REGION 2 SENSITIVE SPECIES EVALUATION FORM Species: Least bittern (Ixobrychus exilis) Criteria Rank Rationale Literature Citations 1 B The least bittern occurs in South Dakota, Kansas, and northeastern Colorado. • Distribution within R2 Confidence in Rank High or Medium or Low BREEDING: in western North America in southern Oregon, interior and southern • www.natureserve.org 2 C coastal California, central Baja California, and southern coastal Sonora; in eastern Distribution • citations in references outside R2 North America from southern Manitoba, north-central U.S., southeastern Canada (Ontario and Quebec), eastern Maine, and southern New Brunswick (few records) section south to western and southern Texas, Gulf Coast, Florida, and Greater Antilles; west to central Montana, Utah (Great Salt Lake, formerly), eastern Colorado, and south- central New Mexico; Middle America in Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, and elsewhere, especially Mexico; widely in South America in central Colombia, coastal Peru, and east of Andes from Venezuela and Guianas south to northern Argentina and southern Brazil (AOU 1983, Gibbs et al. 1992). NON-BREEDING: southern California, southern Texas, and northern Florida south through the breeding range in South America (AOU 1983). Largest numbers in southern Florida, Rio Grande valley, lower Colorado River between California and Arizona, Baja California, Greater Antilles, and Central America (Root 1988, Gibbs et al. 1992). Confidence in Rank High or Medium or Low There is no information to suggest that the least bittern has diminished dispersal • 3 D capability. Dispersal Capability Confidence in Rank High or Medium or Low There is virtually no information on the abundance of this difficult to detect migratory • 4 D bird. Abundance in R2 Confidence in Rank High or Medium or Low Species: Least bittern (Ixobrychus exilis) Criteria Rank Rationale Literature Citations There is no trend data for this species other than scattered accounts from the eastern • www.natureserve.org 5 D U.S. There is no BBS data relative to Region 2. In Region 2, the species is at the Population Trend in R2 fringe of its breeding range and that may explain why the least bittern is viewed as imperiled in South Dakota, Nebraska, Kansas, and Colorado. Confidence in Rank High or Medium or Low Jeopardized by draining, filling, and degradation of marshes and probably by • citations in references 6 A environmental contaminants and unnaturally high densities of predators such as Habitat Trend section in R2 raccoons (Evers 1992). May be negatively impacted by high water levels in the Great Lakes (Sandilands and Campbell 1988). Palmer (1962) stated that "...unquestionably, parts of the range have been affected adversely in recent years by marsh drainage, pollution, spraying of insecticides, and other activities of man." In Region 2, the longstanding loss of marshes with suitable emergent vegetation has probably played a role in the decline of the species. Confidence in Rank High or Medium or Low Many programs and regulatory mechanisms are now in place that protect the large • www.natureserve.org 7 B marshes preferred by this species, so habitat may not be as vulnerable as in the past. Habitat Vulnerability or Modification Confidence in Rank High or Medium or Low 8 D • www.natureserve.org Life History and Confidence in Rank High or Medium or Low Demographics Initial Evaluator(s): John Sidle Date: 7/6/01 National Forests in the Rocky Mountain Region where species is KNOWN (K) or LIKELY(L)1 to occur: Colorado NF/NG Kansas NF/NG Nebraska NF/NG South Dakota Wyoming NF/NG NF/NG y y y y y Known Known Likel Likel Known Likel Known Likel Known Likel Arapaho-Roosevelt NF Cimmaron NG Samuel R.McKelvie NF L Black Hills NF Shoshone NF White River NF Halsey NF L Buffalo Gap NG Bighorn NF Routt NF Nebraska NF Ft. Pierre NG L Black Hills NF Grand Mesa, Ogalala NG Medicine Bow NF Uncompahgre, Gunnison NF San Juan NF Thunder Basin NG Rio Grande NF Pike-San Isabel NF Comanche NG 1 Likely is defined as more likely to occur than not occur on the National Forest or Grassland. This generally can be thought of as having a 50% chance or greater of appearing on NFS lands. References American Ornithologists' Union (AOU), Committee on Classification and Nomenclature. 1983. Check-list of North American Birds. Sixth Edition. American Ornithologists' Union, Allen Press, Inc., Lawrence, Kansas. American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, DC. 829 pp. Andrle, R. F., and J. R. Carrol, editors. 1988. The atlas of breeding birds in New York State. Cornell Univ., Ithaca, New York. 551 pp. Aniskowicz, B. T. 1981. Behavior of a male least bittern IXOBRYCHUS EXILIS after loss of mate. Wilson Bulletin 93:395-397. Audubon, J.J. 1840. The birds of America. [Reprint edition. 1967. Dover Publications, Inc., New York. 650 pp.] Bent, A. C. 1926. Life histories of North American marsh birds. Bull. U.S. Nat. Mus. 135. Brewer, R., G.A. McPeek, and R.J. Adams, Jr. 1991. The Atlas of Breeding Birds of Michigan. Michigan State University Press, East Lansing, Michigan. xvii + 594 pp. Brown, M., and J. J. Dinsmore. 1986. Implications of marsh size and isolation for marsh bird management. J. Wildl. Manage. 50:392-397. Butcher, G. 1989. Bird conservation: establishing priorities. Birdscope 3(1):1-3. Causey, M. K., and J. B. Graves. 1969. Insecticide residues in least bittern eggs. Wilson Bulletin 81:340-341. Cogswell, H. L. 1977. Water birds of California. Univ. California Press, Berkeley. 399 pp. Cottam, C., and F. M. Uhler. 1945. Birds in relation to fishes. Fish and Wildlife Service. Leaflet No 272. Cramp, S. (editor). 1977. Handbook of the Birds of Europe, the Middle East, and North Africa; the Birds of the Western Paleartic. Vol. 1: Ostrich to Ducks. Oxford University Press, Oxford, England. 722 pp. Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1992. Birds in Jeopardy: the Imperiled and Extinct Birds of the United States and Canada, Including Hawaii and Puerto Rico. Stanford University Press, Stanford, California. 259 pp. Evers, D. C. 1992. A guide to Michigan's endangered wildlife. Univ. Michigan Press, Ann Arbor. viii + 103 pp. Fleming, W. J., D. R. Clar, Jr., and C. J. Henny. 1983. Organochlorine pesticides and PCB's: a continuing problem for the 1980's. Trans. N. Amer. Wildl. and Nat. Resour. Conf. 48:186-99. Font, W. F., R. M. Overstreet, and R. W. Heard. 1984. Taxonomy and biology of PHAGICOLA NANA Digenea Heterophyidae. Transactions of the North American Wildlife and Natural Resources Conference. 103:408-422. Forbush, E. H. 1925. Birds of Massachusetts and other New England states. Part 1: Water birds, marsh birds and shore birds. Massachusetts Department of Agriculture, Boston, Massachusetts. 486 pp. Frederick, P. C., et al. 1990. Relative abundance and habitat preferences of least bitterns (IXOBRYCHUS EXILIS) in the Everglades. Florida Field Nat. 18:1-20. Fredrickson, L. H., and T. S. Taylor. 1982. Managment of seasonally flooded impoundments for wildlife. Fish and Wildlife Service Resource Publication 148. 29 pp. Fredrickson, L.H., F.A. Reid. 1986. Wetlands and riparian habitats: a nongame management overview. Pages 59-96 in J.B. Hale, L.B. Best, and R. L. Clawson, (eds.) Management of nongame wildlife in the Midwest: a developing art. Proc. Symp. 47th Midwest Fish and Wildl. Conf. Friend, M. 1987. Field Guide to Wildlife Diseases. Vol. 1: General Field Procedures and Diseases of Migratory Birds. Fish and Wildlife Service Resource Publication 167. 225 pp. Gibbs, J. P., and S. M. Melvin. 1992. Least bittern, IXOBRYCHUS EXILIS. Pages 71-88 in K. J. Schneider and D. M. Pence, editors. Migratory nongame birds of management concern in the Northeast. U.S. Fish and Wildlife Service, Newton Corner, Massachusetts. 400 pp. Gibbs, J.P., F.A. Reid, and S.M. Melvin. 1992. Least Bittern (IXOBRYCHUS EXILIS). In A. Poole, P. Stettenheim, and F. Gill, editors, The Birds of North America, No. 17. Academy of Natural Sciences, Philadelphia, and American Ornithologists' Union, Washington, DC. 12 pp. Gibbs, J.P., and S.M. Melvin. 1990. An assessment of wading birds and other wetlands avifauna and their habitats in Maine. Maine Department of Inland Fish. and Wildlife, Bangor, Maine. 61 pp. Unpublished report. Guillory, H.D. 1973. Motor vehicles and barbed wire fences as major mortality factors for the least bittern in southwestern Louisiana. Inland Bird Banding News 45:176-177. Hancock, J., and J. Kushlan. 1984. The Herons Handbook. Croom Helm, Ltd., Kent, England. 288 pp. Hands, H. M., R. D. Drobney, and M. R. Ryan. 1989. Status of the least bittern in the northcentral United States. Missouri Coop. Fish Wildl. Res. Unit Rep. 13 pp. Hansen, S. C. 1984. Breeding of the least bittern in Pottawatomie County, Kansas. Kansas Ornithological Society Bulletin 35:37-39. Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio. Harrison, H. H. 1979. A field guide to western birds' nests. Houghton Mifflin Company, Boston. 279 pp. Herkert, J. R., editor. 1992. Endangered and threatened species of Illinois: status and distribution. Vol. 2: Animals. Illinois Endangered Species Protection Board. iv + 142 pp. Howell, A. H. 1932. Florida bird life. Coward-McCann, New York. Jorde, D. G., J. R. Longcore, and P. W. Brown. 1989. Tidal and nontidal wetlands of northern Atlantic states. Pages 1-26 in L. M. Smith, R. L. Pederson, and R. M. Kaminiski (editors). Habitat management for migrating and Wintering waterfowl in North America. Texas Tech. Univ. Press, Lubbock, Texas. Kent, T. 1951. The least bitterns of Swan Lake. Iowa Bird Life 21:59-61. Kibbe, D. 1989.