3	0.16	1
	Null model	−38.6	1.2	0.00	–
Food provision	Weather + Sex + Period	−18.6	28.6	0.00	5
	Weather + Sex	−34.7	12.5	0.00	4
	Weather + Period	−36	11.2	0.00	4
	Sex + Period	−40.1	7.1	0.01	2
	Weather	−41.7	5.5	0.03	3
	Sex	−45.8	1.4	0.24	1
	Period	−53.7	0.0	0.67	1
	Null model	−47.2	6.5	0.00	–
Nestling feeding	Weather + Sex + Period	−40.1	24.1	0.00	5
	Weather + Sex	−41.3	22.9	0.00	4
	Weather + Period	−53.5	10.7	0.00	4
	Sex + Period	−56.6	7.6	0.02	2
	Weather	−48.7	15.5	0.00	3
	Sex	−51.5	12.7	0.00	1
	Period	−64.2	0.0	0.97	1
	Null model	−58.86	5.3	0.00	–

Notes: Models are listed from the most saturated to the simplest, including combinations of variables. For each model, the differences of AICc values (ΔAICc) concerning the best model and the number of parameters (K) are shown, as well as their relative weight (AICcw). The best models are highlighted in bold.

Figure 3. Incubation and brooding investment (A) and nest attendance investment (B) per week in relation to hatching date (week 0). Values are expressed as a percentage of time. Shaded areas represent ± se.

Table 2. Results of GLMMs for the most parsimonious model for each breeding behaviour of Egyptian Vultures.

Values	Estimator	Se	t	P
	Material delivery
Intercept	0.15	0.24	0.61	0.56
	Nest arrangement
Intercept	0.35	0.17	2.07	0.06
Period	0.36	0.15	2.33	0.02
	Incubation/brooding
Intercept	51.22	10.90	4.78	<0.001
Factor (Sex) M	−14.82	6.64	−2.23	0.02
	Egg turning
Intercept	0.29	0.06	4.77	<0.001
Factor (Sex) F	−0.21	0.06	−3.20	0.002
	Nestling attendance
Intercept	−1.63	52.75	−0.03	0.97
Factor (Sex)	1.52	4.58	0.33	0.74
Period	−4.75	1.32	−3.58	<0.001
	Changeovers
Intercept	0.03	0.20	0.16	0.87
Temperature	0.11	0.06	−1.53	0.03
Relative humidity	5.14e^−04	0.01	0.32	0.74
Precipitation	2.93e^−05	9.96e^−05	0.29	0.65
Period	−6.38e^−03	0.01	0.45	0.001
	Food provisioning
Intercept	0.06	0.03	2.06	0.051
Period	0.01	0.01	2.31	0.02
	Nestling feeding
Intercept	0.34	0.05	7.34	<0.001
Period	−0.02	0.01	−3.68	<0.001

Note: Significant values are highlighted in bold.

Figure 4. The mean rate of egg turning (A) and mean changeover rate (B) per week in relation to hatching date (week 0). Temperature is expressed in degrees Celsius. Shaded areas in both graphs represent ± se.

Figure 5. Mean food provisioning rate (A) and mean nestling feeding rate (B) per week in relation to hatching date (week 0). Shaded areas in both graphs represent ± se.