Many thanks for the insights Jim. I should have considered telling Presence not to compute the VC matrix - thanks for pointing it out!

I've done as you suggested and run the default model, which does indeed complete. As for cutting down on the number of surveys per season: I worry that for my ultimate goal (see below), reducing the number of surveys may lead to the model not converging.

My goal: to obtain site-specific estimates of the probability of each state (averaged over all 25 seasons). I've attempted to follow the design that Gavin used (and you helped tweak) in this thread

http://www.phidot.org/forum/viewtopic.php?f=11&t=2007&p=12061#p12061. To that end, I have parameterized a model (i.e., design matrix in Excel) with a site-level factor (unique intercept for each site using a full-identity site covariate table). All "real" parms (i.e., "psi[from,to]") that share a "to" state would get a set of site parms (i.e., C1-C72 for all psi[m,1]). This results in 72*3=216 columns in the occupancy design matrix. I let this model run (with "don't compute VC matrix" checked) for a couple hours yesterday. It did not complete within that time (and I had to cancel the run to pack up for the day).

Given how computationally intensive it is, I'm curious whether you think this model has any chance of running on a standard PC. If not, do I have any options short of hard coding the analysis and running on some sort of HTC?

Edit: I'd also note that for my desired analysis, I'd need Presence to compute the VC matrix, adding to the challenge.

Many thanks as always Jim!

Best, Brendan