Supplementary table 1. (A) The effect on timing of migration when including ‘Latitude’ (Eilat,
Middle East and Jurmo, northern Europe), ‘Year’ (1984 – 2004) and ’Species’ (see the text) and all
three ’Migration phases’ (first 5%, 50% and 95% of the total number of trapped or observed
individuals) in a statistical model. We show opposing trends at different latitudes (significant
latitude * year interaction) with delayed passage through the Middle East, and advanced arrival in
northern Europe (see figure 2A). The results for the two interaction terms: “Latitude*Year” and
“Year*Species” reported in the text are slightly different from the results reported below as the
higher order significant interaction term “Latitude*Year*Migration phase” has been removed from
the models reported in the text. (B) The effect on timing of migration in the Middle East and
northern Europe including latitude, year, species, and all three migration phases, as well as African
spring NDVI (in relation to Middle East passage) and European spring NDVI (in relation to
northern Europe passage) in a statistical model. We show opposing effects of NDVI at different
latitudes (significant latitude * NDVI interaction) (see figure 2B). (C) Effect on migration duration
through Europe (number of days between the Middle East and northern Europe for the 50%
migration phase) when including species, European spring NDVI and all three migration phases in a
statistical model. We show an overall significant effect of NDVI on migration duration, with better
conditions decreasing migration duration. All models were fitted as statistical models including all
independent variables and their interactions, using linear mixed models (proc MIXED; SAS 2000)
and with migration phase as the repeated factor. We performed backward elimination procedures
removing all insignificant variables except when higher-level interaction was significant.
A
B
Parameter
Timing of migration
Latitude
Year
Species
Migration phase
Latitude * Year
Latitude * Species
Latitude * Migration phase
Year * Species
Year * Migration phase
Species * Migration phase
Latitude * Year * Migration phase
Error
Timing of migration
Latitude
Year
Migration phase
NDVI
Species
Latitude * Migration phase
Latitude * Year
Latitude * NDVI
Latitude * Species
Year * Migration phase
Migration phase * NDVI
Migration phase * Species
Year * NDVI
df
F
P
1
1
4
2
1
4
2
4
2
8
2
550
16.13
4.58
3.89
0.51
16.12
0.01
5.52
3.89
0.51
0.00
5.52
< 0.0001
0.0329
0.0040
0.6000
< 0.0001
0.9999
0.0042
0.0040
0.5999
1.0000
0.0042
1
1
2
1
4
2
1
1
4
2
2
8
1
0.21
3.68
0.72
0.98
1.96
3.77
0.21
7.76
0.00
0.72
0.89
0.00
0.99
0.6443
0.0559
0.4874
0.3217
0.1000
0.0238
0.6439
0.0056
1.0000
0.4874
0.4107
1.0000
0.3207
C
Year * Species
Latitude * Year * Migration phase
Error
2
2
441
3.77
3.77
0.0999
0.0237
Migration duration
Species
Migration phase
Species * Migration phase
NDVI
Error
4
2
8
1
188
87.08
27.56
6.64
5.21
< 0.0001
< 0.0001
< 0.0001
0.0236