is psi the prob of a site being occupied or the proportion..

[nathamu]

Hello,

I have a very simple question, I am working on single season single species, and I got confused about what psi is... my understanding is that psi is the probability of a site being occupied by the target species, but I have read so many papers reporting psi as the proportion of sites occupied by the target species... so now I don't know... can anyone clarify this to me please???

[bacollier]

Hello,

I have a very simple question, I am working on single season single species, and I got confused about what psi is... my understanding is that psi is the probability of a site being occupied by the target species, but I have read so many papers reporting psi as the proportion of sites occupied by the target species... so now I don't know... can anyone clarify this to me please???

nathamu,
Have a look at MacKenzie et al. (2006), Chapter 2 (page 25) 2nd paragraph beginning with the sentence "Note that there is an important distinction between "proportion of an area occupied" and "probability of occupancy." The following paragraph will answer your question.

bret