Instances of competition for cavities and evidence of predation on Prothonotary Warblers (Protonotaria citria) by Peromyscus spp. (white-footed and cotton mice) were observed at Cocodrie Lake, Evangeline and Rapides parishes, Louisiana. Mice destroyed nests, killed adults and nestlings, and cached food in cavities and nest boxes.

Division of Sciences Louisiana State University at Eunice P.O. Box 1129, Eunice, Louisiana 70535 USA COMPETENCIA POR CAVIDADES Y SOSPECHA DE DEPREDACI(SN EN PRO- TONOTARIA CITREA POR ARTE DE PEROMYSCUS SPP. Sinopsis.--En un estudio que se 11ev6 a cabo en varias localidades de Luisiana, se tom6 evidencia sobre competencia por cavidades entre Protonotaria citrea y ratones del gnero Peromyscus, ademSs de depredaci6n de aves pot parte de los toedores. Los ratones des- truyeron nidos y lograton matar a aves adultas y juveniles; utilizaron cavidades y cajas de anidamiento de las aves para almacenar nueces y semillas. While studying foraging and reproductive behavior of the Prothonotary Warbler (Protorzotaria citrea), I encountered instances of competition for cavities and evidence of predation on the warblers by Peromyscus spp. Prothonotary Warblers use cavities, usually over water, for nest sites (Walkinshaw 1953). White-footed Mice (P. leucopus) and Cotton Mice (P. gossypinus) can occur in swampland (Bates 1958, LeBlanc 1979) and frequently use tree cavities and abandoned birds' nests for nest sites (Davis 1966, Golley 1962, Lowery 1974). These mice are sympatric in Louisiana and common inhabitants of floodplain and upland deciduous forests (St. Romain 1975). The study was conducted at Cocodrie Lake, in Evangeline and Rapides parishes, Louisiana from March through July 1982-1985. This lake is a 2400 ha water tupelo (Nyssa aquatica), bald cypress (Taxodium disti- churn), and buttonbush (Cephalarzthus occidentalis) swamp. To facilitate data collection, I set out 50 modified cans and 24 wooden boxes. These structures were 15-20 cm high and 10-12 cm in diameter with 2.5 cm diameter entrances. The cans and boxes were attached to trees, usually over water, at a height of 1.5-2.0 m. I examined the artificial nest sites on a weekly basis. On 18 June 1982, the partial remains of two, one-week old nestlings were found entangled in nest material that was suspended from the nest can entrance. The rear portion of the skull and much of the proximal portion of the wings had been consumed on one. Only some primary feathers and feet remained from another. The partially dessicated mus- culature of one wing had clearly visible mouse-sized incisor marks. Before sunrise on 24 April 1983, I observed a fleeing adult Peromyscus spp. on the floor of my lakeside cabin. Near where I first observed the mouse, I saw a wing protruding from between the cottage walls at floor level. I extracted a freshly dead adult, male prothonotary with the rear portion of the skull and some wing musculature detached. The warbler had been constructing a nest between the cottage walls and appeared to have been killed while roosting at the site. In 1984, I found evidence of cached food, feeding stations, and visitations in 15 nest boxes and cans in the form of stored laurel oak acorns (Quercus laurifolia) and water tupelo seeds; laurel oak acorn and tupelo seed cut- tings; and urine and fecal pellets. None of these containers were used as nest sites by prothonotaries indicating that Peromyscus spp. successfully competed for these sites with the warbler. In 1985 two nest boxes contained stored or eaten water elm fruit (Planera aquatica). In two other boxes, material from two completed nests, that had not received eggs, had been pulled through the entrances. These nests were not repaired by prothonotaries. A Peromyscus was flushed from a fifth nestbox that contained the fresh remains of a female prothonotary and four untouched eggs. Southern flying squirrels (Glaucornys volans) were eliminated as pos- sible prothonotary competitors because fecal pellets found in nest con- tainers were too small to be from Glaucomys and no flying squirrels were ever found within nest boxes. Maxson and Oring (1978) have reported destruction of Spotted Sand- piper (Actiris rnacularia) eggs by Perornyscus rnaniculatus. Stone and Cram (1902) noted that P. leucopus devoured both eggs and young birds. Nelson (1918) reported that P. leucopus sometimes consumed the flesh of dead birds and mice while Hamilton (1941) found bird remains in the stomachs of P. leucopus and P.rn. gracilus. Cotton and white-footed mice have been reported to consume insects (Baker 1968, Bates 1958, Calhoun 1941) and crawfish (LeBlanc 1979). Walkinshaw (1941) reported nest site competition in Michigan between Prothonotary Warblers, Northern House Wrens (Troglodytes aedon) and Black-capped Chickadees (Parus atricapillus). Although cavity-nesting Tufted Titmice (P. bicolor) and Carolina Chickadees (P. carolinensis) nest at Cocodrie Lake, no competition was observed. Although Perornyscus leucopus and P. rnaniculatus-bird interactions have been documented (I know of no P. gossypinus documentation), previously they were not known to occur with Prothonotary Warblers. The pref- erence for swampy habitat by Prothonotary Warblers has not prevented the adaptable Peromyscus from swimming to their nest sites. The occasional predation on Prothonotary Warblers and competition for cavities by Peromyscus spp. apparently has caused little harm to the overall population of prothonotaries at Cocodrie Lake because they con- tinue to be abundant. ACKNOWLEDGMENTS I thank E. H. Burtt, Jr., j. N. Layne, M. F. Vidrine, and two anonymous reviewers for their helpful suggestions. The Louisiana State University at Eunice Office of Academic Affairs and Services provided financial assistance. LITERATURE CITED B^ICEI, R. H. 1968. Habitats and distribution. Pp. 99-121, in J. A. King, ed. Biology of Peromyscus (Rodentia). Spec. Publ. Amer. Soc. Mamm. 2:1-593. BATES, J. 1958. Studies on Rhoad's cotton mouse, Peromyscus gossypinus rnegacephalus, in Alabama. J. Tenn. Acad. Sci. 33:123-132. C^IHOtJN, J. B. 1941. Distribution and food habits of mammals in the vicinity of the Reelfoot Lake Biological Sta. J. Tenn. Acad. Sci. 16:207-225. D^vIs, W. B. 1966. The mammals of Texas. Texas Parks and Wildlife Dept. Bulletin 41, Austin. Got. IE3/4, F. B. 1962. Mammals of Georgia. Univ. of Georgia Press, Athens. H^MIITON, W. J., jr,. 1941. The food of small forest mammals in eastern United States. J. of Mammal. 22:250-263. LEBI^NC, D.W. 1979. Selected aspects of the population dynamics and ecology of the white-footed mouse (Perornyscus leucopus) and cotton mouse (Perornyscus gossypinus) in south Louisiana. M.S. thesis, Louisiana State Univ., Baton Rouge. LOWEr, Y, G. H. 1974. The mammals of Louisiana and its adjacent waters. 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