Mod1 <- glmer.nb(Nb_pt_nv ~ Substrate + (1|ID_bird), data = data).
Mod2 <- glmer.nb(Nb_fix ~ Bathy_topo + (1|ID_bird), data=data).

Mod3 <- glmer.nb(Nb_pt_nv ~ Substrate:Bathy_topo + (1|ID_bird), data = data)

Generalized linear mixed model fit by maximum likelihood (Laplace Approxim tion) ['glmerMod']
 Family: Negative Binomial(2.4986)  ( log )
Formula: Nb_pt_nv ~ Substrate:Bathy_topo + (1 | ID_bird)
   Data: F1_CB_all

     AIC      BIC   logLik deviance df.resid
  7926.9   8000.7  -3949.4   7898.9     1427

Scaled residuals:
    Min      1Q  Median      3Q     Max
-1.2629 -0.7275 -0.2739  0.3640  7.4995

Random effects:
 Groups  Name        Variance Std.Dev.
 ID_bird (Intercept) 0.06609  0.2571
Number of obs: 1441, groups:  ID_bird, 10

Fixed effects:
                            Estimate Std. Error z value Pr(>|z|)
(Intercept)                 2.54474    0.17982  14.151  < 2e-16 ***
Sub1:Topo_Shelf            -1.36434    0.18114  -7.532 5.00e-14 ***
Sub2:TopoShelf             -0.96808    0.18090  -5.351 8.73e-08 ***
Sub3:TopoShelf             -1.08011    0.16919  -6.384 1.72e-10 ***
Sub2:Topo_Shelf_break      -0.88011    0.62247  -1.414 0.157393
Sub3:Topo_Shelf_break      -0.57702    0.23998  -2.404 0.016198 *
Sub4:Topo_Slope            -0.56675    0.16678  -3.398 0.000678 ***
Sub1:Topo_Slope            -1.23023    0.87412  -1.407 0.159308
Sub2:Topo_Slope            -0.76328    0.21249  -3.592 0.000328 ***
Sub3:Topo_Slope            -0.62372    0.16481  -3.785 0.000154 ***
Sub5:Topo_Slope            -0.58459    0.20093  -2.909 0.003620 **
Sub4:Topo_Abyss            -0.07263    0.26459  -0.275 0.783688

Mod4 <- glmer.nb(Nb_pt_nv ~ Substrate * Bathy_topo + (1|ID_bird), data=data)

Generalized linear mixed model fit by maximum likelihood (Laplace Approximation) ['glmerMod']
 Family: Negative Binomial(2.4986)  ( log )
Formula: Nb_fix ~ Bathy_topo * Substrate+ (1 | ID_bird)
   Data: F1_CB_all

     AIC      BIC   logLik deviance df.resid
  7926.9   8000.7  -3949.4   7898.9     1427

Scaled residuals:
    Min      1Q  Median      3Q     Max
-1.2629 -0.7275 -0.2739  0.3640  7.4995

Random effects:
 Groups  Name        Variance Std.Dev.
 ID_bird (Intercept) 0.06609  0.2571
Number of obs: 1441, groups:  ID_bird, 10

Fixed effects:
                                  Estimate Std. Error z value Pr(>|z|)
(Intercept)                        1.52160    0.10993  13.841  < 2e-16 ***
Topo_Shelf_break                   0.50309    0.18218   2.762  0.00575 **
Topo_Slope                         0.45639    0.05822   7.839 4.53e-15 ***
Topo_Abyss                         0.95051    0.23844   3.986 6.71e-05 ***
Sub1                              -0.34120    0.11644  -2.930  0.00339 **
Sub2                               0.05506    0.10928   0.504  0.61439
Sub3                              -0.05697    0.05676  -1.004  0.31555
Sub5                               0.07263    0.26456   0.275  0.78367
Topo_Slope:Sub1                   -0.32229    0.86530  -0.372  0.70955
Topo_Shelf_break:Sub2             -0.41511    0.64224  -0.646  0.51805
Topo_Slope:Sub2                   -0.25159    0.17062  -1.475  0.14033
Topo_Slope:Sub5                   -0.09048    0.29375  -0.308  0.75808