High individual repeatability of the migratory behaviour of a long-distance migratory seabird

Table 1 Summary of models testing for effects of sex (female as a reference) on (A) departure from colony, (B) arrival at wintering area, (C) wintering longitude, (D) wintering latitude, (E) wintering latitude and (F) arrival at colony of common terns deployed with geolocators during 2016–2020

Model	estimate ± SE	df	t-value	p-value
A. departure from colony (days)^a
Intercept	233.73 ± 2.70	120.49	86.64	< 0.001
year_2017/18	4.16 ± 2.15	76.01	1.93	0.057
year_2018/19	12.82 ± 2.10	79.59	6.11	< 0.001
year_2019/20	11.36 ± 2.17	86.55	5.24	< 0.001
sex	13.19 ± 3.09	73.58	4.27	< 0.001
B. arrival at wintering area (days)^a
Intercept	243.86 ± 3.64	125.43	67.09	< 0.001
year_2017/18	7.13 ± 3.18	79.23	2.25	0.028
year_2018/19	12.60 ± 3.08	83.93	4.09	< 0.001
year_2019/20	14.75 ± 3.16	92.54	4.67	< 0.001
sex	13.60 ± 3.95	70.80	3.44	< 0.001
C. wintering area longitude^a
Intercept	-11.97 ± 1.17	1.17	69.83	< 0.001
year_2017/18	0.07 ± 0.13	0.13	70.01	0.555
year_2018/19	0.02 ± 0.12	0.12	70.06	0.875
year_2019/20	0.02 ± 0.13	0.13	70.12	0.131
sex	0.17 ± 0.57	0.57	78.94	0.769
D. wintering area latitude^a
Intercept	13.94 ± 1.55	92.06	9.02	< 0.001
year_2017/18	− 1.36 ± 0.46	70.11	− 2.96	0.004
year_2018/19	− 0.41 ± 0.45	70.49	− 0.90	0.370
year_2019/20	− 1.19 ± 0.48	71.06	− 3.99	< 0.001
sex	− 1.18 ± 1.68	130.31	− 0.70	0.480
E. departure from wintering area (days)^b
Intercept	85.41 ± 3.70	101.82	23.11	< 0.001
year_2017/18	3.93 ± 3.61	57.57	1.09	0.281
year_2018/19	3.01 ± 4.29	70.68	0.70	0.485
year_2019/20	− 1.92 ± 3.52	74.29	− 0.55	0.587
sex	5.59 ± 3.66	63.53	1.53	0.131
F. arrival at colony (days)^c
Intercept	105.06 ± 1.82	99.03	57.86	< 0.001
year_2017/18	4.44 ± 1.45	45.87	3.07	0.004
year_2018/19	5.81 ± 1.85	54.09	3.14	0.003
year_2019/20	6.08 ± 1.48	55.07	4.11	< 0.001
sex	1.38 ± 2.04	69.22	0.68	0.501

Between-year variation in the dependent variables was accounted for by adding year as a fixed effect to the models (2016/2017 as a reference). P-values ≤ 0.05 are presented in bold
^an = 138 tracks of 64 individuals (29 ♂ + 35 ♀)
^bn = 107 tracks of 60 individuals (27 ♂ + 33 ♀)
^cn = 105 tracks of 60 individuals (27 ♂ + 33 ♀)

ISSN: 2051-3933