SHORT COMMUNICATIONS 
811 
Time of day 
FIG. 2. Nesl and ambient temperature patterns from a single nest of the Pectoral Sparrow during a 24-hr period. 
The overall average (± SD) nest temperature 
was27.9 ± 1,86° C (n = 28 days) and average nest 
temperature was 29.2 ± 2.64 C (n = 28 days) 
during incubation periods. Nest temperature de¬ 
creased to an average of 26.6 ± 2.43 C (n - 
28 days) during incubation recess. Overall average 
egg temperature was 32.0 C (range = 20.1-37.6. 
'i =12 days); and 34.8 C (range = 27.7—36.0 C. 
" = 12 days) when the female was on the nest; egg 
temperature decreased to 24.0 C (range = 18.4- 
&1 C, n =12 days) during foraging trips. 
DISCUSSION 
Ours is the first study comparing behavioral 
differences within Arrenwn. It is of interest that 
0esl architecture for two of the new species 
^cently added to the genus. A. brunneinucho and 
A lorquatus (Cadena et al. 2007) differ greatly 
trom other congeners. These two species nest in 
°P“n cups in the foliage (Skutch 1954. Skutch and 
Stiles 1989), while the remaining species with 
known nests construct closed domes al ground 
,ev 'el (Snethlage 1935. Skutch 1954, Havcr- 
'chmidt 1968. Tye and Tye 1992, Auer et al. 
2007). 
All nests of Pectoral Sparrow were domed 
Nl ructures, similar to those described for other 
members of the genus (Skutch 1954, Haver- 
sc hmidt 1968, Tye and Tyc 1992, Auer et al. 
2007). They were in predictable places (slopes 
next to creeks). Egg coloration was variable 
among females and incubation was solely by the 
female, which spent on average 61% of the 
daylight incubating and conducted on average 7.4 
trips per day each lasting on average 46.4 min. 
The male supplied most of the food, although both 
parents provisioned the nestlings. 
Nest and Eggs.— Dome nesting species within 
Arremon had similar nest locations and materials; 
average nest height for A. flavirostris and A. 
tacitunnis was 0.0 m (range = 0.0-0.9 m, n = 54) 
and 0.1 m (range = 0.0-1.0 m, n = 15), 
respectively (Auer et al. 2007). In contrast, cup- 
nesting species, A. bnumeinucha and A. torqua- 
lus, place their ne.sts in vine tangles or bamboo 
between 1.2 and 8.3 m above ground with two 
nests recorded >20 m above ground (Skutch 
1954, Skutch and Stiles 1989, Auer el al. 2007). 
Nest material also differed between cup- and 
dome-nesting species. Both have an external layer 
composed mostly of dead leaves and an inner 
lining of rootlets, but none of the cup-nesting 
species was reported to use green material, while 
all ground-nesting species have been reported to 
use green materials (moss, ferns, leaves or 
grasses) in the outer layer (Skutch 1954, Schulen- 
berg and Gill 1987. Tye and Tye 1992). The use 
of green materials in nests of A. aurantiirostris 
and A. castaneiceps , as in A. tacitunnis, appears to 
function to blend the nest with the surrounding 
