1. Figure captions Figure 1 Map of the topographic wetness index calculated using the FD8 (multiple flow direction) algorithm. The inset shows the location of the study area in Western Europe. Figure 2 Occurrence frequency of the four passerine species, all species (4-species), and all species but the Whinchat (3-species) observed in 64 transects. Figure 3 Probability of presence for the Whinchat and the 3-species (Yellow wagtail, Corn bunting and Reed bunting) represented as a logistic function of topographic wetness index. The TWI setting used here are D8 algorithm and 250m DEM. Table 1 Corrected Akaike information criterion (AICc) and Akaïke weight (w) values for logistic regressions between the occurrence of either individual bird species or the 3-species combination (Yellow wagtail, Corn bunting, Reed bunting) and topographic wetness indices including eigenvectors. We used four algorithms (D8, FD8, MD∞, SWI) and two resolutions (250m and 50m pixel). AICc 1 correspond to the null model with spatial eigenvectors and AICc 2 to the model with spatial eigenvectors including TWI. Bold values are used to indicate DAICc larger than 2. w1 is the weight of the null model and w2 the weight of the model including TWI. AUC (Area Under the Curve) and coefficient and standard error are indicated for candidate models selected by AIC.

2. WhinchatAICc 1 AICc 2  AICc (1-2) w 1 w 2 AUCCoef +-SE 250 mD881.8370.0311.800.001.000.821.780.56 FD881.8371.849.990.010.990.811.760.57 MD∞81.8370.2611.570.001.000.821.860.59 SWI81.8375.985.850.050.950.791.590.69 50 mD881.8372.569.270.010.990.811.760.59 FD881.8373.927.910.020.980.801.950.69 MD∞81.8372.759.080.010.990.811.780.60 SWI81.8380.840.990.380.62 Yellow Wagtail 250 mD883.7782.820.950.380.62 FD883.7782.001.770.290.71 MD∞83.7783.160.610.420.58 SWI83.7783.760.010.500.50 50 mD883.7785.37-1.600.690.31 FD883.7785.73-1.960.730.27 MD∞83.7785.47-1.700.700.30 SWI83.7785.63-1.860.720.28 Corn Bunting 250 mD886.3785.920.450.440.56 FD886.3784.911.460.330.67 MD∞86.3785.520.850.400.60 SWI86.3786.62-0.250.530.47 50 mD886.3786.010.360.450.55 FD886.3786.74-0.370.550.45 MD∞86.3786.070.300.460.54 SWI86.3787.87-1.50.680.32 Reed Bunting 250 mD871.3872.5-1.120.640.36 FD871.3873.12-1.740.710.29 MD∞71.3873.01-1.630.690.31 SWI71.3873.62-2.240.750.25 50 mD871.3873.35-1.970.730.27 FD871.3873.28-1.900.720.28 MD∞71.3873.31-1.930.720.28 SWI71.3873.62-2.250.750.25 Three species 250 mD885.2577.567.690.020.980.801.440.52 FD885.2575.499.760.010.990.811.750.58 MD∞85.2577.927.330.030.970.791.480.54 SWI85.2580.634.620.090.910.791.460.69 50 mD885.2583.821.430.330.67 FD885.2584.890.360.460.54 MD∞85.2583.951.300.340.66 SWI85.2584.760.490.440.56

3. Figure 1

4. Occurrence frequency Figure 2

5. Figure 3

6. Appendix 1 Distribution of transects across the study area (grey). Black dots: transects where at least one species was observed. Open dots: transect where no species was detected. Appendix 2 Scree plot of eigenvalues (%) extracted from the geographical distance matrix among 64 transects and expected under a broken-stick model. The three eigenvectors whose expected eigenvalues were higher than predicted values were selected. Appendix 3 Test of spatial autocorrelations for model residuals. Moran’s I test of complete GLMs residuals (D8 250m ) for each species and the value of Moran’s I. Tests were calculated for each ten distance classes. Appendix 4 Standard error boxplots for the topographic wetness indices at two DEM resolutions Appendix 5. Close-ups on one part of the study area illustrating the outputs of the 4 TWI algorithms at two DEM resolutions. High TWI scores indicate a high capacity of water retention. The inset shows the location of close-up in study area.

7. Appendix 1

8. Appendix 2

9. WhinchatY. WagtailCorn Bunting ClassDist (m) PMoran's IPMoran's IPMoran's I 13 7120.970.000.98<.0010.44-0.06 29 3640.140.100.54-0.040.970.00 314 9980.24-0.080.37-0.060.48-0.05 421 6840.27-0.070.52-0.040.76-0.02 529 2810.45-0.040.85-0.010.45-0.05 637 4230.59-0.030.90-0.010.570.04 746 0750.38-0.050.360.060.920.00 856 3700.37-0.060.55-0.040.29-0.07 968 5100.180.080.52-0.050.47-0.04 10116 4090.320.040.580.030.130.08 Reed BuntingAll species3 species ClassDist (m) PMoran's IPMoran's IPMoran's I 13 7120.780.020.48-0.050.720.02 29 3640.09-0.110.370.050.22-0.09 314 9980.910.000.970.000.9-0.01 421 6840.69-0.020.20-0.080.88-0.01 529 2810.24-0.070.42-0.050.52-0.04 637 4230.42-0.050.58-0.040.750.02 746 0750.140.100.860.010.970.00 856 3700.740.020.65-0.030.48-0.05 968 5100.41-0.040.740.020.55-0.04 10116 4090.750.010.340.040.170.06 Appendix 3

10. Appendix 4

11. Appendix 5 250m 50m