.--On 26 July 1990 (11:45 EST) at Reserva Natural Las Chinchillas (north-central Chile, 31 30'S, 7 l06'W) I observed a Great Shrike-Tyrant (Agriornis livida) capture a Green-backed Firecrown (Sephanoides sephanoides, Trochilidae) at a mistletoe patch (Tristerix aphylus). After dropping to the ground, the Great Shrike-Tyrant slammed the hummingbird against the ground with side- ways jerking motions. It then flew away with the hummingbird's limp body in its bill. Great Shrike-Tyrants are robust birds (about 100 g, Humphrey et al. 1970) with large, powerful, hooked bills. They are solitary and secretive but fairly common in the Mediterranean semiarid thorn-scrub vegetation of north-central Chile (Philippi 1964). Darwin states that he "was assured by the inhabitants that it is a very fierce bird and that it will attack and kill the young of other birds" (in Crashway 1907, p. 70). At Las Chinchillas, Great Shrike- Tyrants prey on lizards and large insects (J. E. Jim6nez, unpubl. data). My observation indicates that they are also capable of preying on hummingbirds. Stiles (1978) has suggested that Tiny Hawks (Accipiter superciliosus) catch hummingbirds by waiting quietly ("still- hunting") near territorial perches and flower clumps. My observation suggests that "still- hunting" near flower clumps may also be used by Great Shrike-Tyrants to catch hum- mingbirds. The rarity of predation observations on North American hummingbirds has prompted Miller and Gass (1985) to conclude that predation is not a significant risk for hummingbirds in temperate habitats and that biologists are justified in ignoring predation as a factor influencing hummingbird feeding behavior (see Lima 1991 for a contrasting view). In tropical habitats, predation by Bat Falcons (Falco rufigularis, Beebe 1950) and Tiny Hawks (Stiles 1978) may not justify this assumption. Jim6nez and Jaksic (1989) report remains of S. sephanoides, the most abundant Chilean hummingbird, in pellets of Austral Pigmy-Owls (Glaucidiurn nanurn) at Reserva Natural las Chinchillas. Only further observations will establish if predation by Great Shrike-Tyrants and Austral Pigmy-Owls represents a signif- icant risk to foraging hummingbirds in Chilean semiarid habitats. Acknowledgrnents.--J. Jim6nez provided housing and a wealth of information on the Natural History of Auc0. P. Feinsinger and J. Simonetti made my visit to Chile possible. M. Kinnard and T. O'Brien commented on the manuscript. LITERATURE CITED BEEBE, W. 1950. Hmelife ftheBatFalcn'Falc albigularisalbigularisDaudin'Z lgi- ca 35:69-86. CP, Asuw^, R. 1907. The birds ofTierra del Fuego. Bernard Quaritch, London, England. HUMPHREY, P.S., D. BmDGE, P. W. REYNOLDS, AND R. T. PETERSON. 1970. Preliminary Smithsonian manual for the birds of Isla Grande (Tierra del Fuego). Smithsonian Inst;tmion, Washington, D.C. JIIVINEZ, J. E. AND F. M. JAKSIC. 1989. Biology of the Austral Pigmy-Owl. Wilson Bull. 101:377-389. LIMA, S. L. 1991. Energy, predators and the behavior of feeding hummingbirds. Evol. Ecology 5:220-230. MILLER, R. S. AND C. L. GASS. 1985. Survivorship in hummingbirds: is predation im- portant? Auk 102:175-178. PHILIPPI, B. R.A. 1964. Catfilogo de las aves Chilenas con su distribuci6n geogrfifica. Investigaciones Zoo10gicas Chilenas 11:1-179. SHORT COMMUNICATIONS 369 STILES, F.G. 1978. Possible specialization for hummingbird-hunting in the Tiny Hawk. Auk 95:550-553. CARLOS MARTINEZ DEL RO, Dept. of Ecology and Evolutionary Biology, Princeton Univ., Princeton, New Jersey 08544-1003. Received 30 July 1991, accepted 24 Oct. 1991.