The Wilson Journal of Ornithology 124(3):531-537. 2012 
BREEDING BIOLOGY OF THE SOUTHERN HOUSE WREN ON CHILOE 
ISLAND, SOUTHERN CHILE 
SILVINA IPPL' 3 5 RODRIGO A. VASQUEZ.' JUAN MORENO. * 2 * 
SANTIAGO MERINO. 2 AND CAM1LA P. VILLAVICENCIO 14 
ABSTRACT.—We studied the breeding biology of a Southern House Wren ( Troglodytes aedon chilensis) population 
using nest boxes on Chiloe Island, southern Chile (41 S) to make latitudinal comparisons at the intraspecific level. There 
were no significant differences in body size between adult males and females, although wings were significantly longer in 
make Clutch size averaged 4.3 eggs per nest, and brood size was 3.9 nestlings. Egg size averaged 1 7.3 mm in length and 
13.2 nun in width. Incubation and nestling periods averaged 16 days each. The Southern House Wren on Chiloe Island has a 
larger clutch size than in the tropics, hut a smaller clutch size than populations at the same latitude in the Northern 
Hemisphere. The Southern House Wren has larger eggs and a longer incubation period but a similar nestling period as 
House Wrens in the Northern Hemisphere Received 23 August 2011. Accepted 29 January 2012. 
Studies of species with a broad distributional 
range are valuable to gain information on the 
latitudinal effects on physiology and morphology 
as well as behavior and life history traits. Know¬ 
ledge of breeding biology is useful for testing 
hypotheses about effects of latitude on clutch size, 
parental care, and breeding phenology (Geffen 
and Yom-Tov 2000). However, in comparison 
with Northern Hemisphere species, few studies 
have been conducted on the breeding biology of 
South American species, where information about 
natural history of numerous species is lacking 
(Geffen and Yom-Tov 2000. Russell et al. 2004). 
The House Wren (Troglodytes aedon: Tt'Oglo- 
dytidae) has a distribution from southern Canada 
to southern Chile, encompassing one of the largest 
latitudinal distributions for any native passerine 
species (Johnson 1998). Brumfield and Caparella 
r 1996) recommended re-elevating the three main 
recognized taxonomic groups to species level: T. 
aedon (Northern House Wren), T bnmneicollis 
i Brown-throated House Wren), and T. muse it his 
•Southern House Wren). The House Wren is cur¬ 
rently considered a single species (Johnson 1998. 
Bird Life International 2011, Gill and Donsker 
-912) and we use the common name Southern 
Insiiiutode Ecologia y BiodiveiNidacl. Dcpartamento de 
Gencias Ecoldgicas. l niversiclad dc Chile. La<> Palmcras 
*425. Xuftoa, Santiago. Chile. 
: Departanienlo de Ecologia Evolutiva. Museo Nacional 
& Ciencias Naturales-CSIC. E-2SfH)6. Madrid. Spain. 
Current address: lastinito de Ecologia v Biodivcrsidad. 
hepartamento de Ecologia. Pontificia Tniversidad Catblica 
de Chile. Alameda 340. 6513677. Santiago. Chile. 
4 Current address: Max Planck Institute for Ornithology. 
Department ot Behavioural Neurobiology. Eberhard-Gwin- 
ner-Strasse. House 6a. D-82319. Seewiesen. Germany. 
Corresponding author; e-mail: silvippi@yahoo.com 
House Wren for the subspecies 7'. a. chilensis in 
our study. 
The Southern House Wren inhabits the austral 
extreme of Chile and Argentina. It is a small 
insectivorous bird and a secondary cavity nester 
(Johnson and Goodall 1967. Grigera 1982, 
Kroodsma and Brewer 2005). It typically inhabits 
scrublands and secondary or marginal forests on 
the island of Chilot 4 (41 S) (Rozzi et al. 1996. 
Diaz et al. 2005) and is also common in urban 
areas (Diaz and Armesto 2003): it is similar to 
populations of the Northern Hemisphere House 
Wren (Johnson 1998). The Southern House Wren 
is considered a year-round resident on Chiloe 
Island (Jaramillo et al. 2003). but detection during 
autumn and winter is difficult, suggesting partial 
migration (S. fppi. unpub. data). The House Wien 
is an ideal species model, because of its extensive 
geographic range, for assessing the ellects ol lati¬ 
tude on intraspecific variation of breeding biology 
(e.g., Young 1994). Comparisons of life-history 
traits with the Northern House Wren, would be 
informative due to the large amount oi informa- 
tion available about the ecology and breeding 
biology of the species in the Northern Hemi¬ 
sphere (e.g.. Kendeigh 1941; Kendeigh et al. 1956: 
Drilling and Thompson 1988: Johnson and Searcy 
1993. 1996; Johnson 1996; Johnson et al. 2001; 
Janota et al. 2002; Johnson et al. 2008. 2009). 
Several ecological and reproductive studies have 
recently been conducted in South America, mainly 
in Argentina (e.g.. Tuero et al. 2007. Fasanella and 
Fernandez 2009. Llambfas and Fernandez 2009. 
Labarbera et al. 2010. Serra and Fernandez 2011). 
The objective of our study was to describe the 
breeding biology of the Southern House Wren in a 
southern Chilean population and to compare our 
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