Research Question: Are red grouse (Lagopus lagopus scotica) a statistically significant proportion of raptor (bird of prey) diets?

I am planning on using a series of G-tests (determining whether there is a statistically significant difference between prey remains found in various raptor diets). However, I am aware that the Dunn's test is often used as a post-hoc for going into more detail here (in this context, pinpointing which prey items are more significant in occurrence than others.)

Can the Dunn's test therefore be used after running a G-test?

(If you wish to suggest better tests for this research question, then please feel free to do so!)