martes, octubre 14, 2008
Una serie de eventos afortunados
Aprovecho la ocasión en que presento la mencionada Barga Aliblanca (Limosa haemastica) para compartir con ustedes un reporte que hicimos sobre varias observaciones de principios de Otoño del 2005, que incluyen dos nuevas especies migratorias para la isla Hispaniola y varias especies raras avistadas. Lamentablemente el reporte fue hecho en Inglés para informar a la Sociedad Caribeña de Ornitología (SCSCB por sus siglas en Inglés) quien eventualmente lo publicó en su "Journal of Caribbean Ornithology". Para que tengan una idea, en la Isla solo se había reportado una vez la Barga Aliblanca (ver foto), hacía 75 años cuando se colectaron 3 ejemplares! Que conste para el futuro este reporte de los cimarrones Miguel Angel Landestoy y Pedro Genaro Rodríguez.
NEW MIGRATORY BIRD SPECIES REPORTED FROM HISPANIOLA
Miguel A. Landestoy 1, Pedro G. Rodríguez 1, and Steven C. Latta 1, 2, 3
1 Sociedad Ornitológica de la Hispaniola, Santo Domingo, Dominican Republic
2 Point Reyes Bird Observatory, Petaluma, California
3 Current address: National Aviary, Pittsburgh, Pennsylvania
In a remarkable period of birdwatching, Miguel Landestoy and Pedro Rodríguez of the Sociedad Ornitológica de la Hispaniola recorded two migratory bird species new for the island of Hispaniola. A Swainson’s Thrush (Catharus ustulatus) were seen near the Bahía de las Calderas Natural Monument, and a Scarlet Tanager (Piranga olivacea) was found at Rabo de Gato, Sierra de Bahoruco National Park. In addition, a likely Eastern Wood-Pewee (Contopus virens) and several other vagrants were also seen.
Swainson’s Thrush (Catharus ustulatus).-- Arriving at the Las Calderas Naval Base near Las Salinas de Baní, Peravia Province, Dominican Republic at 0800 on 16 October 2005 following an extended period with weather conditions unfavorable for continued migration, Landestoy and Rodríguez observed birds as they walked along the main road toward the town of Las Salinas and the Bahía de las Calderas. At this coastal site, habitat patches include salt lagoons, commercial salt ponds, open mangroves, dry scrub with cactus and mesquite, and residential gardens. At about 1100, near a house on the west side of the road, Landestoy saw two brownish, chunky birds, with an unusually heavy flight, flying into mesquite scrub. One individual landed close to the ground on dead branches. The bird was identified as a thrush by its relatively long and slender bill, fairly long legs, the relatively long wings and tail, and its erect posture. This thrush was identified as a Swainson’s Thrush by its uniformly olive brown upperparts, white underparts with sides of face, throat and breast washed pale buffy, and dark spotting on the sides of the throat and breast (Figure 1). A distinct buffy eye-ring and lores were unmistakable. Most thrushes on Hispaniola are vagrants or occur at higher elevations (Keith et al. 2003). For example, the somewhat similar Bicknell’s Thrush (Catharus bicknelli) is an uncommon to rare winter resident found primarily in montane broadleaf forest (but see Arendt et al. 2004), but the eye-ring and lores are grayer. The only common thrush on Hispaniola, the Red-legged Thrush (Turdus plumbeus) has slaty gray upperparts; reddish legs, bill, and eye-ring; and conspicuous white tail tips (Latta et al. 2006). Swainson’s Thrush was reported once previously in the Dominican Republic based on a ‘light eye ring’ (Bond 1980), but few other details were provided and this record was subsequently treated as hypothetical (Keith et al. 2003). This species has also been reported from Cuba, Jamaica, the Cayman Islands, and the Bahamas (Raffaele et al. 1998), so its occurrence on Hispaniola is not entirely unexpected.
Scarlet Tanager (Piranga olivacea).-- On 11 November 2005, a first-year male Scarlet Tanager was photographed by Miguel Landestoy at Rabo de Gato on the north side of Sierra de Bahoruco National Park. This constitutes the first verified record for this species on Hispaniola. The tanager was recognized by the stout, pointed, horn-colored bill, yellowish-olive uppers, yellow underparts, and dark wings with distinctive black lesser, median, and greater coverts (Figure 2). The bird was first seen perched in a golden shower tree (Cassia sp.), and later it perched in a guayacan tree (Guaiacum sp.) with many Palmchats (Dulus dominicus). Although this tree bore many fruit, the tanager was not seen eating these fruit, but it did sally from the tree to catch an insect. Like the thrush, the Scarlet Tanager has been recorded elsewhere on many of the Caribbean islands (Raffaele et al. 1998).
Eastern Wood-Pewee (Contopus virens).—Also on 16 October 2005 at the Bahía de las Calderas, Landestoy noticed a small flycatcher perched on a dry stick in a garden on the east side of the road just beyond the Natural Monument office. This bird appeared to be a Contopus pewee and similar to the endemic Hispaniolan Pewee (Contopus hispaniolensis), but the latter species occurs most commonly in pine forests in the mountains and foothills (Keith et al. 2003). The bird at Las Salinas appeared olive above and pale below, with a light dusky wash on the breast and sides, two broad whitish wing-bars, and a partial light-colored eye-ring. The bill was dark above, but the lower mandible was extensively yellowish at its base. This bird was readily discernable from the Hispaniolan Pewee which has darker underparts that are gray with an olive, yellow, or brown wash; usually lacks or has very inconspicuous buffy wing bars; and the bill is usually darker and pinkish at the base of the lower mandible (Latta et al. 2006). Excellent photographs were taken (Figure 3), and the bird was also seen by Rodríguez. Although this bird was suggestive of an Eastern Wood-Pewee because its back appeared tinged with green, contrasting with the more brownish-olive head, and the chest was relatively light with the dusky color of the chest band not extending down the flanks, the species is not reliably separated from the very similar Western Wood-Pewee (C. sordidulus) except by voice (McCarty 1996; Bemis and Rising 1999). The individual seen at Bahía de las Calderas was unfortunately silent. The normal migratory route of C. virens would make this species occurrence in the Dominican Republic far more likely than that of C. sordidulus, and it has been previously reported from many islands of the West Indies (Raffaele et al. 1998). However, C. sordidulus has also been recorded as a vagrant on Cuba and Jamaica (Raffaele et al. 1998). A second similar individual was later recorded near the parking lot of the Natural Monument in mixed vegetation of mesquite, mangrove, and sea grape (Coccoloba uvifera).
Other birds considered vagrant on Hispaniola by Keith et al. (2003) were also recorded at Salinas de Baní on 16 October 2005. These included a Red-eyed Vireo (Vireo olivaceus), previously reported five times on migration; Chestnut-sided Warbler (Dendroica pensylvanica) reported four times previously also on migration; Blackburnian Warbler (Dendroica fusca) reported only four times in the past; and Hudsonian Godwit (Limosa haemastica), this being only the second record since three birds were collected in 1930. More than a week later, on October 24, Landestoy found single individuals of a Contopus spp. and Swainson’s Thrush at this same site, but it is unknown if these were the same individuals remaining through an extended stopover, or additional migrants. Another unusual species seen at Rabo de Gato on 11 November was two Baltimore Oriole’s (Icterus galbula), a rare non-breeding visitor with a dozen previous records from Hispaniola (Keith et al. 2003).
We appreciate the comments provided by Wayne Arendt, Steven Mlodinow, Floyd Hayes, and an anonymous reviewer to an earlier draft of this paper.
Arendt, W. J., J. Faaborg, G. E. Wallace, and O. H. Garrido. 2004. Biometrics of birds throughout the Greater Caribbean basin. Proceedings of the Western Foundation of Vertebrate Zoology 8(1):1-33.
Bemis, C., and J. D. Rising. 1999. Western Wood-Pewee (Contopus sordidulus). In The Birds of North America, No. 451 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Bond, J. 1980. Twenty-third supplement to the Check-list of the birds of the West Indies (1956). Academy of Natural Sciences, Philadelphia.
Keith, A., J. Wiley, S. Latta, and J. Ottenwalder. 2003. The birds of Hispaniola: Haiti and the Dominican Republic. Tring, UK: British Ornithologists’ Union, 293 pp.
Latta, S. C., C. C. Rimmer, A. R. Keith, J. W. Wiley, H. A. Raffaele, K. P. McFarland, and E. M. Fernandez. 2006. Birds of the Dominican Republic and Haiti. Princeton, N.J.: Princeton University Press.
McCarty, J. P. 1996. Western Wood-Pewee (Contopus virens). In The Birds of North America, No. 245 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and the American Ornithologists’ Union, Washington, D.C.
Raffaele, H., J. Wiley, O. Garrido, A. Keith, and J. Raffaele. 1998. A guide to the birds of the West Indies. Princeton, N. J.: Princeton University Press.