Your privacy, your choice

We use essential cookies to make sure the site can function. We also use optional cookies for advertising, personalisation of content, usage analysis, and social media.

By accepting optional cookies, you consent to the processing of your personal data - including transfers to third parties. Some third parties are outside of the European Economic Area, with varying standards of data protection.

See our privacy policy for more information on the use of your personal data.

for further information and to change your choices.

You are viewing the site in preview mode

Skip to main content

Table 1 Comparison of longitudinal between- and within-individual variation of migrating nightjars before and after ecological barriers

From: The spatial consistency and repeatability of migratory flight routes and stationary sites of individual European nightjars based on multiannual GPS tracks

 

Autumn

Spring

Start latitude

Stop latitude

    

Start latitude

Stop latitude

    

Baltic Sea

56

54

Estimate

Z

N

Effect size

54

56

Estimate

Z

N

Effect size

Between ind

87.9 ± 73.9

184.0 ± 105.8

0.38 ± 0.06

6.18***

68/34

1.12

93.0 ± 97.6

73.6 ± 50.9

− 0.02 ± 0.09

− 0.20

38/19

− 0.03

Within ind

9.4 ± 4.2

21.1 ± 10.1

036 ± 0.06

6.10***

52/26/11

1.31

63.4 ± 95.2

73.3 ± 79.5

0.30 ± 0.12

2.48*

32/16/7

0.51

BIV 2

5.1 ± 16.4

8.9 ± 21.2

0.35 ± 0.12

2.91**

98/49/34

0.47

31.0 ± 84.9

17.7 ± 53.1

− 0.13 ± 0.12

− 1.10

56/28/19

− 0.18

WIV 2

38.7 ± 21.5

82.5 ± 57.3

0.28 ± 0.07

3.98***

52/26/11

0.61

111.1 ± 192.4

125.9 ± 165.7

0.22 ± 0.14

1.58

32/16/7

0.38

The Alps

48

45

Estimate

Z

N

Effect size

45

48

Estimate

Z

N

Effect size

Between ind

225.8 ± 154.6

217.6 ± 166.3

− 0.07 ± 0.09

− 0.74

67/34

− 0.01

290.7 ± 204.5

152.8 ± 142.7

− 0.30 ± 0.06

− 4.88***

38/19

− 0.64

Within ind

23.4 ± 20.5

30.7 ± 25.5

0.13 ± 0.08

1.59

48/24/10

0.32

118.9 ± 104.7

58.9 ± 84.4

− 0.34 ± 0.20

− 1.72

32/16/7

− 0.48

BIV 2

13.0 ± 23.0

12.9 ± 30.2

− 0.16 ± 0.10

− 1.60

95/49/34

− 0.26

57.8 ± 99.3

54.3 ± 118.3

− 0.17 ± 0.13

− 1.33

56/28/19

− 0.24

WIV 2

72.5 ± 71.9

92.2 ± 94.1

0.04 ± 0.07

0.66

48/24/10

0.11

174.5 ± 176.1

108.4 ± 169.3

− 0.23 ± 0.17

− 1.34

32/16/7

− 0.35

Medi. Sea

43

33

Estimate

Z

N

Effect size

33

43

Estimate

Z

N

Effect size

Between ind

203.9 ± 160.0

219.9 ± 156.7

0.01 ± 0.09

0.16

66/33

0.38

353.3 ± 301.3

339.8 ± 246.7

− 0.03 ± 0.16

− 0.18

38/19

0.05

Within ind

37.7 ± 26.9

73.5 ± 50.9

0.32 ± 0.10

3.31***

48/24/10

0.71

207.8 ± 154.9

130.0 ± 135.8

− 0.47 ± 0.16

− 2.93**

32/16/7

− 0.74

BIV 2

12.4 ± 28.7

14.9 ± 33.4

0.14 ± 0.13

1.09

94/47/33

0.20

59.5 ± 60.0

76.7 ± 145.0

− 0.13 ± 0.10

− 1.31

56/28/19

− 0.26

WIV 2

111.1 ± 99.0

165.9 ± 125.5

0.39 ± 0.15

2.50*

48/24/10

0.47

329.1 ± 227.8

176.5 ± 226.2

− 0.68 ± 0.22

− 3.01**

32/16/7

− 1.00

Sahara Desert

31

12

Estimate

Z

N

Effect size

12

31

Estimate

Z

N

Effect size

Between ind

215.1 ± 157.0

257.4 ± 227.6

0.04 ± 0.12

0.31

65/33

0.41

543.0 ± 399.7

330.0 ± 256.9

− 0.27 ± 0.10

− 2.76**

40/21

− 0.64

Within ind

66.4 ± 52.2

77.4 ± 55.5

0.16 ± 0.13

1.19

46/24/10

0.25

38.6 ± 31.3

193.3 ± 144.0

0.71 ± 0.10

6.85***

32/16/7

2.15

BIV 2

16.3 ± 47.9

25.2 ± 31.3

0.25 ± 0.09

2.73*

92/47/33

0.56

59.2 ± 60.2

53.4 ± 52.2

0.08 ± 0.14

0.54

58/30/21

0.13

WIV 2

149.2 ± 144.3

135.8 ± 99.1

0.04 ± 0.08

0.48

46/24/19

0.06

54.8 ± 40.3

292.7 ± 199.4

0.53 ± 0.21

2.53*

32/16/7

0.75

Rainforest

5

− 4

Estimate

Z

N

Effect size

− 4

5

Estimate

Z

N

Effect size

Between ind

267.8 ± 205.4

245.3 ± 153.9

0.02 ± 0.07

0.30

64/32

0.22

332.6 ± 377.6

330.2 ± 251.8

0.25 ± 0.17

1.48

46/23

0.35

Within ind

102.7 ± 88.9

91.3 ± 56.3

− 0.10 ± 0.13

− 0.80

40/20/8

− 0.21

89.9 ± 72.1

77.1 ± 68.0

− 0.09 ± 0.09

− 0.99

32/16/7

− 0.21

BIV 2

17.4 ± 21.9

22.3 ± 20.9

0.16 ± 0.11

1.43

88/44/32

0.28

47.6 ± 113.2

28.4 ± 37.8

0.07 ± 0.13

0.54

64/32/23

0.10

WIV 2

175.7 ± 118.5

147.6 ± 123.0

− 0.09 ± 0.11

− 0.80

40/20/8

− 0.21

158.6 ± 157.3

136.7 ± 148.2

− 0.14 ± 0.14

− 1.02

32/16/7

− 0.23

  1. We investigate the longitudinal variation of routes at latitudes corresponding to the initiation and termination of the crossing of five potential barriers within the European-African migration system: Baltic Sea, the Alps, Mediterranean Sea, Sahara Desert, and tropical rainforest. We used two ways to quantify longitudinal variation, presented in km ± standard deviation. First, we measured the distance between focal track and group mean for two groups: between individual mean tracks (Between ind.) and withing individual tracks (Within ind.). Secondly, for each track we measured the distance to the nearest neighbouring track of other individuals (NN. BIV) and of the same individual (NN. WIV). We then tested the difference in the longitudinal variation at start and the stop latitudes using LMMs with random intercept for individual tracks nested within individual birds. Estimates are presented in km (log 10-scale) ± SE. Positive or negative values indicate an increase or decrease in longitudinal variation. Significant differences are highlighted in bold and the number of asterix represent the level (* < 0.05, ** < 0.01, and *** < 0.001). N-values corresponds to total number of measurements/tracks/individuals per test. For example, in the between-individual analysis of the Baltic Sea autumn crossing there are 68 measurements of 34 tracks (mean tracks for repeatedly tracked individuals) and in the within-individual analysis there are 52 measurements of 26 repeated tracks by eleven individuals. Effect size refers to Cohen’s d statistics
Back to article page

Movement Ecology

ISSN: 2051-3933