Survivorship of Permanent-Resident Birds in a Fragmented Forested Landscape

Abstract

Few studies have examined survivorship of animals in forest fragments differing in size, and none has used appropriate mark–recapture analysis techniques taking into account probability of recapture. Using Program MARK, a flexible mark–recapture software package, we estimated annual survival rates of four permanent‐resident woodland bird species over a 5‐yr period in a fragmented landscape. For Carolina Chickadees, White‐breasted Nuthatches, and Downy Woodpeckers, the probability of survival was related to site, with survival being highest in large woodlots, low in small woodlots, and either intermediate or lower in riparian woodlands. The presence of supplemental food had a positive influence on survivorship. Survivorship of the Tufted Titmouse was lower in years with heavy snow cover. There was some evidence for an age difference in apparent survival, with adult birds having higher survival rates. Overall, however, these age‐specific estimates had large variances or the differences disappeared when models were averaged, except in the chickadee, where young birds appeared to survive less well in forested river corridors. This last result was quite likely due, at least in part, to age‐specific dispersal, suggesting that river corridors function as important dispersal routes for young, transient birds of permanent‐resident species. These results suggest a strong additional cost of fragmentation: increased mortality. This cost has not been previously documented using modern mark–recapture analytical techniques.

Nuthatches eavesdrop on variations in heterospecific chickadee mobbing alarm calls

“…However, not all potential predators pose the same degree of threat to nuthatches. Because small birds like nuthatches may be severely food-limited in the winter as the result of low prey abundance and high energetic demands (22,(30)(31)(32), discriminating among different species of potential predators and mobbing dangerous predators most intensely may help conserve energy. Because they can differentiate among within-category variations of the chick-a-dee alarm calls that contain information about predator risk, nuthatches can selectively mob only the most dangerous predators.…”

Conserving Biodiversity in Urbanizing Areas: Nontraditional Views from a Bird's Perspective

“…Supplemental food provided at feeding stations can affect distribution, abundance, habitat selection, annual survivorship, sociality, and foraging behavior of birds, especially during winter months (Brittingham and Temple 1988;Desrochers et al 1988;Wilson 2001;Doherty and Grubb 2002;Atchison and Rodewald 2006). Effects of winter resources also can carryover to other seasons and influence the distribution of breeding birds, even though the resource may not be used at that time.…”

BETWEEN-YEAR SURVIVAL AND RANK TRANSITIONS IN MALE BLACK-CAPPED CHICKADEES (POECILE ATRICAPILLUS): A MULTISTATE MODELING APPROACH

“…Studies in several parid species have shown enhanced overwinter survival on food-supplemented sites (Jansson et al 1981, Källander 1981, Brittingham and Temple 1988, Doherty and Grubb 2002. Food resources may be particularly important during a limited number of harsh winter days, so perhaps having access to feeders at these critical times improved survival of subordinate birds.…”