The spatial and temporal exploitation of anthropogenic food sources by common ravens (Corvus corax) in the Alps

Table 3 Model averaging outputs for the top models based on ∆AICc < = 6 for (a) the number of anthropogenic food sources (AFSs) visited (Poisson error distribution) for 81 individual ravens, and (b) the probability of an individual being at any AFS (binomial error distribution) for 79 individual ravens GPS-tagged for 2.75 years in the Austrian Alps

a) Number of AFSs visited (n = 376 estimates from 81 birds)
Log-transformed model estimates					Back-transformed estimates as % change
Fixed effects	Estimate	Unc. SE	95% CI	RVI	Estimate	Unc. SE	95% CI
Intercept	0.43	0.22	[0.00, 0.86]		53.53	− 78.17	[0.00, 135.71]
Juvenile^Ϯ	− 0.21	0.11	[− 0.38, − 0.03]	0.86	− 18.55	− 89.10	[− 31.65, − 2.94]
Wild-caught⁺	0.48	0.12	[0.24, 0.72]	1.00	61.67	− 87.78	[27.15, 105.56]
Spring^‡	0.00	0.11	[− 0.21, 0.21]	1.00	− 0.12	− 89.24	[− 19.16, 23.41]
Summer^‡	− 0.04	0.10	[− 0.23, 0.15]	1.00	− 3.85	− 90.44	[− 20.32, 16.02]
Winter^‡	0.35	0.09	[0.18, 0.52]	1.00	42.50	− 91.36	[20.25, 68.87]
2018^*	0.34	0.17	[− 0.22, 0.91]	0.15	41.16	− 83.35	[− 19.47, 147.43]
2019^*	0.40	0.18	[− 0.18, 0.98]	0.15	49.50	− 81.55	[− 16.16, 166.59]
2020^*	0.31	0.17	[− 0.34, 0.96]	0.15	36.10	− 83.03	[− 28.80, 160.17]
Male^ǂ	0.07	0.06	[− 0.13, 0.28]	0.29	7.66	− 93.55	[− 11.96, 31.66]
Fixes by days	− 0.04	0.05	[− 0.22, 0.14]	0.26	− 4.13	− 95.03	[− 19.84, 14.65]

b) Probability of being at any AFS (n = 369 estimates from 79 birds)
Logit-transformed model estimates					Back-transformed estimates as probability
Fixed effects	Estimate	Unc. SE	95% CI	RVI	Estimate	Unc. SE	95% CI
Intercept	− 2.42	0.29	[− 2.98, − 1.86]		0.08	0.57	[0.05, 0.13]
Juvenile^Ϯ	− 0.13	0.10	[− 0.40, 0.14]	0.36	0.07	0.53	[0.03, 0.15]
Wild-caught⁺	0.00	0.10	[0.39, 0.39]	0.26	0.08	0.53	[0.03, 0.19]
Spring^‡	1.16	0.12	[0.92, 1.40]	1.00	0.22	0.53	[0.11, 0.39]
Summer^‡	0.67	0.11	[0.45, 0.88]	1.00	0.15	0.53	[0.07, 0.27]
Winter^‡	0.60	0.14	[0.32, 0.87]	1.00	0.14	0.53	[0.07, 0.27]
2018^*	0.58	0.26	[0.07, 1.09]	1.00	0.14	0.56	[0.05, 0.32]
2019^*	− 0.04	0.28	[− 0.58, 0.50]	1.00	0.08	0.57	[0.03, 0.20]
2020^*	− 0.09	0.34	[− 0.75, 0.57]	1.00	0.07	0.58	[0.02, 0.22]
Male^ǂ	− 0.04	0.09	[− 0.39, 0.31]	0.26	0.08	0.52	[0.03, 0.18]

Reference categories: ϮAge class: ‘adult’, + origin: ‘captive-released’, ‡season: ‘autumn’, *year: ‘2017’, and ǂsex: ‘female’. Predictors with a relative variable importance (RVI) greater that 80% (i.e., 0.8) are highlighted in bold along with the respective confidence intervals (95% CI)

ISSN: 2051-3933