Table.1 Factor loadings of 15 acoustic variables on the 4 principal components in the Caprimulgus affinis complex. Eigenvalues and percentage of variance explained by the respective components are given at the bottom of the table

F1

0.788

0.341

0.110

 − 0.261

F2

0.129

0.905

 − 0.239

0.202

F3

0.940

0.194

0.212

0.156

F4

0.080

0.595

0.582

 − 0.440

F5

0.693

0.467

0.384

 − 0.315

F6

0.941

0.194

0.217

0.146

F7

0.129

0.905

 − 0.239

0.202

DF1

0.910

 − 0.084

 − 0.060

0.365

DF2

0.826

 − 0.097

 − 0.001

0.491

DF3

0.847

 − 0.338

0.352

0.025

DT1

 − 0.636

 − 0.046

0.621

0.417

DT2

0.634

 − 0.321

 − 0.325

0.224

DT3

 − 0.660

0.566

0.190

0.349

DT4

 − 0.688

0.554

0.159

0.333

DT5

 − 0.230

 − 0.578

0.641

0.227

Eigenvalue

6.906

3.599

1.795

1.372

Variance explained

46.0%

24.0%

12.0%

9.1%

F (ANOVA)

8606

6604

15.0

15.1

Significance (ANOVA)

P < 0.001

P < 0.001

P < 0.001

P < 0.001

Degrees of freedom (ANOVA)

85

85

85

85