PriorCapL() function with CJS and/or RD Pradel Huggins p&c

[matthewklein]

Hello all,

I am attempting to use a robust design Pradel huggins p and c model to estimate survival and recruitment rates and derive estimates of lambda and abundance in eastern massasauga rattlesnakes. The capture history data has a total of 217 secondary occasions with 15 primary occasions. There is an unequal number of secondary occasions per primary occasion. The first 5 primaries encompass two consecutive months of nearly continuous secondary capture occasions, and the remaining primary occasions include between 3 and 5 secondary occasions. I used dot notation to specify when sampling did not occur or when a snake was censored as not available for capture (being held in captivity for some time). Additionally, sampling did not occur in 2020, so I included 2 secondary occasions coded with dot notation.

To test model assumptions, I built an annual capture history file representing the 15 primary occasions/years. Results from UCARE test2.ct indicate there is long term trap dependence in females. We suspect this is driven by their reproductive state. Gravid female snakes are much easier to detect than non-gravid females. These snakes have a reproductive interval of approximately 2 years, so we expect that if there is a pattern of detecting at individual female at higher rates every 2 years, its likely due to her being gravid.

Given that, I am wanting to reference previous captures of individuals from 2 years prior (t-2) as a predictor on detection in the current year (t). I have been trying to use the PriorCapL() function to achieve this without success. When I attempt to run a model, MARK pops up a blank screen and then fails to generate results, evidently failing to run the model altogether. I suspect it’s an issue with properly indexing prior capture occasions within the PriorCapL() function.

To better understand proper indexing of capture occasions, I referenced the single species occupancy chapter on the use of the PriorCapL() function and successfully replicated the model using PriorCapL() with the ‘NSO_SSoccupancy.inp’ data. The indexing there makes sense to me; you simply reference a previous capture occasion or a series of previous capture occasions.

I then attempted to use the PriorCapL() function with a simple CJS dataset that I created with 6 capture occasions, looking like this:

110111 25;
110010 20;
001101 30;
000111 30;
111000 15;
110101 10;
101010 15;

However, if I index in the same way as with the occupancy data, this also fails to run the model, like with my RD Pradel Huggins p and c model. Here is what my design matrix for p looks like using the PriorCapL function() on the example CJS data I provided:

6:p 1
7:p 1 PriorCapL(1,1)
8:p 1 PriorCapL(1,2)
9:p 1 PriorCapL(1,3)
10:p 1 PriorCapL(1,4)

At this rate, I think I am better off trying to figure out how to get the PriorCapL() function to work with this simple CJS data first before I bother trying to use it with my RD Pradel Huggins model. Hoping someone can provide some insight on what I am failing to see with indexing this CJS dataset relative to the occupancy dataset, and perhaps how this may translate to my robust design Pradel Huggins dataset.

Thanks!
Matthew