The Wilson Journal of Ornithology 123(1): 15-23, 2011 
HIGH APPARENT ANNUAL SURVIVAL AND STABLE TERRITORY 
DYNAMICS OL CHESTNUT-BACKED ANTBIRD (.MYRMECIZA EXSUL) 
IN A LARGE COSTA RICAN RAIN FOREST PRESERVE 
STEFAN WOLTMANN 1 - 2 AND THOMAS W. SHERRY 1 
ABSTRACT.—Antbirds (Thamnophilidae) are a diverse component of neotropical forest avifaunas, and are particularly 
vulnerable to population declines and extirpations in fragmented landscapes. We lack estimates of apparent survival and 
dispersal for the majority of species, despite their value in effectively managing populations of understory birds. We studied 
a population of Chestnut-backed Antbird ( Myrmeciza exsul ) from 2004 to 2009 in a large rain forest preserve in northern 
Costa Rica to generate estimates of apparent annual survival (tp). and breeding dispersal (i.e., movement from one breeding 
territory to another) in continuous forest. Estimates of <p (± SE) of adults based on weighted model averages were high 
(males: 0.794 ± 0.037; females: 0.798 ± 0.050) compared to independent juveniles (males: 0.629 ± 0.159; females: 0.629 
± 0.168). Detection (recapture/reobservation) probabilities (p) were higher for males (adults: 0.916 ± 0.034; juveniles: 
0.915 ± 0.049) than for females (adults: 0.544 ± 0.104; juveniles: 0.540 ± 0.115). Overall annual turnover (disappearing 
from the study area + territory switching) was comparable to other antbirds (~32%). Territory switching was rare, and 
generally limited to short movements to adjacent or nearby territories (mean distance moved = 372 m, range = 145-840 m, 
n = 9). Our results suggest Chestnut-backed Antbirds: (1) have relatively high adult annual survival, and (2) have limited 
breeding dispersal, even in a large, forested study area. Received 29 January 2010. Accepted 28 July 2010. 
Accurate and precise survival estimates are 
important to understand life history evolution and 
population demography (Martin 1996, Brawn et 
al. 1998), and also to protect and manage tropical 
forest birds in fragmented landscapes (Brawn et 
al. 1998). The question of whether tropical forest 
birds survive better than their temperate counter¬ 
parts has inspired considerable debate (e.g., Karr 
et al. 1990, Brawn et al. 1995, Johnston et al. 
1997), but remains unresolved at least partially 
due to questions regarding methodology and 
phylogeny (Brawn et al. 1995, Martin 1996, 
Sandercock et al. 2000). Estimates of apparent 
survival of birds are time-consuming and logisti¬ 
cal ly difficult to obtain in tropical forests, and are 
still lacking for the majority of tropical resident 
landbirds. 
Blake and Loiselle (2008) summarized pub¬ 
lished estimates of apparent annual survival (cp) 
for tropical birds, including 24 species of antbirds 
(Thamnophilidae), a uniquely neotropical species- 
rich family that is particularly vulnerable to forest 
loss and fragmentation. They noted considerable 
variation in cp for antbirds (Jc = 0.68; range = 
0.36-0.86), likely resulting from a combination of 
general uncertainty in methods, genuine species 
differences, and possibly regional variation within 
species. Methodological problems are implicated 
as detection methods involving reobservation and 
1 Department of Ecology and Evolutionary Biology, 
Tulane University, New Orleans, LA 07118, USA. 
2 Corresponding author; stefan.woltmann@gmail.com 
recapture of color-banded birds produce higher 
estimates of cp than recapture methods alone 
(Blake and Loiselle 2008). A typical cost of more 
accurate survival estimates derived from recap¬ 
ture/reobservation studies is the need to focus on 
one or a few species due to the intensity of effort 
required. 
The problem of estimating demographic pa¬ 
rameters such as survival of tropical birds is 
exacerbated by loss and fragmentation of forests, 
because demography is likely altered (Karr 1990). 
Patterns of species loss and decline in tropical 
fragmented landscapes are relatively well de¬ 
scribed (e.g., Stouffer and Bierregaard 1995, 
Sekercioglu et al. 2002, Sodhi et al. 2004) 
compared to demographic mechanisms. Under¬ 
story insectivores are particularly susceptible to 
landscape effects of deforestation and habitat 
fragmentation (Stouffer et al. 2006, Ferraz et al. 
2007, Stouffer and Bierregaard 2007) for reasons 
that are not clear (Turner 1996, Soderstrom 1999). 
The relevant mechanisms of declines have been 
difficult to identify, as studies using only 
presence-absence or relative abundance data 
cannot distinguish among different factors (e.g., 
decreased adult survival, increased nest predation, 
decreased dispersal). 
Forest-dwelling antbirds are particularly vul¬ 
nerable to declines and extirpations in fragmented 
landscapes (e.g., Ferraz et al. 2007, Stouffer and 
Bierregaard 2007, Van Houtan et al. 2007). A 
growing body of evidence suggests that non-forest 
impedes movements for many antbird species 
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