Is the breeding behaviour of nesting seabirds influenced by the presence of a predatory reptile—the tuatara?

Figures & data

Figure 1 The proportion of nights during the study period that burrows classed with a resident tuatara and those with random visits by tuatara were recorded as having a tuatara present.

Table 1 List of burrows monitored over five fieldtrips (only nine burrows in January 2011 due to faulty logger).

Table 2 Selection results for models testing for the effects of year, month, night, temperature measured at midnight in °C, moon phase, resident tuatara at burrow (tuat.res) and infrequent visits by tuatara (tuatara) on first arrival at burrow (measured as time to the nearest minute).

Model	K	AICc	∆AICc	Weight
Month + (1|bird)	2	7827.816	0.00	0.57
Month + tuatara + (1|bird)	3	7830.438	2.62	0.15
Month + temperature + (1|bird)	3	7831.444	3.63	0.09
Tuatara + temperature + month + moon + (1|bird)	4	7832.06	4.24	0.07
Tuatara + temperature + month + (1|bird)	4	7833.068	5.25	0.04
Month + tuat.res + (1|bird)	3	7833.457	5.64	0.03
Month + year + (1|bird)	3	7835.470	7.65	0.01
tuat.res + temperature + month + (1|bird)	4	7836.093	8.28	0.01
Tuatara + month + year + (1|bird)	4	7837.101	9.29	0.01
Month + year + temperature + (1|bird)	4	7839.117	11.30	0.00

All models except the model testing for an effect of ID alone (generalised linear model without random effect) are generalised linear mixed models (see Methods for details) controlling for individual heterogeneity via an individual random effect (bird). Only the top 10 models are displayed and the grey box highlights the two models, which explain 79% of the overall AIC_c (Akaike's information criterion corrected for small sample size) weight and which were within three points of the best model (∆AIC_c).

Table 3 Results for models testing for the effects of year, month, night, temperature measured at midnight in °C, first arrival time, resident tuatara at burrow (tuat.res), infrequent visits by tuatara (tuatara) and mate on activity at the burrow (measured as time to the nearest minute) in September, October/November and January.

Month	Model	K	AICc	∆AICc	Weight
September	(1|bird)	1	705.848	0.00	0.44
	Mate + temperature + (1|bird)	3	706.563	0.72	0.31
	1st.arrival + (1|bird)	2	707.943	2.09	0.15
	tuat.res + (1|bird)	2	711.551	5.70	0.03
October/November	1st.arrival + (1|bird)	2	2684.608	0.00	0.87
	tuat.res + 1st.arrival + (1|bird)	3	2690.926	6.31	0.04
January	tuatara*year + (1|bird)	2	2202.638	0.00	0.50
	tuat.res*year + (1|bird)	2	2202.638	0.00	0.50
	tuatara + (1|bird)	2	2226.190	23.55	0.00

All models except the model testing for an effect of ID alone (generalised linear model without random effect) are generalised linear mixed models (see Methods for details) controlling for individual heterogeneity via an individual random effect (bird). Only the top model(s) plus next best model for comparison are displayed, and the grey box highlights the top models, which explain the majority of the overall AIC_c (Akaike's information criterion corrected for small sample size) weight and which were less than three points in ∆AIC_c.

Figure 2 Time spent by fairy prions at the burrow (minutes) in relation to temperature (°C).

Figure 3 Time spent by fairy prions at the burrow (minutes) in relation to time of first arrival at the burrow in September and October/November.