416 
THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 
Meents, J. K. 1979. Avian community structure in 
Chihuahuan desert grasslands. Dissertation. New 
Mexico State University, Las Cruces, USA. 
Ripley. S. D. 1949. Texas habitat of Botteri’s Sparrow and 
Gulf Coast records of wintering sparrows. Wilson 
Bulletin 61:112-113. 
Webb, E. A. 1985. Distribution, habitat and breeding biology 
of the Botteri's Sparrow (Aimophila botterii arizonae). 
Thesis. University of Colorado, Boulder. USA. 
Webb, E. A. and C. E. Bock. 1996. Botteri's Sparrow 
(Aimophila botterii). The birds of North America. 
Number 216. 
Webster. J. D. 1959. A revision of the Botteri Sparrow 
Condor 61:136-146. 
The Wilson Journal of Ornithology 123(2):416—417. 2011 
The Orange-breasted Thornbird (Phacellodomus ferrugineigula) (Furnariidae): 
A New Effective Host of Shiny Cowbird (Molothrus bonariensis) (Icteridae) 
Giovanni Nachtigall Maurfcio' 
ABSTRACT.—Over 250 bird species have been 
listed as victims of the Shiny Cowbird (Molothrus 
bonariensis). a well-known obligate brood parasite. 
Five of the nine species of Phacellodomus (thombirds) 
have been listed as victims, but none has been reported 
rearing cowbird fledglings. I report observations of a 
pair of Orange-breasted Thombirds (Phacellodomus 
ferrugineigula) rearing two fledgling Shiny Cowbirds in 
southern Brazil. These data add a new host for the Shiny 
Cowbird and constitute the first report of a species of 
the genus Phacellodomus as an effective host of cow- 
birds. Received 5 January 2011. Accepted 30 March 
2011 . 
The Shiny Cowbird (Molothrus bonariensis) is 
a well-known generalist, obligate brood parasite 
occurring from southern Argentina to the southern 
USA (Lowther and Post 1999). The list of birds 
parasitized by this icterid has increased signifi¬ 
cantly since the early compilation by Friedmann 
(1929). Whereas Friedmann (1929) found 98 
species and subspecies parasitized by the Shiny 
Cowbird, Lowther and Post (1999) listed 232 
species as parasitized while that total reached 251 
in the most recent and updated compilation 
(Lowther 2010). Five of the nine species of the 
fumariid genus Phacellodomus (thombirds) have 
been reported as being parasitized by the Shiny 
Cowbird (Lowther 2010). Among the remaining 
four species is the Orange-breasted Thornbird (P. 
ferrugineigula ), an Atlantic Forest endemic re¬ 
cently split from the Orange-eyed Thornbird ( P. 
‘Grupo Especial dc Estudo e Prote^ao do Ambiente 
Aqudtico do Rio Grande do Sul (GEEPAA-RS), Ruu 
Tiradentes, 2247, Pclotas, Rio Grande do Sul, Brazil; e-mail: 
gnachtigall mauricio @ yahoo.com .br 
erythrophthalmus ) (Simon et al. 2008). J present 
the first record of parasitism of the Orange¬ 
breasted Thornbird by the Shiny Cowbird. docu¬ 
menting it as an effective host of the cowbird. 
OBSERVATIONS 
Data on interactions between the Shiny Cow¬ 
bird and Orange-breasted Thornbird were gath¬ 
ered at the edge of a large peat marsh at the beach 
town of I.aranjal (31 46' S, 52 14' W, sea level), 
municipality of Pelotas, Rio Grande do Sul, 
Brazil. These observations were made on a daily 
basis between 2 and 21 December 1997. resulting 
in 30 hrs of field work (30 min to 5 hrs per day). 
I discovered a pair of out-of-nest Shiny 
Cowbirds on 2 December 1997 soliciting food 
from a pair of Orange-breasted Thombirds on the 
edge of the dense vegetation of the marsh 
bordering the urbanized area of the town. The 
parasites were in brown (1) and blackish ill 
plumage, the latter matching the description of the 
melanagyna female morph (Fraga in press). On 
average (± SD), they were fed by their hosts 10,2 
(± 3.2) times/hr (range = 8-15). considering only 
periods of continuous observations of the parasites 
(n = 4 hrs). All food items observed in detail (n - 
26) were insects, of which most were small 
(smaller than or as large as the thombird's bill', 
but at least six were caterpillars larger than bill 
size and five were dragonflies. The parasitic pair 
generally followed the hosts very closely, solic¬ 
iting food on most occasions when the thombirds 
emerged from the dense marsh vegetation ' v b ere 
they routinely foraged. The thombirds also 
followed the cowbirds to feed them, in several 
cases climbing to considerable heights (e.g.. 4 m 
