I have data on both predator (birds) and prey data (fish) simultaneous collected. For birds i have number of birds and for prey i have presence/absence (as factor) and then fish depth when fish are present. That means that when fish are absent depth is NA. I don't know if this is a stupid question but I was wondering if there is a way to run a model where i have number of birds ~ fish_presence + fish_depth if fish presence is 1.
Because I have zero inflated data, at the moment i am running two hurdle models: one with all data points with birds ~fish presence and other with data subset when fish are present with birds ~fish_length but i would like to have all these information in the same model.
Thank you in advance,
Ana