annual survival estimates

[Ross McGregor]

Hi everyone

I have calculated survival estimates for several species of tropical African birds using time constrained models (CJS and Barker). However, in order to make comparisons with other studies I need annual survival estimates. So I have calculated annual survival rates by adjusting the PIM accordingly. I have 7 primary encounter occasions spanning two years. As the data sets are quite small, some species that gave significant GOF and estimable parameters with phi(.) models did not produce estimable parameters for the annual models. However, those species that did give a survival parameter for each year had mean annual survival that was more or less the same as the time constrained models…except one. So, is the time constrained model essentially giving me the mean annual survival estimate? It appears to be doing this but then I can’t work out why one species is different. Is there another way to calculate annual survival from a survival estimate over two years? Any help or advice would be most welcome.

Cheers

Ross