SHORT COMMUNICATIONS 
813 
tubular, elongated, and messy, composed of dead 
plant fibers, some green fern-like material, and at 
least one piece of blue plastic ribbon. We 
observed a male and female Thick-billed Eu- 
phonia both remove nest material from Nest A 
and fly off with the material while the Red-faced 
Spinetails were out of view. 
We observed two Red-faced Spinetails near 
Nest A during the morning of 2 February 2011 
and saw at least one of the birds enter the nest. We 
also discovered an active Golden-laced lyrannu- 
let nest within 30 m of Nest A. 
We discovered a second Red-faced Spinetail 
nest thereafter Nest B) on 20 February 2011 at 
0945 hrs COT in the same tree as Nest A and began 
a 30-min observation. Nest B was approximately 
the same height as Nest A. but was 2 m distant in a 
different fork of the same downward-hanging 
branch. Nest B was more spherical than Nest A 
with an obvious side entrance and long pieces ot 
material hanging from the nest. We saw' a Red- 
faced Spinetail remove material from Nest A 
during the 30-min observation and fly trom sight 
with the material. A Red-faced Spinetail was seen 
returning from the same direction less than I min 
later to Nest B with nesting material. We later 
observed a Red-faced Spinetail remove material 
from Nest A and bring it directly to Nest B. 
We returned to the nest site on 20 February 2011 
at 1123 hrs and conducted a 24-min observation 
during which we did not detect any Red-laced 
Spinetails. We observed a Golden-faccd 1 yrannu- 
let perch on or enter Nest B at 1133 hrs ami leave 
without any material visible in its bill. 
We visited the nest site again on 22 February 
2011 at 1027 hrs and conducted a 167-min 
observation. We observed at least two Red-laced 
•Spinetails between 1027 and 1124 hrs make lour 
visits to Nest A and three visits to Nest B. The 
Red-faced Spinetails adjusted the position ol nest 
material in both Nest A and Nest B. but we did not 
definitively see birds arriving or departing with 
nesting material. We observed a Golden-faced 
Tyrannulet at 1153 hrs fly 10 Nest B, remove 
nesting material with its bill, and depart with the 
material. We observed a Red-faced Spinetail at 
1221 hrs 11 y to Nest A without material, remove a 
piece of material from Nest A. bring that material 
to Nest B. reposition some material in Nest B. and 
periodically vocalize from inside Nest B until 
leaving the nest at 1229 hrs. A Red-laced 
Spinetail silently entered Nest B at 1244 hrs. 
repositioned nesting material, and left at an 
unknown time. We observed a Red-faced Spine¬ 
tail at 1248 hrs foraging and vocalizing within 
30 m of the nest lice. The bird pulled epiphytic 
plant material from a tree trunk, brought it to Nest 
B. and left at 1250 hrs after repositioning the 
material in the nest. A Red-faced Spinetail entered 
Nest B at 1251 hrs and repositioned material 
inside the nest until leaving the nest at 1257 hrs. 
DISCUSSION 
Reports of nest material kleptopurasitism in 
non-colonial birds arc unevenly distributed across 
geographic and phylogenetic space. The behavior 
has been reported in the Eastern Hemisphere and 
Hawaiian Islands in Meliphagidue, Pardalotidae, 
Acanthizidae, Remizidac. Zosteropidae, Dicaei- 
dae Fringillidae. and Remizidac (Ashton 1987, 
Schleicher et al. 1993, Ley cl al. 1997. Vander- 
Werf 1998). There are reports of nest material 
kleptoparasitism in North America in Vireonidae. 
Polioptilidae. Parulidae. and Icteridae (Jones et al. 
2007). Relatively few studies report nest material 
kleptoparasitism in neotropical birds despite the 
region's high avian diversity: reports of the 
behavior are available from Trochilidae (Skutch 
1931, Haverschmidt 1952; F. G. Stiles, pers. 
comm.), Furnariidae tRcmsen 2003), Tyrannidae 
(Smith 1980; F. G. Stiles, pers. comm.), and 
Fringillidae (F. G. Stiles, pers. comm.). The 
scarcity of literature on nest material kleptopai- 
asitism obscures whether such patterns aic 
sampling artifacts or true biological phenomena. 
Geographic trends in the prevalence of this 
behavior may arise from regional differences in 
habitat structure, resource availability, or com- 
munity-wide life histories, whereas phylogenetic 
trends could emerge due to evolutionary conser¬ 
vatism of nest-building behaviors. 
We observed Thick-billed Euphonias and a 
Golden-faced Tyrannulet klcptoparasitizing material 
from a Red-faced Spinetail nest site. These obser¬ 
vations to our knowledge represent the first account 
of nest material kleptoparasitism by the Golden¬ 
faced Tvrannulet (Goulding and Martin 2010). Nest 
material kleptoparasitism has been reported previ¬ 
ously in Fringillidae and Tyrannidae, and out 
observations are consistent with the possibility this 
behavior may be more frequent or widespread in 
these families than previously thought. 
Nest building is often costly for birds, and 
selection might favor construction strategies that 
minimize costs of nest building (Gauthier and 
Thomas 1993). Nest material kleptoparasitism may 
