MOVEMENT OF PARADISE SHELDUCK BETWEEN MOLT SITES: A JOINT MULTISTATE-DEAD RECOVERY MARK–RECAPTURE MODEL

Abstract

We used a mark–recapture analysis combining data from live recaptures of paradise shelduck (Tadorna variegata) at multiple banding sites with reported recoveries from birds shot by hunters to analyze the movement of paradise shelduck between molting sites. Our model allows survival, recapture, band recovery, and movement probabilities to depend on the possibly unknown location of the birds at the time live recaptures are made. Temporary emigration can be included in the model using unobserved states in which capture cannot occur. Survival probabilities varied through time and were different in the first year following banding compared to other years. At 2 of the sites, an estimated 30% of birds emigrated each year with evidence that the emigration was permanent. At the third site, an estimated 92% emigrated, but there was evidence that the emigration was temporary.