Apparent survival rates of Cape Sugarbirds Promerops cafer at a breeding and a non-breeding site

Abstract

Reliable estimates of survival rates of southern African bird species are still rare. Yet precise information on life history traits of birds from this southern Mediterranean-type climate would help in evaluating the generality of global patterns of avian life history. We estimated annual survival of Cape Sugarbirds Promerops cafer at a breeding site and a non-breeding site, using capture-mark-recapture methods. Consistent between the two sites, annual survival was 0.54 for females and 0.64 for males, with an average of 0.62 at the breeding site. These estimates are close to estimates for more tropical African species, but at the upper range of estimates for northern-temperate passerines. With their small clutches, Cape Sugarbirds thus have a life history that is more similar to tropical passerines than to northern-temperate passerines. We found a high proportion of transient individuals at the non-breeding site, but not at the breeding site. This suggests that Cape Sugarbirds employ two strategies to cope with the spatially variable food supply during the non-breeding season. About half of the individuals appear to visit the same set of sites every year, whereas the others are more opportunistic and tend to visit different sites in different years.

Ostrich 2006, 77(3&4): 220–224