Juan I. Areta

Impact of yellow fever outbreaks on two howler monkey species (Alouatta guariba clamitans and A. caraya) in Misiones, Argentina

Two yellow fever outbreaks (YFOs) ocurred in northeastern Argentina between November 2007 and October 2008, seriously affecting populations of two howler monkey species: the brown howler Alouatta guariba clamitans and the black howler Alouatta caraya. Both howlers live syntopically in El Piñalito Provincial Park, Misiones, where four groups (36 individuals) were studied since January 2005. The first dead howlers were found on January 20, 2008, in El Piñalito. Systematic searches found 14 dead howlers within the area (12 from the study groups and two from neighboring groups), with only two young seen on January 25, 2008, and none found since up to December 2008. In October 2008, another YFO hit howler monkey populations from El Soberbio, Misiones. Overall, 59 howlers were found dead in Misiones from November 2007 to December 2008. Thanks to the alert of the howlers death in El Piñalito, a prompt human vaccination campaign started in the area. Wild howler monkey populations from both species are in a delicate situation in Misiones, especially the brown howler, an already endangered species in Argentina and endemic to the Atlantic Forest. If we add the recurrence of YFOs to the reduction of suitable habitat to small fragments, it could be only a matter of time until howler populations disappear from the Upper Paraná Atlantic Forest in Misiones. Am. J. Primatol. 72:475–480, 2010.

A theoretical framework for understanding the ecology and conservation of bamboo-specialist birds

Worldwide, populations of a diverse array of bamboo-specialist birds must respond to the life cycles of typical woody bamboos, which include a long vegetative phase, a short period in sexual reproduction (seeding), and a short period dead. While some bamboo species flower continuously in time, but scattered in space, over different parts of their distribution, others exhibit a single, synchronized mass-seeding event, followed by death over hundreds of square kilometers. Thus, bamboo-specialist birds experience extreme variability in their habitat and food sources, and may pass from a period of overabundant habitat and food resources to a period of extreme resource scarcity. At a community level, bamboo species are out of phase with each other. Masting events of several bamboo species may coincide one cycle, but not the next. The resulting long-term dynamics of bamboo cycles at a community scale will result in a temporal and geographic mosaic of resource availability over very long periods of time, where the initial conditions that any bird experienced may occur only sporadically over centuries and very large regions. We aim to propose a theoretical framework for understanding the population ecology of bamboo-specialist birds and discuss implications for their conservation. Three main diet and life-history strategies of bamboo-specialist birds can be identified based on their natural history. First, insectivorous bamboo specialists that inhabit woody bamboos may be relatively sedentary during the long vegetative growth phase, but they must experience population declines, switch to alternative habitat, or travel widely during bamboo die-off events. They benefit from long-term habitat stability but must face short-term reductions in habitat that do not affect all generations of birds. Second, bamboo seed specialists must rely on an ephemeral source of food available only after large intervals of time at most locations. Since bamboo cycles are typically much longer than the lives of individual birds, there is no chance for seed-specialist birds to learn when and where bamboo seeds will be available in the future. Thus, although bamboo seed availability is ecologically predictable (i.e., seeds are always available after the same length of time at a given place), seed availability is unpredictable to individual birds. During their lifetime, most individual bamboo seed-specialists must face a lack of their preferred food supply, at which time they must wander to survive. And third, mixed strategists usually feed on bamboo shoots, leaves, and insects, but consume bamboo seeds when available. Their life history combines elements of both previous categories: they can benefit from long-term habitat stability like insectivores, and take advantage of masting events like seed specialists. Niche width (degree of specialization) in conjugation with the long-term dynamics of bamboo cycles should determine the degree of nomadism and amplitude of bamboo-specialist population cycles. Nomadism appears to be distributed along a continuum from the temporarily nomad insectivores and mixed strategists to the local and regional nomadic seed specialists. A protected area cannot shelter healthy populations of the most specialized bamboo-seed specialists because they track temporally and spatially unpredictable resources over large temporal and spatial scales. Overall, to effectively protect this ecological system, it is crucial to conserve a network of natural areas capable of providing bamboo in different phases and at different times and places, as well as subsidiary food resources that will allow birds to move away from bamboo patches as they become unsuitable to new, suitable patches.

Species Limits and Clinal Variation in a Widespread High Andean Furnariid: The Buff-Breasted Earthcreeper (Upucerthia validirostris)

Abstract. The Buff-breasted Earthcreeper (Upucerthia validirostris) is endemic to western Argentina, and the Plain-breasted Earthcreeper (U. jelskii, including subspecies saturata in the north and pallida in the south), ranges from northern Peru to northwestern Argentina. They have been considered subspecies, as constituents of a superspecies, and as different species. From north to south, a morphocline, involving an increase of rustiness of the plumage and of ∼15% in bill length, 10% in wing length, and 20% in tail length, links jelskii to validirostris. The cline linking jelskii and pallida is gradual, over ∼1800 km; that between pallida and validirostris is steep, over ∼80 km. The northernmost record of validirostris is from the northern Calchaquies Valley, Salta, northwestern Argentina, a valley surrounded by mountains of up to ∼6300 m above sea level through which the lowest pass is at over 4900 m, forming a barrier between validirostris and the southernmost record of pallida to the north. The song, continuous song, duet, and call of validirostris are structurally indistinguishable from those of jelskiilpallida and from the single available recorded song of saturata. In all playback experiments, validirostris answered by approaching and vocalizing to voices of validirostris and jelskii /pallida and vice versa. Treatment of validirostris as a single species is warranted, and three subspecies can be tentatively recognized: southern validirostris (large, rufescent birds with buff bellies restricted to Argentina), central and northern jelskii (small, pale birds ranging from northwestern Argentina to central Peru), and northern saturata (small, dark, and brownish birds in northern central Peru).

Natural History, Distribution, and Conservation of Two Nomadic Sporophila Seedeaters Specializing on Bamboo in The Atlantic Forest

Abstract. Semelparous woody bamboos flower fairly synchronously and in clocklike fashion after many years, providing abundant and nutritious seeds. However, this resource is ephemeral, localized, and unpredictable from the perspective of birds that feed on those seeds. Birds specializing on bamboo seeds track this food source and are nomadic. We recorded Temmincks Seedeater (Sporophila falcirostris) at 29 localities and the Buffy-fronted Seedeater (S. frontalis) at 23 localities in Argentina, Paraguay, and southeastern Brazil. In these species, nomadism is unassociated with any seasonal factor: birds may persist year round over several consecutive years if the seed supply is constant enough. Most occurrences and all breeding records were related to masting of bamboo; records of isolated birds away from seeding bamboo must represent individuals searching for bamboo patches. We report winter breeding of these species for the first time and demonstrate that the supply of bamboo seeds is the main limitation to their breeding. On a broad spatiotemporal scale, large-seeded bamboos (e.g., Guadua spp.) may function as strong population pumps, small-seeded bamboos (e.g., Chusquea spp.) as maintenance stations. Both species fed mostly on bamboo seeds, occasionally on bamboo flowers, and rarely on alternative food sources. They consumed insects frequently and occurred in mixed-species flocks, especially during autumn and winter. Creation of a network of protected areas is essential to preserve bamboo patches that flower at different times and localities in sufficiently large quantities to guarantee the long-term survival of the peculiarly dynamic populations of bamboo seedeaters.

Taxonomy and Biogeography of the Monte Yellow-Finch (Sicalis mendozae): Understanding the Endemic Avifauna of Argentina's Monte Desert

Abstract. The poorly known Pseudochloris mendozae Sharpe, 1888, has usually been considered a subspecies of the widespread Greenish Yellow-Finch (Sicalis olivascens) of the Andes of Peru, Bolivia, northern Chile, and northwest Argentina. In this work, we present data on morphology, vocalizations, ecology, and distribution supporting the recognition of the Monte Yellow-Finch (Sicalis mendozae) (Sharpe 1888) as a full species. S. mendozae is 10% smaller in size (with no overlap in wing or bill measurements), and its average weight is 80% that of S. olivascens. In comparison with S. olivascens, breeding males of S. mendozae are considerably brighter, lack any olive tinge on the throat and breast, lack any dorsal mottling or streaking, and have a brighter olive rump. In fresh plumage nonbreeding males are similar to four other Sicalis species, differing subtly. Female S. mendozae is closest in appearance to the allopatric Patagonian Yellow-Finch (S. lebruni), differing chiefly by its olive rump. The song, complex song, and calls of S. mendozae are diagnostic, though it also imitates some other birds. S. mendozae is endemic to the arid Monte Desert of western Argentina from western Tucumán south to Mendoza, and is parapatric with S. olivascens of high Andean steppes. Contrary to literature reports, S. mendozae is nonmigratory but may move altitudinally, descending to lower altitudes during winter. We propose the recognition of the Monte Desert as a new Endemic Bird Area, based on the overlap of the geographic ranges of several bird species.

Specialization on bamboo by Neotropical birds

Fil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentina. Universidad del Estado de Luisiana. Facultad de Recursos Naturales Renovables; Estados Unidos