Bilsa Bird Survey Report





	Survey of the Birds of the Bilsa Biological Reserve extracted from the report by: Jon Hornbuckle 30 Hartington Rd Sheffield S7 2LF & Andrew Mudd 53 Wytham View Eynsham Oxford OX8 1LY For further details contact the authors. Summary A surbey of the birds in the Jatun Sacha Bilsa Reserve, situated in the Mache-Chindul hills of northwest Ecuador (0°22'N, 79°45'W), was undertaken in September 1996 by Karl Berg, Jon Hornbuckle and Andrew Mudd. Although the third such survey of the region, it was the first to be carried out in the 'dry' season and to employ mist-netting. The presence of a number of Andean species and Choco endemics was confirmed, and 35 species added to the Reserve list including the rare Banded Ground-Cuckoo, Saphire Quil-Dove and Tooth-billed Hummingbird. The importance of this reserve cannot be over-estimated. Contents Introduction Objectives Methods Results Discussion Recommendations Acknowledgements References Bird List Return to index The situation in the Mache Chindul mountains of western Ecuador is indeed desperate......this is classified as one of the top three urgent world sites, together with the Atlantic forest of Brazil and Madagascar - World Parks Endowment, 1996. Introduction The wet Pacific forest of northwest Ecuador is one of the most biologically divers and threatened ecosystems on earth. The importance of the forests which still remain lies in the large number of species and high level endemism which they support. It has been estimated that 6300 species of vascular plants occur in western Ecuador as a whole, of which 20% may be endemic (Dodson and Gentry, 1991). Birds show comparable levels of species richness and endemism, with more than 800 species known to occur in western endemics. The region encompasses two important areas of bird endemism - the Tumbesian which contains more than 40 species and the Chocoan which contains more than 30 endemics. Birdlife International considers 15 species which occur primarily in western Ecuador to be threatened with extinction (Collar et al., 1994) The hills of Mache and Chindul, which lie at the northern end of the coastal hill range, contain the last relatively extensive tract of tropical humid forest in the coastal region. The area was the subject of a reconnaissance visit by one of the expedition members in 1991, when it was estimated that about 100 square kilometers of undisturbed forest remained (Mudd, 1991). The area was being deforested at an alarming rate, with perhaps 50% having been cleared between 1980 and 1991. Also in 1991, the Rapid Assessment Program team of Conservation International spent nearly six days surveying the Cabaceras de Bilsa on the western side of the Mache Mountains (Parker and Carr, 1992). They found the forest to be rich in birds, with ca. 160 species, and to contain a number of tree taxa new to Ecuador including one in a genus new to science (Gentry, 1992). In 1994 Fundacion Jatun Sacha established a small biological reserve in the Mache hills. It was called Bilsa, although some 30 km east of Cabaceras de Bilsa, and has been expanded since then, with Jatun Sacha continuing to be actively engaged in land purchase. The nw station serves as a field centre both for Jatun Sacha's own botanical work, and for studies by a range of other field scientists. A visual and audial survey of the birds and large animals, involving 260 field hours, was undertaken in February 1994 by Project Esmeraldas 94, a team of Cambridge University students (Clay et al., 1994) The climate of the Mache-Chindul region is seasonally rainy, but the higher hills, which reach up to about 700m are cloud covered and wet all year round. Of this type of wet/moist forest which once covered 55% of western Ecuador, less than 5% remained in 1988 and the figure is now variously estimated as between only 1 and 3%. At the highest elevations the vegetation is characterised by a profusion of epiphytes, climbers and mosses, forming a type of cloud forest which is unusual for this relatively low altitude. The Bilsa Biological Reserve now occupies 2100 ha within the last relatively extensive block of forest in the northern coastal hills. Plans to extend the reserve to 5000 hawill encompass virtually all the remaining primary forest here. The reserve occupies the headwaters of the rivers Dogola, Cube and Aguacatal with an elevation ranging from 300 to 700 m. Cerro de los Guerilleros, lying on the northern side of the Dogola River and which is probably the highest hill in the region (725m), is now mostly within the reserve. The station itself is at about 550 m. The terrain is extremely difficult but several trails criss-cross the area. The Yellow Trail descends to the headwaters of the Rio Dogola from 600-300 m; the Red and Green Trails both descend into the Aguacatal valley - the Red Trail 650-500m and the Green Trail 550-400m. The Blue Trail links the two. There is also a short path to the headwaters of the Rio Cuba (Piscinas Trail). Most of the reserve is prinary forest although there are areas of secondary forest and scrub, particularaly close to the station itself, which is being replanted with primary forest species. Return to index Objectives To undertake a fairly rapid evaluation of the birds present, to show the biological importance of the reserve with respect to biological diversity, richness and endemism. To determine the conservation status of any endemic forms thought to be threatened with extinction. To use the results to increase awareness of the potential losses to Ecuador and the world if this region is not adequately protected. Return to index Methods Two basic methods were employed - observation, both visual and audial, and mist-netting. Some 300 man-hours of fieldwork was expeded by the two experienced team member. The majority of observations were made from forest trails, one or more of which were traversed daily. A limited time was also taken in overlooking the canopy during the rare periods of clear weather, either from the road bordering the reserve or the veranda of the Field Director's house. A few hours were spent observing from a high platform in the canopy, but without great reward. Although heavy rain was exceptional, visiblity was frequently poor due to thick mist, especially during the first hours of daylight. Nocturnal work was minimal due to the generally inclement weather at night and the hazardous conditions of the forest trails. There was normally a total absence of moonlight. Quantification of species populations by transect or point coins was not attempted due to the short period of the survey and the effort pu tinto mis-netting, plus the team's relativele unfamiliarity with many of the vocalizations. A number of mist-netting stations were established, involving 70m of nets in represntative habitats. They were operated most days for 11-12 hours from dawn to dusk, except when moved between sites which happened every two to four days. Most birds caught, except for sporophila, were banded with metal rings kindly donated by Copenhagen Museum: all were weighed and wing lengths recorded, and one or more representatives were photographed. Lengthy discussions were held with Jatun Sacha staff, particularly the rangers, to learn from their experience. Return to index Results The survey recorded 202 species, adding 35 species to the reserve list, including the globally threatened Banded Groun-Cuckoo and the scarce Sapphire Quail-Dove, Red-masked Parakeet, Tooth-billed Hummingbird and Ocellated Antbird. A total of five species "threatened" with extinction, according to Birdlife International (Collar et al., 1994) was located, along with seven "near-threatened" species. A further 7 Choco endemics were added to the Bilsa list, bringing the total up to around 30 (depending on what is accepted within this classification), compared to only 4 Tumbesian endemics. A total of 488 birds were trapped by mist-netting and the majority ringed/banded. Because of the timing of the survey, there was very little breeding activity and no North American migrants. Only 14 diurnal aptor species were noted, largely attributed to the unfavourable weather conditions. Understory and canopy flocks were few in number. Return to index Discussion The results of the survey have reinforced the view that the Bilsa reserve is of international importance, hosting at least 13 Red Data Book species including five threatened with extinction. At least one additional species is expected to be located in the area, namely Ochraceous Atilla, Atilla torridus, and other scarce species may also be found in the future such as Pacific Royal Flycatcher Onychorhynchus occidentalis, Scarlet-breasted Dacnis Dacnis berlepschi, Scarlet-browed Tanager Heterospingus xanthopygius, and Scarlet-and-white Tanager Heterospingus salmoni. The avifauna is clearly very rich in diversity, with over 250 species, and a high level of endemism of 13%. Most of the endemics have ranges restricted to the Choco region, i.e. extreme eastern Panama through western colombia south to northwest Ecuador (Cracraft, 1985), one of the most threatened endemic centres in the Neotropics due to widespread deforestation. The Choco influence is to be expected as the region is characterized by wet and humid lowland forest, as at Bilsa, whereas Tumbesian forest is generally much drier. What was not anticipated originally was the Andean element of the Avifauna: range extensions have been found for at least 19 species previously thought to be restricted to the Andes or further south in the coastal cordillera, namely Barred Hawk, Red-winged Parrotlet, Green-crowned Brilliant, White-eyed Trogon, Red-faced Spinetail, Scaled Fruiteater, Long-wattled Umbrellabird, Golden-winged Manakin, White-throated Spadebill, Ornate Flycatcher, Spotted Nightingale-thrush, Yellow-bellied Siskin, Golden-bellied Warbler, Chestnut-capped Brush-finch, Yellow-throated Bush-tanager, Silver-throated, Ochre-breasted and Emerald Tanagers, and Black-winged Saltator. Hence the Bilsa surveys have made a significant cntribution to knowledge of the distribution of bird species in northwest Ecuador. Return to index Recommendations The most important action must be to continue to protect and expand the reserve as Jatun Sacha has so successfully done thus far, and to continue to strive for government commitment to establish protected status for all the remaining forest in the Mache Chindul hills. International support fot the latter should continue to be vigorously sought. The following ornithological priorities are recommended: To study the ecology of the Banded Ground-Cuckoo, to determine possible reasons for its rarity and what can be done to assist its survival. To continue to survey the avifauna, especially in the new parts of the reserve and at different times of year, e.g. to determine whether altitudinal movement occurs. Production of new trails would be an advantage here. To establish a systematic mist-netting and banding programme throughout the year. The living facilities of the station were being upgraded as we left, a better washing facility being a high priority. Another useful move, to attract more visitors and thereby bring in more money, would be to improve the condition of the trails, e.g. by putting in boardwalks over the most hazardous stretches. Return to index Acknowledgements Mache-Chindul 1995 was funded by a Birdlife International/FFPS BP Conservation Expedition Award whose generosity is acknowledged. Thanks are also particularly due to the staff of Birdlife International both in Cambridge and Quito, CECIA and Fundacion Ornithologica del Ecuador, who facillitated the necessary permitd, Mike McColm, the director of Fundacion Jatun Sacha, Cyrus Bramme, the ffield director at the Bilsa station and to other Fundacion Jatun Sacha staff at Bilsa. Jon Fjeldsa and Jan Bolding Kristensen (Centre for Tropical Diversity, Zoological Museum, University of Copenhagen) kindly provided the metal rings used in the mist-netting fieldwork. Return to index References Bilby, C. J., Collar, N.J., Crosby, M.J., Heath, M.F. Imboden, Ch., Johnson, T.H., Long, A.J., Stattersfield, A.J., and Thirgood, S.J. (1992) Putting biodiversity on the map: priority areas for global conservation. Cambridge, UK: International Council for Bird Preservation. Clay, R.P., Jack, S.R. and Vincent, J.P. (1994) A survey of the birds and large mammals of the proposed Jatun Sacha Biological Station, Bilsa, NW Ecuador. Preliminary report of Project Esmeraldas 94. Unpublished. Clements, J.F. (1991) Birds of the world: a checklist, 4th Edition. Vista, Calofornia: Ibis Publishing Company. Collar, N.J., Gonzaga, L.P., Krabbe, N., Madrono, Nieto, L.G., Parker, T.A. and Wege, D.C. (1992) Threatened birds of the Americas: the ICBP/IUCN Red Data Book Cambridge, UK: International Council for Bird Preservation. Collar, N.J., Crosby, M.J., and Stattersfield, A.J., (1994) Birds to watch 2: the world list of threatened birds Cambridge UK: Birdlife International (Birdlife Conservation Series no 4) Cracraft, J. (1985) Historical biogeography and patterns of differentiation within the South American avifauna: Areas of endemism pp 49-85 InNeotropical Ornithology Washington D.C.: American Ornithologist's Union (Orn Monogr. 36) Dodson, C.H. and Gentry, A.H. (1991) Biological extinction in western Ecuador Ann. Missouri Bot. Gard. 78:273-295 Hilty, S.L., and Brown, W.L. (1986) A guide to the birds of Colombia. Princeton University. Mudd, A. (1991) Report on an environmental reconaissance of the mountains of Chindul and Mache, northern Manabi and Southern Esmeraldas provinces, coastal Ecuador Unpublished. Equafor Ecoweb Publication click here. Parker, T.A. and Carr, J.L. Eds (1992) Rapid Assessment Program: status of forest remnants in the Cordillera de la Costa and adjacent areas of southwestern Ecuador Conservation International. Ridgely, R.S. and Tudor, G. (1989) The birds of South Amaerica, 1: the oscine passerines University of Texas Press. Ridgely, R.S. and Tudor, G. (1994) The birds of South Amaerica, 2: the suboscine passerines University of Texas Press. Sibley, C.G. and Monroe, B.L. Jr (1990) Distribution and taxonomy od birds of the new world Yale University Press Stattersfield, A.J. and Thirgood, S.J. (1992) Key areas for threatened birds in the neotropics. International Council for Bird Preservation. (Birdlife Conservation Series no. 5) Putting biodiversity on the map: Priority areas for global conservation International Council for Bird Preservation. Wege, D.C. and Long, A.J. (1995) Return to Home Page: