Table Of Content508 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 119, No. 3, September2007
prised that we encountered relatively few LITERATURE CITED
thrushes on or near the ground, despite the Bakken, L. E. and G. S. Bakken. 1977. American
number and diversity of flight-calls from Redstart feeding by artificial light. Auk 94:373-
thrushes passing overhead. We are unable to 374.
explain why few thrushes landed during this Bird, B. L., L. C. Branch, and D. L. Miller. 2004.
event while so many warblers and other spe- Effects ofcoastal lighting on foragingbehaviorof
beach mice. Conservation Biology 18:1435-1339.
cies were grounded. Dinsmore, S. J. and a. E Farnsworth. 2006. The
changing seasons: weatherbirds. North American
ACKNOWLEDGMENTS
Birds 60:14-26.
Latham, R. 1936. Catbirds and moths. Oologist 53:
We thank numerous observers including J. R. Bar- 69-72.
nett, R. N. Douglas, S. A. Haber, T. B. Johnson, C. A. Le Corre, M., M. Ollivier, S. Ribes, and P. Jouven-
Marantz, L. G. Samsonenko, G. F. Seeholzer, B. L. TiN. 2002. Light-induced mortality ofpetrels: a4-
Sullivan, C. W. Thoreen, and E. R. Wallace. Patrick year study from Reunion Island (Indian Ocean).
Graham provided light bulb specifications. Robert Biological Conservation 105:93-102.
DeCandido, Andrew Farnsworth, and an anonymous Rich, C. and T. Longcore (Editors). 2006. Ecological
reviewer provided useful comments on this manu- consequences of artificial night lighting. Island
script. Press, Washington, D.C., USA.
The Wilson Journal ofOrnithology 119(3):508-510, 2007
Yellow-throated and Red-eyed Vireos Foraging on Green Anoles
During Migration
Paul W. Sykes Lyn S. Atherton,^ and Rebecca L. Payne^
—
ABSTRACT. Yellow-throated (Vireo fiavifrons) Ridgely and Tudor 1989, Rodewald andJames
and Red-eyed vireos (V. olivaceus) were observed 1996, Cimprich et al. 2000). The diet of the
feeding on green anoles {Anolis carolinensis caroli- Yellow-throated Vireo (Vireo fiavifrons),
nensis) at two localities in Florida and one in South
based upon analysis of 160 stomachs from
Carolina. Vireos are long-distance migrants that re-
quire foods high in fatty acid content, especially when specimens collected from April through Sep-
engaging in migration. It is not unlikely that vireos tember in breeding areas throughout North
have an opportunistic foraging strategy to obtain the America, consists of98.3% animal matter and
necessary food requirements, including attacking and 1.7% plant material (including small fruits and
consuming prey items such as small lizards. This note seeds). Insects (Insecta; eggs, instars, and
provides the first published reports of lizards taken as
prey by these two species. Received 24 November adults of at least five Orders) comprise 95.8%
2006. Accepted 20 March 2007. of the animal food with the remainder being
spiders (Arachnida) 2.4% and small snails
(Mollusca) 0.06% (Chapin 1925). Butterflies
The diets of North American vireos have and moths (Lepidoptera) accounted for42%+
been well described (Chapin 1925, Tyler of the insects taken and vegetable matter was
1950, Williamson 1971, Graber et al. 1985, primarily consumed in fall and winter (Chapin
1925, Rodewald and James 1996). The diet of
' USGS, Patuxent Wildlife ResearchCenter,Warnell the Red-eyed Vireo (Vireo olivaceus) has been
School of Forestry and Natural Resources, University summarized by Chapin (1925), Tyler (1950),
ofGeorgia, Athens, GA 30602, USA. and more recently by Cimprich et al. (2000).
2 1100Pinellas Bayway 1-3,TierraVerde,FL33715, Food items consist of insects (Insecta; eggs,
USA.
-M716 Shorecrest Dr., Orlando, FL 32817, USA. instars, and adults of at least eight Orders),
Corresponding author; e-mail: spiders (Arachnida), small snails (Mollusca),
[email protected] a large variety of small fruits, and occasion-
SHORT COMMUNICATIONS 509
ally flowers and leafbuds (Chapin 1925, Cim- hrs EDT at Key West, Monroe County, Flor-
prich et al. 2000). Contents of 569 stomachs ida on 13 April 1987. The vireo, perched in a
(Apr-Oct) within the breeding range included strangler fig {Ficus aiirea), was observed
85% animal matter and 15% plant material feeding on the lizard for 35 min. It first pulled
(Chapin 1925). Small fruits were most fre- pieces of flesh from the head, eating the eyes
quently taken in late summer and fall in and what appeared to be the brain. After tear-
breeding areas (Chapin 1925, Tyler 1950, Wil- ing the remains ofthe head from the body and
liamson 1971, Graberet al. 1985). The species dropping the head to the ground, the bird fed
is almost entirely frugivorous while wintering on the tissue of the neck region. The vireo bit
in northern South America (Ridgely and Tu- offthe legs and tail, and discarded them while
dor 1989). feeding on the anole’s abdomen. LSA later
Vireos kill larger prey by crushing, shaking watched a migrant Red-eyed Vireo for5+ min
m
vigorously, or beating against a branch at 7 eating a green anole at Ft. DeSoto
(Southern 1958, Rodewald and James 1996). County Park (Mullet Key), Pinellas County,
Smaller prey is swallowed whole. Larger prey Florida in mid morning on 27 April 1987. The
are held with a foot against a branch and eaten bird was perched 3 m above ground in a wom-
piecemeal (Williamson 1971, Rodewald and an’s tongue tree {Albizici lebbeck).
James 1996). The objective of our paper is to
DISCUSSION
report two species ofvireos feeding onAnolis
lizards during migration in South Carolina and These appear to be the first reports of Yel-
Florida, USA. low-throated and Red-eyed vireos feeding on
lizards; literature searches did not reveal rep-
OBSERVATIONS
tiles or amphibians having been reported tak-
On 21 September 2006, while searching for en by these two species. There is a record of
neotropical migrants in the maritime forest at a White-eyed Vireo {Vireo griseus) feeding on
Myrtle Beach State Park, Horry County, a small Anolis (Chapin 1925, Hopp et al.
South Carolina, PWS observed an adult Red- 1995). This appears to be the only previously
eyed Vireo feeding on a brown-colored green published account of a vireo feeding on a liz-
anole {Anolis carolinensis carolinensis). This ard. Prior to the 1987 observations, the late
abundant small arboreal lizard has: (1) the Larry Hopkins (pers. comm., with LSA) re-
ability to change color (green to brown and ported watching a migrant Yellow-throated
vice versa), (2) a wide range in the south- Vireo feeding on an introduced Cuban brown
eastern United States, and (3) attains a length anole {Anolis scigrei sagrei) (Conant 1958) at
up to 19 cm, 60-65% of this length being the Ft. DeSoto County Park, Pinellas County,
tail (Conant 1958). The bird had apparently Florida. All three vireos are long-distance mi-
just captured the anole, ~ 12-13 cm in length grants that possess the ability to greatly in-
and still limp, but the event was not wit- crease fat stores in preparation for migration
nessed. The bird held the lizard with its left (i.e., become hyperphagic), especially before
foot against a branch and was steadily pecking a trans-Gulf flight (Moore et al. 1995). The
the head, removing and swallowing small energetic costs of migration require high lev-
pieces of tissue. PWS watched this procedure els offatty acid in the diet ofRed-eyed Vireos
for 15+ min with binoculars at an estimated (Pierce and McWilliams 2005). Moreover, nu-
m
6 with the bird clearly illuminated in direct merous nutritional requirements of individual
sunlight. The bird was perched in a sweetgum vireos during the breeding season (Pierce et
(Liquidambar styraciflua) at a height of 5 m. al. 2004, Pierce and McWilliams 2005) likely
The body and head of the anole were still in- result in these species exhibiting opportunistic
tact, further indicating recent capture. When foraging behavior. Vireos are almost com-
the vireo changed position on the branch, it pletely insectivorous requiring at least 75-
continued to hold the anole with its left foot. 85% animal matter in their diets (Cimprich et
When PWS left the site, the vireo was still al. 2000, Pierce and McWilliams 2005). Red-
actively feeding on the anole. eyed Vireos in laboratory tests routinely chose
LSA and RLP observed a migrant Yellow- diets with higher fatty acid content (Cimprich
throated Vireo eating a green anole at 0900 et al. 2000, Pierce et al. 2004). Thus, it is like-
510 THE WILSON JOURNAL OL ORNITHOLOGY • Vol. 119, No. 3, September 2007
ly that vireos will attack and consume numer- 2000. Red-eyed Vireo{Vireoolivaceus).Thebirds
ous animal species, including small lizards, ofNorth America. Number 527.
when the opportunity arises. Conant, R. 1958. The Peterson field guide series. A
Two of the vireos we observed (Apr) were efidelSdtgauteisdeantodrCepatnialedsaaenadstamopfhithbeia1n0s0“o^fmtehreidUinaint.-
in migration. One vireo observed (Sep), was Houghton Mifflin Company, Boston, Massachu-
likely preparing for migration to wintering ar- setts, USA.
eas in South America. It is likely the three Graber, J. W, R. R. Graber, and E. L. Kirk. 1985.
birds were in an energetic state that required Illinois birds: vireos. Biological Notes, Number
a highly nutritious food resource. Vireos are 68. IllinoisNatural History Survey, Urbana,USA.
known to be opportunistic foragers during mi- Hopp,eySe.dL.V,iAr.eoKi{rVbiyr,eoangdrisCe.usA)..BTohoeneb.ir1d9s95o.fWhNiotret-h
gration (Woodrey and Moore 1997). It is pos- America. Number 168.
sible that at least the two species of vireos we Moore, E R., S. A. Gauthreaux Jr., P. Kerlinger,
observed take small lizards as prey with great- ANDT. R. Simons. 1995. Habitatrequirementsdur-
er frequency than current evidence indicates. ing migration: important link in conservation.
We did not observe captures of the lizards by Pages 121-144 in Ecology and management of
the vireos and do not know the specifics as to Mne.otErionpcihc,alEdmiitgorrsa)t.orOyxfboirrddsUn(Ti.veEr.siMtayrtPirenssa,nNdeDw.
how vireos actually obtained these prey, the York. USA.
physical condition of the prey at time of cap- Pierce, B. J. and S. R. McWilliams. 2005. Seasonal
ture, or other circumstances involved. changes in composition of lipid stores in migra-
Recent accounts ofother small insect-eating tory birds: causes and consequences. Condor 107:
birds taking small vertebrate prey include: (1) 269-279.
a migrant SummerTanager {Piranga ruhra) at Pierce, B. J., S. R. McWilliams, A. R. Place, andM.
A. Huguenin. 2004. Diet preferences for specific
Horn Island off the coast of Mississippi on 3 fatty acids and their effect on composition of fat
April 1993 eating a green anole (Aborn and reserves in migratory Red-eyed Vireos {Vireo ol-
Froehlich 1995), and (2) a House Wren {Trog- ivaceous). Comparative Biochemical Physiology
lodytes aedon) eating a juvenile house gecko 138:503-514.
(Hemidactylusfrenatus) in Golfito, Costa Rica Ridgely, R. S. and G. Tudor. 1989. The Birds of
on 22 May 2002 (Barquero and Hilje 2005). South America. Volume 1. The oscine passerines.
University ofTexas Press, Austin, USA.
ACKNOWLEDGMENTS Rodewald, P. G. and R. D. James. 1996. Yellow-
throated Vireo {Vireo flavifrons). The birds of
We thank Bonnie and Cam Kepler, and Lynda Gar- North America. Number 247.
rett for assistance. The note was greatly enhanced by Southern, W. E. 1958. Nesting ofthe Red-eyed Vireo
reviews of M. R Guilfoyle, S. L. Hopp, and C. E. in Douglas Lake region, Michigan. Jack-Pine
Braun. Warbler 36:105-130,185-207.
LITERATURE CITED Tyler, W. M. 1950. Vireo olivaceus (Linnaeus) Red-
eyed Vireo. Pages 335—348 in Life histories of
Aborn, D. A. and D. Lroehuch. 1995. An observa- North American wagtails, shrikes, vireos, and
tion of a Summer Tanager attempting to eat an theirallies(A.C. Bent, Editor). U.S. NationalMu-
Anoli.s lizard. Journal of Lield Ornithology 66: seum Bulletin 197.
501-502. Williamson, P. 1971. EeedingecologyoftheRed-eyed
Barquero, M. D. and B. Hilje. 2005. House Wren Vireo {Vireo olivaceus) and associated foliage-
preys on introduced gecko in Costa Rica. Wilson gleaning birds. Ecological Monographs 41:129-
Bulletin 117:204-205. 152.
Chapin, E. A. 1925. Lood habitsofthe vireos: afamily Woodrey, M. S. and E R. Moore. 1997. Age-related
of insectivorous birds. U.S. Department of Agri- timing differences in stopoveroffall landbird mi-
culture Bulletin 1355. grants on the coast of Alabama. Auk 114:695—
CiMPRicH, D. A., L R. Moore, and M. P. Guilfoyle. 707.
