Buckland (1980) discusses a solution to the frequently encountered problem of the Jolly-Seber model, which is that survival and birth rate estimates are found to be impossible (e.g. a negative birth rate). Jolly (1982) presents modifications, which by assuming constant survival and/or captures rates, gives a more parsimonious model, leading to more efficient estimators. Estimates assuming constant survival rates and probability of capture are calculated by selecting Open methods: Const. p and s Jolly Seber from the drop-down menu.
When this option is selected both the full Jolly-Seber and the constant survival and capture probability estimators are calculated.