J. V. Remsen

Contribution of River-Created Habitats to Bird Species Richness in Amazonia

A substantial portion (15%) of the non-aquatic avifauna of the Amazon Basin is restricted to habitats created by rivers. These habitats are divided into six categories: beaches and sandbars, sandbar scrub, river edge forest, varzea forest, transitional forest, and water-edge. Lists of species restricted to these habitats are presented; for many of these species, this is the first published information on habitat preferences. As many as 169 bird species in the lowland neotropics may have evolved in Amazonian rivercreated habitats, with 99 of these spreading secondarily to man-made second-growth or to regions outside the Amazon Basin. Neither the Congo or Mississippi basin avifaunas show such a high percent of species restricted to river-created habitats; this difference is almost certainly due to the greater amplitude of seasonal water level fluctuations of the Amazon River and its tributaries and consequent greater extent of riverine habitats. Alteration of seasonal water flow patterns that would destroy these habitats could potentially exterminate 64 species of Amazonian river-created habitat specialists. The use of mist nets to sample bird community composition is discussed. NOWHERE IN THE WORLD IS BIRD SPECIES RICHNESS greater than in the Amazon River basin, both in terms of species inhabiting the region as a whole (Amadon 1973) and coexisting at any given point (Pearson 1977). In comparison with temperate regions, year-round availability of fruit and flowers (Orians 1969, Karr 1971) and very large insects (Schoener and Janzen 1968, Schoener 1971) account for much of the high alpha-diversity in the tropics, with smaller contributions from resources such as army ants (Willis and Oniki 1978), bamboo thickets (Parker and Remsen, ms.), and special foraging substrates (Orians 1969, Terborgh 1980). The large number of Pleistocene refugia within and adjacent to the Amazon Basin (Haffer 1969, 1974; Terborgh 1980) may also contribute to the high regional diversity. The purpose of this paper is to point out the contribution of river-created habitats, developed to a much greater extent in Amazonia than anywhere in the world, to regional diversity of Amazonian

TRUE WINTER RANGE OF THE VEERY (CATHARUS FUSCESCENS): LESSONS FOR DETERMINING WINTER RANGES OF SPECIES THAT WINTER IN THE TROPICS

Abstract Most recent references describe the winter range of the Veery (Catharus fuscescens) as including an extensive area from northern Colombia, Venezuela, and Guyana south to south-central Brazil. Analysis of seasonal distribution of specimen records in South America, however, shows that 91 of 105 specimens were taken during spring and fall, not winter; the remaining 14, taken from 2 December to 20 February, are all from three small areas at the periphery or south of the Amazon basin. Thus, the true winter range is almost completely south and east of the area generally described. The seasonal distribution of specimen records is consistent with observational data from South America and banding data from the Neotropics. Although those data must be treated cautiously, it appears that the true winter range of the Veery is in south-central and southeastern Brazil, an area where habitat destruction threatens many natural habitats, rather than in the relatively undisturbed areas of western Amazonia. Widespre...

PATTERNS OF ELEVATIONAL AND LATITUDINAL DISTRIBUTION, INCLUDING A "NICHE SWITCH," IN SOME GUANS (CRACIDAE) OF THE ANDES

A recently discovered population of Chamaepetes goudotii (Sickle-winged Guan) in the eastern Andes of southern Peru and northern Bolivia is anomalous in its high-elevation (above 3,000 m) distribution; populations from central Peru to not-them Colombia are found generally below 2,100 m. Several hypotheses are evaluated to account for the origin of such an unusual distribution. No evidence for long-distance dispersal or human introduction was found (and previous claims of introduction by ancient civilizations to account for disjunct distributions of two other species of New World birds are disputed). We propose that the current pattern is the result of fragmentation of a once continuous distribution. Hypotheses concerning the cause of the fragmentation and maintenance of the current pattern are evaluated. The relative consistency of elevational distributions of Andean bird species over broad latitudinal ranges (and dramatic differences in species composition with changes in elevation) provides circumstantial evidence against an autecological hypothesis that would propose that ecological requirements are met for C. goudotii only in the two disjunct regions. If potential competitors are restricted to congeners, no support can be found for a hypothesis based on interspecific competition. However, if the field of potential competitors is expanded to include morphologically similar confamilials, a striking pattern of generally nonoverlap- ping distributions in terms of elevation and latitude is revealed. Most striking is the reversal in elevations occupied by C. goudotii and Penelope montagnii. The reliance on interpretation for evaluating competing hypotheses makes such analyses inherently unsatisfying.

Refined colorimetry validates endangered subspecies of the least tern

In contrast to the results of Thompson et al. (1992), refined colorimetry validates three subspecies of Least Tern in North America, Sterna antillarum antillarum (Lesson), S. a. browni Mearns, and S. a. athalassos Burleigh and Lowery. Four of nine color characters exhibited significant seasonal differences, presumably a result of plumage wear and bleaching. The sexes differed in lightness and hue of dorsum and hind neck. Males of S. a. athalassos differed significantly from those of both S. a. antillarum and S. a. browni in lightness of dorsum, and males of S. a. browni differed significantly from those of S. a. antillarum in lightness of hind neck. Females generally showed patterns concordant with males. Because S. a. browni and S. a. athalassos are listed as endangered, the validity of these taxa is important to conservationists and managers. Rigorous systematic methodology and scientific collections of high quality are indispensable to conservation biology.

Hematozoa from passeriform birds in Louisiana.

Blood smears were examined from 935 individuals of 19 migrant and resident bird species collected in Louisiana. Of these, 320 (34.2%) harbored hematozoa. The prevalences of parasites were as follows: Haemoproteus spp. 22.8%, Trypanosoma spp. 6.9%, unidentified microfilariae 5.0%, Plasmodium spp. 3.4%, and Leucocytozoon spp. 1.3%. These data are consistent with other reports from the region. Infections were observed in 33% of the individuals in the 13 migrant species sampled and 33% of the individuals in the 6 resident species.

Bird versus mammal morphological diversity.

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History and tradition, or contemporary ornithology? Why ornithological journals should not have bird names

J. V. REMSEN, JR.,14 JAMES A. KUSHLAN,2 AND BETTE A. LOISELLE3 1Museum of Natural Science, Foster Hall 119, Louisiana State University, Baton Rouge, Louisiana 70803, USA; 2U.S. Geological Survey, Biological Resources Division, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, Maryland 20708, USA; and 3Department of Biology, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Louis, Missouri 63121, USA