Spot-mapping of territories was used to document the restriction of nineteen bird species to thickets of bamboo ( G d u a weberbauerz] in lowland forests in southeastern Peru. These species were defined as bamboo specialists. An additional seven species showed a preference for such thickets, but also used other habitats. These results correspond with previous, qualitative descriptions of the habitat preferences of bamboo specialists. At least four specialists are restricted to thickets throughout their entire geographic range (obligate bamboo specialists); another nine specialists may use other habitats sparingly away from southeastern Peru (near-obligate bamboo specialists); the remaining six species are frequent users of habitats lacking bamboo away from southeastern Peru (facultative bamboo specialists). The nonbamboo habitats used by the 13 near-obligate and facultative specialists are predominantly dense habitats with low canopy cover, including treefall gaps and early successional vegetation along rivers. The obligate and nearobligate specialists generally have small geographic ranges centered in southwestern Amazonia; a few have sister taxa in southeastern Brazil that are also bamboo specialists suggesting a common evolutionary history. The facultative specialists are generally more widespread. Bamboo specialists are more abundant in bamboo habitats than are other bird species in more generalized habitats. RESUMENA travCs de un trazado de mapas de territorios de aves, de tierra baja en un sitio del sureste del Perh, 19 especies de aves heron definidas como especies restringidas a matorrales de bambh (Guadua weberbauerz'). Aquellas especies fueron identificadas como "especialistas de bambli." Siete especies adicionales demostraron una preferencia por tales matorrales de bambli, pero tambiCn utilizaron otros habitats. Estos resultados corresponden a descripci6nes previas y cualitativas, que heron hechas sobre las preferencias de habitat entre las especialistas de bambli. No menos de cuatro especialistas son restringidas a matorrales a travks de la extensi6n geogdfica (usuarios obligatorios de bambh); otras nueve especialistas pueden utilizar escasamente otros habitats lejos del sureste del Perh (usuarios casi obligatorios de bambh); las ultimas seis especialistas son usuarios frecuentes de habitats sin bambh fuera del sureste del Perh (usuarios facultativos de bambh). Los habitats sin bambh utilizados por 10s 13 usuarios casi obligatorios y usarios facultativos generalmente heron habitats mis densos sin cubierta de arboles altos, incluyendo claros en el bosque y vegetaci6n sucesional joven en las orillas de rlos. Los usuarios obligatorios y casi obligatorios generalmente tuvieron pequefias extensi6nes geogrificas, entradas en el suroeste de la Amazonia. Algunas comparten taxa hermanas con especies que tambiCn son especialistas en el sureste de Brasil, lo cual indica una historia evolutiva en comhn. Los usuarios facultativos generalmente tienen distribuciones m h amplias. Las abundancias de 10s especialistas ...

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. American Ornithologists' Union is collaborating with JSTOR to digitize, preserve and extend access to The Auk. Changes in this supplement include the following: (1) one genus (Chrysomus) and eight species (Oceanodroma monorhis, Ixobrychus minutus, Ardea purpurea, Platalea leucorodia, Glareola pratincola, Elaenia albiceps, Luscinia sibilans, and Chrysomus icterocephalus) are added to the main list (including three species transferred from the Appendix) on the basis of new distributional information; (2) the distributional statement of one species (Trogon melanurus) is changed because of a split from an extralimital species; (3) three species are changed (to Melanitta americana, Trogon caligatus, and T. chionurus) by being split from extralimital species; (4) six species (Caprimulgus arizonae, Chasiempis sclateri, C. ibidis, Icterus northropi, I. melanopsis, and I. portoricensis) are added as a result of splits from species already on the list; (5) two species (Troglodytes hiemalis and T. pacificus) are added by being split both from an extralimital taxon (T. troglodytes) and from each other; (6) five species (Melozone fusca, M. albicollis, M. crissalis, M. aberti, and Amphispiza quinquestriata) are transferred to currently recognized genera; (7) five genera (Psilorhinus, Peucaea, Oreothlypis, Parkesia, and Rhynchophanes) are added because of splits from other genera, resulting in changes to 20 scientific names; (8) a new scientific name (Vermivora cyanoptera) is adopted for one species because of a nomenclatural problem with the previous scientific name (V. pinus); (9) the citation for one species (Dendroica pinus) is changed; (10) the endings of the specific or subspecific names of two taxa (Acanthidops bairdi and Vireo gilvus swainsoni) are corrected; (11) the English names of three species (Caprimulgus vociferus, Chasiempis sandwichensis, and Icterus dominicensis) are modified as a result of taxonomic changes, the English name of one species (Puffinus gravis) is modified for global conformity, and the hyphen is removed from the English name of one species (Empidonomus aurantioatrocristatus); and (12) two species (Empidonomus aurantioatrocristatus and Thryothorus sinaloa) are added to the list of species known to occur in the United States.Numerous changes are made at higher levels of the classification on the basis of new genetic data. Four newly recognized orders (Phaethontiformes, Suliformes, Accipitriformes, and Eurypygiformes) are added to the main list by being split from existing 29_Supplement_127-3.indd 726 7/2/10 12:41:48 PM