812 
THE WrLSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 4. December 2012 
The Wilson Journal of Ornithology 124(4):812—815, 2012 
Kleptoparasitism of Nesting Material from a Red-faced Spinetail 
(Cranioleuca erythrops) Nest Site 
David L. Slager , 12 Molly E. McDermott , 1 and Amanda D. Rodewald' 
ABSTRACT.—We report observations of Thick¬ 
billed Enphonias (F.uphonia laniirostris) and a Gold 
en-loced Tyrannulet (Zimmerius chrysops) kleptopai - 
asiti/ing nesi material from Red-faced Spinetail (Cra- 
ni ole in a erythrops) nests in Antioquia, Colombia. 
Thick-billed Euphonias (12 -t 1 m. n -= I I encounters) 
and Golden-faced Tyiannulcts (10 ± | m . n = 19 ) at 
our study site typically foraged at similar heights as the 
Red-faced Spinetail nests they parasitized (9 in for both 
nests), consistent with the idea that a klcptoparusile 
might steal material from nests in its home stratum to 
avoid predation risk associated with descending to the 
ground in search of nest material. We encourage 
ornithologists to continue reporting instances of nest 
material kleptoparasitism so its prevalence in birds can 
be rigorously assessed. Received 21 March 2012. 
Accepted 18 June 2012. 
Nest material kleptoparasitism commonly oc¬ 
curs among colonially-nesting birds subject to 
intense competition for nest materials (Colliasand 
Collins 1984. Moreno cl al. 1995). Reports of nest 
material kleptoparasitism in solitary breeding 
species tire much less frequent. We describe 
observations ot Thick-billed Euphonias (Eupho- 
nia laniirostris) and a Golden-faced Tyrannulet 
(Zimrnetins chrysops) kleptoparasitizing nest ma¬ 
terial from a Red-faced Spinetail (Cranioleuca 
cryl/itops) nest site and discuss the potential 
significance of the behavior. 
METHODS 
Nest material kleptoparasitism has been reporl- 
ed for a variety of birds in scattered accounts, yet 
the ecological context of the behavior remains 
largely untested and speculative. Potential bene¬ 
fits ol nest material kleptoparasitism to the 
parasite may include: (I) reduced competition 
for a limited supply of nest materials, (2) easier 
access to certain rare materials that may otherwise 
be inaccessible to the kleptoparasite, (3) reduced 
locomotive energy expenditure during nest build¬ 
ing due to decreased time and distance to nest 
materials. (4) increased time available for nest 
guarding due to less time spent away from the 
nest, (5) reduced predation risk during nest 
material gathering in less familiar microhabitats, 
and (6) reduced risk of predators or brood 
parasites detecting the kleptoparasile’s nest due 
to fewer required visits or shorter flights (Ley 
et al. 1997, Jones et al. 2007). Possible costs of 
kleptoparasitic behavior to the parasite might 
mdude: (I) aggressive interactions from the host 
during nest defense, and (2) transmission of nest 
Parasites (Ley et al. 1997). 
'School of Environment and Natural Resources, Old, 
Stale University. 210 Kottmnn Hall. 2021 Coffev Ron 
Columbus, OH 432 10. I IS A. * 
2 Corresponding author; e-mail: slager.4@osu.edu 
We conducted observations at La Virgen de 
Oro shade coffee plantation on the east slope of 
the Western Cordillera of the Andes in the mu¬ 
nicipality ol Tame,sis. Department of Antioquia, 
Colombia (05 44 ' 56.8" N. 75 42' 06.5" W; 
1.500 m asl). We conducted 15 days of bird 
observations from 26 January to 3 February 2011 
and Irom 17 to 22 February 2011. systematically 
traversing the farm at —500 m/hr. W'e recorded 
foraging heights of individual birds upon encoun¬ 
tering mixed-species flocks. We estimated that 
one or two pairs ol Red-faced SpinetaiLs occupied 
the study site and that Thick-billed Euphonias 
were common and Golden-faced Tvrannulets 
were abundant. Nogal (Cordia altiodora) and 
guumo (Inga sp.) trees dominated the open and 
heterogeneous canopy in this agroforestry system. 
A midstory was generally lacking with the 
understory dominated by 2-m high coffee shrubs 
(Coffea arahica) and a <0.5-m high herbaceous 
layet. We measured foraging height. nest height, 
and tree height using a Nikon Forestry 550 
Hypsometer (Melville. NY, USA). 
OBSERVATIONS 
We discovered two Red-faced SpinetaiIs adding 
material to a nest (hereafter Nest A) on the 
morning of 30 January 2011. Nest A was 9 m high 
at the end ot a low hanging branch, 4 m from the 
main H unk ot a 15-m tree. The nest was somewhat 
