Table Of Content

128 THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 119, No. 1, March 2007 avian species not known for brood parasitic Brawn, J. D. 1990. Interspecific competition and so- behavior (Bailey 1886, Holcomb 1967, Wiens cial behavior in Violet-green Swallows. Auk 107: 1971, Gustafson 1975, Canned and Harring- 606-608. ton 1984, Littlefield 1984, Carter 1987, Sealy Brown, C. R., A. M. Knott,andE.J. Damrose. 1992. Violet-green Swallow (Tachycineta thalassina). 1989). Females may lay in another cavity be- The birds of North America. Number 14. cause they are unable to approach their own Cannell, R F. and B. a. Harrington. 1984. Interspe- cavity at the time of laying, due to the pres- cific egg dumping by a Great Egret and Black- ence of a predator, nest usurpation, or other crowned Night Herons. Auk 101:889-891. disturbance. Based on monitoring ofnest box- Carter, M. D. 1987. An incident ofbrood parasitism es at Hastings Reservation, 11.2% of 98 Vi- by the Verdin. Wilson Bulletin 99:136. olet-green Swallow nests with at least one egg Dickinson, J. L., W. D. Koenig, and F. A. Pitelka. failed before hatching from 1983 through 1996. Fitnessconsequencesofhelpingbehaviorin the Western Bluebird. Behavioral Ecology 7:168- 2005. This small incidence ofnest failure dur- 177. ing laying and incubation is only partially at- Eltzroth, E. K. and S. R. Robinson. 1984. Violet- tributable to predation, but indicates that in- green Swallows help Western Bluebirds at the frequent nest predation or disturbance during nest. Journal ofField Ornithology 55:259-261. laying could account for the behavior we ob- Guinan, j. a., P. a. Gowaty, and E. K. Eltzroth. served. Although there are no data on conspe- 2000. Western Bluebird (Sialia rnexicana). The cific nest usurpation in Violet-green Swal- birds of North America. Number 510. lows, nest usurpation has been well docu- Gustafson, J. R. 1975. A Sage Sparrow egg in a Black-throated Sparrow nest. Auk 92:805-806. mented in Tree Swallows (Tcichycineta bicol- Holcomb, L. C. 1967. Mourning Dove egg in nest of or) (Leffelaar 1985). catbird and robin. Wilson Bulletin 79:450-451. ACKNOWLEDGMENTS Leffelaar, D. and R. J. Robertson. 1985. Nest usur- We thank Wendy Fair and Caitlin Stern for helpful pation and female competition for breeding op- portunities by Tree Swallows. Wilson Bulletin 97: comments and Cachagua General Store forgastronom- ical support. This research was funded by NSF grant 221-224. lBN-009702toJLD. Editedvideofootagemaybeviewed Littlefield, C. D. 1984. Sandhill Crane incubates a Canada Goose egg. Wilson Bulletin 96:719. at: http://www.birds.comell.edu/birdhouse/nestboxcam/ movies_home/vgsw_in_webl courtesy of Cornell Labo- Sealy, S. G. 1989. Incidental “egg dumping” by the ratory of Ornithology’s “The Birdhouse Network.” House Wren in a Yellow Warbler nest. Wilson Bulletin 101:491-493. LITERATURE CITED Wiens, J. A. 1971. “Egg-dumping” by the Grasshop- Bailey, H. B. 1886. The Brown Thrush laying in the per Sparrow in a Savannah Sparrow nest. Auk 88: nest of the Wood Thrush. Auk 4:78. 185-186. The Wilson Journal ofOrnithology 1 19(1):128—129, 2007 Western Bluebird Captures a Western Fence Lizard Caitlin A. Stern'•“ — ABSTRACT. 1 observed a male Western Bluebird there is one previous report ofa Western Bluebirdcar- (Sialia nie.xicana) capture a western fence lizard rying an unidentified lizard in the manner of a prey loporus occidentalis). the first reported incidence of item, and a few reports ofpredation on vertebrates by vertebrate-directed raptorial behavior in the Western the congeneric Eastern Bluebird {Sialia sialis). Re- Bluebird. There are no previously published reportsof ceived 9 January 2006. Accepted 28 June 2006. Western Bluebirds capturing vertebrate prey, although Western Bluebirds {Sialia rnexicana) are Car'mHealstiVnagllseyNaRtdu.r,alCaHrimsetlorVyalRleeys,erCvaAti9on3,9243,86U0S1A.E. primarily insectivorous during the breeding -Current address: Department ofNeurobiology and season, and rely upon berry crops during win- Behavior, Cornell University, Ithaca, NY 14853, USA; ter (Guinan et al. 2000). Individual Eastern e-mail: [email protected] Bluebirds (Sialia sialis), a congeneric species. SHORT COMMUNICATIONS 129 which is also primarily dependent upon insects DISCUSSION and small fruits (Gowaty and Plissner 1998), Western Bluebirds commonly beat inverte- have occasionally been observed capturing ver- brate prey against a perch before consump- tebrate prey, such as snakes (Flanigan 1971) tion, and both Flanigan (1971) and Pinkowski and shrews (Pinkowski 1974). Beal (1915) re- (1974) reported Eastern Bluebirds beating ver- ported the bones oflizards and tree frogs in the tebrate prey items against perches before con- stomachs of Eastern Bluebirds, as did Bent suming them. The observed bluebird male (1949). Braman and Pogue (2005) found a was clearly treating the lizard as a prey item. dead, 8.3-cm-long flat-headed snake (Tantilla That vertebrate-directed raptorial behavior gracilis) in an Eastern Bluebird nest box, sug- by Western Bluebirds has not been reported gesting a past predation event. Of217 Western previously, despite intensive observation of Bluebird stomachs examined by Beal (1915), Western Bluebird behavior, suggests that, sim- not one contained evidence of vertebrate prey. ilar to Eastern Bluebirds, Western Bluebirds Herlugson’s (1982) analysis of Western Blue- rarely capture vertebrate prey. To my knowl- bird stomach contents similarly yielded no ev- edge, capture of vertebrate prey by the third idence of vertebrate prey items, and adults member of the genus Sialia (i.e.. Mountain were not observed delivering vertebrate prey to Bluebird, Sialia currucoides) has not been re- nestlings. Gaylord (1995) observed a male ported. Western Bluebird carrying an unidentified lizard in his bill; however, she did not observe ACKNOWLEDGMENTS the capture or consumption ofthe lizard. There have been no previous reported observations of 1 thank J. L. Dickinson, D. L. Kleiber, W. M. Fair, Western Bluebirds capturing vertebrate prey. and three anonymous reviewers forproviding valuable comments on this manuscript. OBSERVATIONS LITERATURE CITED Western Bluebirds have been color-banded and their breeding biology monitored at Has- Beal, F. E. L. 1915. Food ofthe robins and bluebirds tings Natural History Reservation, Carmel ofthe United States. U.S. Department ofAgricul- Valley, California, since 1983 (Dickinson et ture Biological Survey Bulletin 171. al. 1996). While censusing a winter group on Bent, A. C. 1949. Life histories of North American thrushes, kinglets, and their allies. U.S. National 11 October 2005, 1 observed a first-winter Museum Bulletin 196. male Western Bluebird catch a ~5-cm-long Braman, S. C. and D. W. Pogue. 2005. Eastern Blue- western fence lizard {Sceloporus occidentalis; bird provisions nestlings with flat- headed snake. Stebbins 1966) in his bill at 0928 hrs PST. The Wilson Bulletin 117:100-101. bluebird was perched on top of a wooden Dickinson,J. L., W. D. Koenig, andF A. Pitelka. 1996. fence post, and the lizard was clinging to the Fitness consequences of helping behavior in the side of the post ~7 cm below the bluebird. Western Bluebird. Behavioral Ecology 7:168-177. Flanigan, A. B. 1971. Predation on snakes by Eastern The bluebird left his perch, hovering briefly Bluebird and BrownThrasher. Wilson Bulletin 83: beside the post as he seized the lizard around 441. its middle with his bill. This maneuver was Gaylord, S. 1995. Lizard cuisine. Sialia 17:65. executed quickly, and the lizard did not at- Gowaty, P. A. andJ. H. Plissner. 1998. Eastern Blue- tempt to flee, although it arched its body after bNiurmdb{eSrial3i8a1.sialis). The birds of North America. it was already held in the bluebird’s bill. Re- Guinan, j. a., P. a. Gowaty, and E. K. Eltzroth. turning to his perch on the same fence post, 2000. Western Bluebird {Sialia mexicana). The the bluebird twice beat the lizard’s head birds of North America. Number 510. against the post. This appeared to be an at- Herlugson, C. j. 1982. Food of adult and nestling tempt to stun or kill the lizard. At 0930 hrs, Western and Mountain bluebirds. Murrelet63:59- the bluebird flew with the now immobile liz- 65. Pinkowski, B. C. 1974. Predation on a shrew by an ard still in his bill onto the property of a pri- Eastern Bluebird. Wilson Bulletin 86:83. vate ranch. I was not able to follow and as- Stebbins, R. C. 1966. A field guide to western reptiles certain whether the bluebird consumed the liz- and amphibians. Houghton Mifflin Company, ard because this ranch is closed to researchers. Boston, Massachusetts, USA.