detection probability and missing values

[giulia.santulli]

Hello,
Sorry but I didn't mange to find this information in the forum.
I'm wondering how missing values in detection histories are "interpreted" in the detection probability estimation. I'm using a multi seasons model, and I have two secondary periods for each year.
So inside one year I have the following options of detection ( where "." = missing value):
..
0.
.0
1.
.1
01
10
11

How do the model use the 0. / .0 / 1. / .1 information for detection probability? Is it discarded or is it used in the estimation?
I'm asking this because I need to demonstrate random movement in and out of each site, and obviously it makes a big difference if for example a "1." in detection history is interpreted as a "10" in detection estimation or is simply ignored by the algorithm.
Thanks in advance

Giulia