[R] Poisson GLM warning message

[Anna Berthinussen]

Hi,

I receive the following warning message when I run a poisson GLM in R:

   "glm.fit: fitted rates numerically 0 occurred"

The model summary is shown below. The variable 'Species' consists of
counts of different species ranging from 0 to 4. I suspect this may
have something to do with the warning message but I'm not sure. Can
anybody help?

Thank you!

Anna


Call:
glm(formula = Species ~ Dist + Time + Alt + Elev.road + Noise +
      Cloud + Temp + Wind.sp + Water + Hab + Crossing, family = poisson,
      data = bats1)

Deviance Residuals:
        Min         1Q     Median         3Q        Max
-2.131083  -0.734566   0.005422   0.548956   2.186938

Coefficients:
                Estimate Std. Error z value Pr(>|z|)
(Intercept) -7.496e-01  6.642e-01  -1.128  0.25911
Dist         1.993e-04  1.233e-04   1.617  0.10593
Time        -4.753e-04  2.114e-03  -0.225  0.82206
Alt          2.042e-04  1.265e-03   0.161  0.87180
Elev.road    2.189e-03  1.960e-03   1.117  0.26418
Noise       -8.126e+01  4.528e+01  -1.795  0.07268 .
Cloud       -1.059e-03  2.274e-03  -0.466  0.64150
Temp         6.660e-02  4.051e-02   1.644  0.10017
Wind.sp     -7.553e-02  2.420e-02  -3.121  0.00180 **
WaterY      -6.919e-02  1.744e-01  -0.397  0.69162
Hab          1.200e-01  5.051e-02   2.375  0.01755 *
CrossingUnd  9.496e-02  1.214e-01   0.782  0.43420
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

(Dispersion parameter for poisson family taken to be 1)

      Null deviance: 253.49  on 239  degrees of freedom
Residual deviance: 206.59  on 228  degrees of freedom
AIC: 681.56

Number of Fisher Scoring iterations: 6