Error trying to model multiple season model. na.action = NULL?

[Romi Diego]

Hi everyone!

I'm trying to model a dataset of camera traps of three winters (3 seasons) with multiple season occupancy models. My objetive is to see if there are diference in the use of habitat by a wild cat of the zone and if there are colonization and extintion dinamic. I have 3 site covariables which are vegetation cover, distant to water and distant to places with human disturbance. And one site-seasonal covariable which is effort (since every season and every site had diferent effort). I have no observation covariable. I made my unmarked dataframe charging every dataset separately and then using de function unmarkedMultFrame as follows:

umf <- unmarkedMultFrame(y=Det_Hist2, siteCovs=sitecovs, obsCovs=NULL, numPrimary=3, yearlySiteCovs=seasoncovs)

Until there, I had no problem; but when I try to run the models, for example, the null model, then I get the following error:

m.null<-colext(~1~1~1~1, data=umf)
Error in model.frame.default(psiformula, siteCovs, na.action = NULL) :   object is not a matrix

To understand better this models (since I'm new in all of this) before I get into multi season models I took one season of my data and modeled with single season models using similar steps (but with the correspondents functions) and I didn't get this error, so I don't understand what I'm doing wrong here.

I would really apreciate your help.

Romina