Additional file 1: Appendix S1. negative log likelihood (-Loglike), number of parameters (K), Akaike’s Information Criterion (AIC), difference in AIC (Delta AIC) and AIC model weights (AICwt). List of candidate models representing alternative ways to model the detection process for eight grassland bird species. For each species, we selected the best detection model based on lowest AIC value (in bold).

Model / -Log Like / K / AIC / Delta AIC / AICwt
1. Cape Longclaw
1 / dens(.)p(.) / 220.36 / 2 / 444.72 / 4.083 / 0.092
2 / dens(.)p(Burning) / 217.32 / 3 / 440.64 / 0.000 / 0.708
3 / dens(.)p(Grazing) / 219.53 / 4 / 447.05 / 6.410 / 0.029
4 / dens(.)p(cover) / 219.40 / 3 / 444.79 / 4.154 / 0.089
5 / dens(.)p(avh) / 220.36 / 3 / 446.72 / 6.083 / 0.034
6 / dens(.)p(avh + cover) / 219.00 / 4 / 446.01 / 5.366 / 0.048
2. Wing-snapping Cisticola
1 / dens(.)p(.) / 163.73 / 2 / 331.46 / 7.345 / 0.016
2 / dens(.)p(Burning) / 161.79 / 3 / 329.59 / 5.467 / 0.041
3 / dens(.)p(Grazing) / 162.62 / 4 / 333.24 / 9.125 / 0.007
4 / dens(.)p(cover) / 163.37 / 3 / 332.75 / 8.627 / 0.009
5 / dens(.)p(avh) / 159.06 / 3 / 324.12 / 0.000 / 0.638
6 / dens(.)p(avh + cover) / 158.85 / 4 / 325.70 / 1.579 / 0.290
3. African Pipit
1 / dens(.)p(.) / 195.11 / 2 / 394.23 / 5.997 / 0.033
2 / dens(.)p(Burning.) / 195.04 / 3 / 396.08 / 7.844 / 0.013
3 / dens(.)p(Grazing) / 194.74 / 4 / 397.48 / 9.242 / 0.006
4 / dens(.)p(cover) / 194.91 / 3 / 395.82 / 7.583 / 0.015
5 / dens(.)p(avh) / 191.96 / 3 / 389.93 / 1.696 / 0.280
6 / dens(.)p(avh + cover) / 190.12 / 4 / 388.23 / 0.000 / 0.653
4. African Quailfinch
1 / dens(.)p(.) / 88.20 / 2 / 180.40 / 14.409 / 0.001
2 / dens(.)p(Burning) / 88.18 / 3 / 182.36 / 16.372 / 0.000
3 / dens(.)p(Grazing) / 80.90 / 4 / 169.80 / 3.805 / 0.129
4 / dens(.)p(cover) / 84.97 / 3 / 175.93 / 9.941 / 0.006
5 / dens(.)p(avh) / 88.09 / 3 / 182.18 / 16.191 / 0.000
6 / dens(.)p(avh + cover) / 79.00 / 4 / 165.99 / 0.000 / 0.864
5. Yellow-breasted Pipit
1 / dens(.)p(.) / 165.11 / 2 / 334.23 / 9.711 / 0.007
2 / dens(.)p(Burning) / 162.50 / 3 / 331.01 / 6.495 / 0.034
3 / dens(.)p(Grazing) / 163.37 / 4 / 334.73 / 10.215 / 0.005
4 / dens(.)p(cover) / 164.26 / 3 / 334.52 / 10.003 / 0.006
5 / dens(.)p(avh) / 161.82 / 3 / 329.64 / 5.128 / 0.068
6 / dens(.)p(avh + cover) / 158.26 / 4 / 324.51 / 0.000 / 0.880
6. Red-capped Lark
1 / dens(.)p(.) / 108.91 / 2 / 221.81 / 13.355 / 0.001
2 / dens(.)p(burning) / 102.58 / 3 / 211.17 / 2.711 / 0.193
3 / dens(.)p(Grazing) / 100.23 / 4 / 208.46 / 0.000 / 0.750
4 / dens(.)p(cover) / 104.90 / 3 / 215.80 / 7.340 / 0.019
5 / dens(.)p(avh) / 107.96 / 3 / 221.91 / 13.454 / 0.001
6 / dens(.)p(avh+cover) / 103.27 / 4 / 214.54 / 6.082 / 0.036
7. Zitting Cisticola
1 / dens(.)p(.) / 130.72 / 2 / 265.44 / 10.263 / 0.005
2 / dens(.)p(Burning) / 127.93 / 3 / 261.86 / 6.683 / 0.028
3 / dens(.)p(Grazing) / 125.99 / 4 / 259.98 / 4.803 / 0.072
4 / dens(.)p(cover) / 130.72 / 3 / 267.43 / 12.257 / 0.002
5 / dens(.)p(avh) / 126.71 / 3 / 259.41 / 4.240 / 0.096
6 / dens(.)p(avh + cover) / 123.59 / 4 / 255.18 / 0.000 / 0.797
8. Common Quail
1 / dens(.)p(.) / 133.43 / 2 / 270.86 / 1.492 / 0.171
2 / dens(.)p(Burning) / 132.17 / 3 / 270.34 / 0.967 / 0.223
3 / dens(.)p(Grazing) / 132.82 / 4 / 273.63 / 4.263 / 0.043
4 / dens(.)p(cover) / 132.91 / 3 / 271.83 / 2.459 / 0.106
5 / dens(.)p(avh) / 131.69 / 3 / 269.37 / 0.000 / 0.361
6 / dens(.)p(avh + cover) / 132.01 / 4 / 272.01 / 2.644 / 0.096