analysis of multi-source but limited timespan data

[Crex]

Hi
Somewhat complicated question (for me) which I shall try, as recommended, to keep as straightforward as possible in explanation.
I’m attempting to work out survival estimates and population sizes for mustelids on a small island overwinter (ergo no immigration or emigration by any means other than death). There are only small populations so not a huge dataset, but there is both recapture from trapping data and ‘recapture’ from radio telemetry (but not all individuals are collared), as well as recovery – mostly from collared individuals who’ve died and been located. However, there were only two actual trapping sessions with intervals after each so there’s not enough data to run a Burnham/Barker model (which would have been ideal as they appear to cover all my data sources). I can see there are simpler models but these appear to require me losing data which I’m reluctant to do. I also fear that the small samples may make it harder for anything to run in the programme so, is anyone willing to suggest options that will make best use of the data I have?
And, but I guess much less importantly, because it’s an island there are no complications with emigration as the whole area is the capture area so how could I set F=1 if I could run a, for example, Barker model (I cannot find an option to do this)?
Cheers