Mark resight questions

[AdrianSchiavini]

Hi, sorry if this question has been already answered, but couldn´t find an answer to it.

We are applying a mark resight methodology to assess free roaming dog abundance on the streets of a city (Ushuaia, Argentina). We use photographic records and natural marks from dogs to identify them.

The same segments of streets were surveyed five times over a 40 days period between late October and early December.

Maximum time between surveys was 2 weeks. We assume closure over this period.

We are only interested in abundance.

At every survey occasion, there are dogs that could not be photographed. We recorded them as a sighting, but unmarked.

Then we aim to apply the mark resight methodologies, specifically the zero truncated Poisson-log normal mark-resight model. Why?

In our understanding, the first survey occasion is the mark occasion, and the subsequent four survey occasions are the resight occasions.

Question 1. It is OK to consider the 4 survey occasions that happened after marking as primary sampling occasions?, or we should consider only onen primary occasion with 4 secondary occasions as in this post?:

viewtopic.php?f=1&t=3437&p=11210&hilit=resight#p11210

During the mark occasion, all sighted dogs were marked (photographed), except for those dogs that were not photographed.

The first survey, the marking occasion, we marked 182 dogs. They should be nj for the type of data requested.

Also, 20 dogs were recorded but couldn´t be photographed.

Question 2. How do we treat the 20 not photographed dogs during the mark occasion? We understand that we only consider the marked dogs from the “marking” survey. These 20 dogs should be not considered?

During the 4 resight surveys, we “marked and resighted” other 359 dogs.

Question 3. For the analysis, these should be entered as “Unmarked seen” (that is Tuj)?

Last, during the resight surveys 2 to 5, there were 58 dogs that couldn’t be photographed.

We don´t know if these dogs include dogs “marked” during the first occasion

Question 4. These 58 dogs, should be noted as “Unmarked seen” and added to the other 359 dogs that were observed during the resight surveys 2 to 5? We summed up them in the INP file to the “Unmarked seen” group.

With all this in mind, we build a INP file for MARK, in the understanding of 4 primary occasions.

Many thanks

Here it is the INP file
---------------------------------------------------------------------------------

/* Poisson log-normal mark-resight */
/* occasions=5 groups=1 */

/* Begin Input File */

01 1;
02 1;
+0 1;
+0 1;
01 1;
01 1;
+0 1;
04 1;
04 1;
+0 1;
+0 1;
+0 1;
+0 1;
+0 1;
03 1;
+0 1;
01 1;
+0 1;
03 1;
01 1;
04 1;
+0 1;
+0 1;
03 1;
02 1;
+0 1;
+0 1;
03 1;
+0 1;
+0 1;
+0 1;
02 1;
+0 1;
+0 1;
04 1;
02 1;
02 1;
+0 1;
03 1;
02 1;
02 1;
01 1;
+0 1;
01 1;
+0 1;
01 1;
+0 1;
01 1;
+0 1;
03 1;
+0 1;
01 1;
03 1;
03 1;
01 1;
03 1;
+0 1;
+0 1;
+0 1;
+0 1;
03 1;
02 1;
+0 1;
+0 1;
+0 1;
+0 1;
02 1;
03 1;
03 1;
03 1;
02 1;
+0 1;
+0 1;
+0 1;
01 1;
+0 1;
+0 1;
01 1;
+0 1;
+0 1;
01 1;
+0 1;
+0 1;
04 1;
02 1;
02 1;
01 1;
01 1;
02 1;
01 1;
01 1;
+0 1;
+0 1;
01 1;
01 1;
+0 1;
+0 1;
+0 1;
+0 1;
+0 1;
+0 1;
+0 1;
03 1;
01 1;
+0 1;
04 1;
02 1;
+0 1;
02 1;
02 1;
03 1;
04 1;
03 1;
03 1;
01 1;
01 1;
+0 1;
+0 1;
02 1;
+0 1;
03 1;
+0 1;
02 1;
02 1;
02 1;
01 1;
02 1;
01 1;
01 1;
+0 1;
+0 1;
+0 1;
04 1;
+0 1;
04 1;
04 1;
03 1;
02 1;
+0 1;
+0 1;
01 1;
+0 1;
+0 1;
04 1;
03 1;
02 1;
01 1;
03 1;
+0 1;
+0 1;
03 1;
+0 1;
02 1;
+0 1;
02 1;
01 1;
+0 1;
+0 1;
04 1;
01 1;
+0 1;
01 1;
01 1;
01 1;
+0 1;
+0 1;
+0 1;
+0 1;
+0 1;
+0 1;
+0 1;
02 1;
01 1;
02 1;
02 1;
03 1;
+0 1;
01 1;
03 1;
03 1;
+0 1;
+0 1;

Unmarked Seen Group=1;
417;

Marked Unidentified Group=1;
20;

Known Marks Group=1;
182;

/* End Input File */