140 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 
Aramides Wood Rails, a poorly known neotropical premontane rain forest averaging ~3 m of rain 
genus with several globally threatened members. 
Breeding of Brown Wood Rails coincided with 
peak rainfall and, although the clutch size of four 
eggs is relatively small compared to other Rallidae 
(Taylor 1996), nesting success was relatively high 
(66%). However, post-hatching mortality of young 
may also be high; at least one adult that successfully 
hatched young re-nested 14 days later, suggesting 
the young had been depredated. 
At least two adults contributed to incubation, 
brooding, and post-hatching care. We also observed 
and/or heard a second individual accompanying a 
radio-marked bird throughout the 7-month tracking 
period. We did not observe more than two adults 
together at any time. These preliminary data 
suggest Brown Wood Rails may form long-term, 
socially monogamous pair bonds. 
The home range size of 9.0-13.5 ha (95% 
kernel and MCP, respectively) for Brown Wood 
Rails is intermediate relative to other terrestrial 
rain forest species. Home range of the Chestnut 
Wood Quail (Odontophorus hyperythrus, 275 g) 
in the Colombian Andes was 5.2 ha (Franco et al. 
2006) and home range of the Chowchilla 
(Orthonyx spaldingii . 150 g) in the Australian 
Wet Tropics was <2 ha (Jansen 1999). In 
contrast, the Banded Ground Cuckoo {Neomor- 
phus radiolosus , 433 g) we tracked for a similar 
time period in Bilsa had a home range of —50 ha 
(Karubian and Carrasco 2008). Movements of the 
radio-marked Brown Wood Rail suggest a clearly 
demarcated territory, and regular observations of 
footprints in the established core home range of 
this individual after the completion of radio¬ 
tracking suggest year-round residency. 
Brown Wood Rails in our study area appeared 
to exhibit a preference for secondary and 
selectively-logged forests. The entire home range 
of the radio-marked individual was restricted to 
secondary and selectively-logged forest, and a 
disproportionately high number of nests (15 of 16) 
we discovered were in secondary or selectively- 
logged forest. In contrast, the Banded Ground 
Cuckoo we tracked in the same general area of 
Bilsa restricted nesting and movements almost 
exclusively to primary forest (Karubian et al. 
2007, Karubian and Carrasco 2008). Some 
A)amides species have been reported in drier 
habitats such as deciduous woodlands (Taylor 
1996; R. S. Ridgely, pers. comm.), but the Brown 
Wood Rail may depend upon year-round avail¬ 
ability of water: the study area was humid 
per year (J. Karubian, unpubl. data). All foraging 
observations were of tadpoles in standing puddles 
or along creeks, and the individual we tracked was 
often in close proximity to water or muddy areas. 
Brown Wood Rails are cryptic, difficult to 
observe, unlikely to be captured by passive mist 
netting, and do not reliably respond to playback 
making censuses using traditional methods unre¬ 
liable. Local population size can be estimated 
with home range data with the caveat these data 
are only from a lone individual tracked for 
7 months. Assuming that Bilsa contains 1,500 ha of 
suitable habitat (e.g., secondary and selectively- 
logged forest; Jatun Sacha Foundation, unpubl. 
data) and that the species forms socially monoga¬ 
mous pairs with territories 10-15 ha in size, Bilsa 
could possibly support 100-150 pairs. Interviews 
with local residents and our own observations 
suggest this species is relatively common when 
suitable forest occurs outside the boundaries of 
Bilsa. We observed four old nests (not included 
in the analyses) and footprints in fragments of 
secondary forest and cacao plantations outside 
Bilsa (but <500 m from continuous forest). Our 
preliminary conclusion is that population size of 
this species in the 70,000-ha Mache-Chindul 
Reserve may be several hundred pairs. 
Bilsa and surrounding areas where Brown Wood 
Rail presence was inferred or confirmed consist of a 
mosaic of habitat types in which secondary forests 
are often contiguous to primaiy forest. Brown 
Wood Rails may persist in and even prefer 
secondary forests, but more extensive land clearing 
that increases isolation of forest fragments is likely 
to adversely affect this species. Our findings 
suggest Brown Wood Rails may be relatively 
resilient to intermediate levels of habitat degrada¬ 
tion encountered in our study area, but we consider 
its’ current status as ‘Vulnerable to Extinction' to be 
justified given the continued and widespread 
deforestation occurring throughout its range. 
ACKNOWLEDGMENTS 
We thank the staff of Bilsa Biological Station and 
Fundacion Jatun Sacha for support, especially Carlos 
Aulestia and Juliet Birmingham. We also extend special 
thanks to T. B. Smith for support. This article was improved 
by comments by C. E. Braun, R. S. Ridgely, and an 
anonymous reviewer. All research was conducted with 
permission from Fundacion Jatun Sacha and approval from 
the Ecuadorian Ministry of the Environment (Permit 
Number 009-CI-FAU-DRE-MA) and the University of 
California, Los Angeles Institutional Animal Care and Use 
