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THE STATUS OF THE PIURÍ (Crax globulosa) IN COLÓMBIA - A BRIEF OVERVIEW
Sara E. Bennett
Bol. CSG 10:18-21 (2000)
Instituto de Investigación de Recursos Biológicos Alexander von Humboldt; A.A. 53200; Santafé de Bogotá, COLOMBIA
The Wattled Curassow (Crax globulosa) is the least known of the curassows that occur in the Colombian Amazon, and there is no protected area in the country with a confirmed population of the species. This note is intended as a first step in addressing the apparent dearth of hard data about its status and regional biology.
This account is a synthesis of conversations with local inhabitants from: 1) the lower Caquetá and Apaporis Rivers, accrued casually over the last 15 yr when I lived there, where the species is called "camarana" in local Spanish and "matacú" in Yucuna; and 2) from short trips in 1991 and 1999 to an area upriver of Leticia along the Colombian side of the Amazon, where its common Spanish name is the onomatopaeic "piurí" or "guaiyú" in Ticuna. I emphasize that the information is entirely anecdotal. Nevertheless, it presents a consistent and coherent picture of a species whose status appears to be not only far more precarious in the country than distribution maps might imply, but also an especially good candidate for potentially effective investment in a single-species conservation program.
DISTRIBUTION IN COLOMBIA
According to Hilty and Brown (1986), C. globulosa occurs throughout most of the Colombian Amazon up to 300 m. The only firsthand observations I know of, though, are from Isla Mirití in the R. Caquetá (part of the Resguardo Indígena Mirití at the mouth of the R. Mirití-Paraná; C. Yucuna, A. Yucuna, B. Bock, V. Páez, pers. comm.) and from Isla Mocagua in the R. Amazonas. It apparently occurs on I. Cacao, a nearby Peruvian island as well. Casual, long-distance inquiries have resulted in no direct information about the species in the R. Putumayo area of the country.
Of the Colombian islands in the Amazon, I. Mocagua is apparently the only one that currently supports a piurí population; on the others, which are mostly larger and closer to Leticia, hunting and habitat destruction have led to local extinctions.
The natural history information reported in subsequent sections refers to I. Mocagua (and I. Cacao). Since the large Amazonian affluents are biogeographically and hydrologically unique, future comparisons of the behavioral ecology and population genetics of populations in each river system will be especially interesting and necessary for designing an overall conservation strategy for the species.
DESCRIPTION OF ISLA MOCAGUA
Isla Mocagua (~10 x 2.5 km = ~2000 ha) is adjacent to Amacayacu National Park at 3º53'S, 70º15'W, with the major axis oriented parallel to the river's current. Though close to the park's main visitor center, the island belongs to and is managed exclusively by the three indigenous communities just down river from R. Matamatá, (the park's eastern boundary): Mocagua, Macedonia, and El Vergel. There are ~250 - 350 people in each community, most of whom are of the Ticuna ethnic group. The island is divided politically into three areas, each of which is specifically associated with one of the communities.
The island is nearly completely inundated when the Amazon R. floods in late April/early May. The vegetation is still mostly natural, consisting of Várzea and Igapó habitats; no one lives on the island. There are several large lakes in the island's interior, whose waters mix with the river's during high-water months, and which are isolated from the river during low-water periods (see Prieto et al. 1995, Duque 1993, and Bahamon 1994 for more detailed vegetation and limnological data).
The main current human uses of the island are: 1) ~30 chagras, or small plots, for cultivating subsistence crops (e.g., manioc, plantains, corn, rice, beans, papaya, watermelon, etc.); 2) for tourist excursions to see the giant water lilies (Victoria amazonica) and other island specialities such as hoatzins (Opisthocomus hoazin) and black caiman (Melanosuchus niger); 3) for (mostly) subsistence hunting, especially of capybara (Hydrochaeris hydrochaeris), tortoise (Geochelone denticulata), muscovy duck (Cairina moschata), and, when encountered, the piurí (Crax globulosa); and 4) for illegal commercial and subsistence fishing by Peruvians in the lakes during low-water months.
The apparent natural history of Crax globulosa on I. Mocagua (and I. Cacao) reflects both the productivity and the seasonal dynamics of the Amazon River. June is the peak month for male reproductive displays and nesting. There may be a short reproductive peak in December as well, but this seems more open to question. Some interviewees said that piurís live in pairs, and that the female alone incubates a clutch of 2 - 6 eggs; another person thought that various females lay 2 eggs each in a single nest and that the male and all females participate in the incubation. E. León indicated that in July 1991 he captured 3 chicks < 2 weeks of age, from a group comprised of 1 male, 3 females, and 5 chicks. A polygamous mating system in the piurí would be a behavioral adaptation consistent with rich and spatially-concentrated food resources.
HABITAT ASSOCIATION AND USE
In both the R. Caquetá and Amazon area accounts there was general agreement that piurís occur exclusively on the large islands of these large whitewater rivers.
On I. Mocgua, the waters of the lakes recede in September and the piurís forage on the exposed mud banks and in shallow puddles for fish, crustaceans, insect larvae, and other invertebrates. This animal prey is abundant, protein-rich and easily-harvested; moreover there is little wild fruit at this time, although they take advantage of what they can find in the chagras (e.g., watermelon rinds) from September to December, as well as sunning and dust-bathing in these openings. From December through April, as the river inundates the island, there is a peak of fruit and seed availability in the flooding forests, for which the piurís forage in the canopies. The relatively short tarsus length of this curassow relative to others probably represents a morphological adaptation to the necessity to be almost entirely arboreal during part of the year, in the absence of terra firma.
POPULATION STATUS ON ISLA MOCAGUA
The older residents on I. Mocagua remember an astonishingly dense population of the piurí (~1000 individuals) as recently as the 1950's. This situation is so different from that typical of upland curassows that it was only the consistency and independence of these anecdotal accounts that finally convinced me of their credibility. To cite one interviewee, B. Vásquez (pers. comm.), "There used to be groups of up to 30 individuals in those days - as you approached, they'd flush like the pigeons in Leticia". Hennessey (1999) reports the species was very common all along the Beni River in Bolivia as well.
In 1991 they estimated that 3 - 25 piurís were hunted on I. Mocagua (Bennett Defler 1991); at least 4 were killed in 1998 (G. and J.C. Arras pers. comm.). The current estimate is that the total population does not exceed 50 individuals. A typical group now consists of 2 - 4 individuals, with females more common than males; interviewees are uncertain whether the sex ratio is naturally biased, or whether more males are hunted. Although piurís are killed opportunistically, the remaining birds are now so scarce and so wary that they are difficult to encounter or approach and it's not worth it to hunt them specifically.
OVER-HUNTING AS A PRINCIPLE THREAT
Adult curassows in general seem to be long-lived in the wild where they are not hunted; C. globulosa in captivity can reach 25 - 30 years of age (Plassé et al. unpubl.). There was general agreement that natural predators are probably not a significant source of mortality for this population. Humans, in contrast, seem to have played the major role in determining current piurí numbers in the area.
The indigenous culture that used to occupy the Colombian shores of the Amazon when white influences first began to be felt strongly in the area has disappeared and been replaced by Ticunas, who previously inhabited only more inland areas (S. Kendall pers. comm.). It is interesting in this context that Mitu tuberosa is the only curassow alluded to in an ethnographic analysis of hunting in nearby San Martín, a traditional upland Ticuna community (Campos 1987).
Until about 1950 the piurís on I. Mocagua were harvested for their meat and for the white venter feathers of the males. The birds were hunted with blowguns, or trapped using corn or manioc bait. According to one account from this period, a white man named Rafael Bandorraga contracted ~30 local men to harvest rubber for him. For ~4 yr it became a custom to hunt 10 - 15 piurís on Sunday to eat during the week. Another account referred to the impact of a commercial animal supplier named Michael Tsalikis (AKA "Mr. Mike"), who bought just about any kind of wildlife, including piurís, for resale abroad. All interviewees agreed that during this period, when shotguns replaced traditional hunting practices, a drastic, precipitate reduction in piuri numbers began.
CONSERVATION OUTLOOK AND FUTURE RESEARCH
C. globulosa appears to be the most stenotypic of the curassows with respect to habitat use. The areas to which the species seems restricted are precisely those most accessible and useful to humans, and thus the most intervened of all Amazonian habitats.
Most of the people with whom I talked seem to expect that the piurí will go extinct sooner or later; there is widespread resignation that once-abundant natural resources have been and will continue to be overexploited. I am nevertheless hopeful that the same factors that render this species so vulnerable also make it an optimal candidate for intensive, species-specific, and potentially effective conservation investment for both biological and socio-cultural reasons.
Riverine islands represent an intrinsically fragmented and dynamic habitat. Over evolutionary time, piurí populations must have experienced repeated founder events, followed by rapid rates of increase enhanced by the productivity of the várzea system and, possibly, by lower predation pressure on nests and young than that experienced by 'mainland' curassows. In contrast to species without this evolutionary history, the strong natural selection to withstand and overcome critically small population sizes might pre-adapt the piurí to recover without the deleterious genetic consequences often associated with demographic bottleneck events (Gilpin & Soulé; 1986; Ralls et al., 1986). Moreover, with the high densities allowed by high ecosystem productivity, small areas, if appropriately managed, might support populations large enough to be viable indefinitely.
Nearby Amacayacu is the only National Park in the Colombian Amazon that is developing and encouraging ecotourism as a mechanism for achieving sustainable development, despite the challenge of competing with other Amazonian countries whose international reputations are less notorious. In fact, the Leticia region is one of the safest and least-troubled areas of Colombia. The piurí is spectacular, big enough to be seen even by a non-birdwatcher tourist, and, at present, nowhere common. It is thus a good candidate to become a flagship species for Amacayacu, except that it is too rare to encounter predictably. A dense and easily observable population, such as that described half a century ago, could represent a wildlife attraction uniquely and especially associated with this region.
I suggested to the three communities on I. Mocagua that we work together to investigate intensively the biology of the piurí, as a first step in developing a long-term management strategy with the goal of restoring the population to its former levels. Their response was enthusiastically positive, as well as skeptical, due to their experiences with other development proposals that have not lived up to their apparent promise for one reason or another.
The timing is opportune for this program. An official process of land-use planning is underway in the Indigenous Reserve and other communities of the Colombian Amazon. El Vergel, Macedonia, and Mocagua have direct responsibility for what is probably the largest (and possibly the only) remaining population of C. globulosa in Colombia. Moreover, these three communities are responsible for the area best suited for long-term protection of the piurí in the country. The active involvement of these people in developing alternative management options should help to catalyze their informed leadership in the conservation of the piurí and its special habitat, as well as other regional wildlife.
I'm grateful to the many individuals who generously shared experiences and ideas and to the communities of El Vergel, Macedonia, and Mocagua for their hospitality. Support for the 1999 trip came from the Instituto de Investigaciones de Recursos Biológicos Alexander von Humboldt, the Unidad Administrative Especial de Parques Nacionales of the Colombian Ministry of the Environment (especially the Regional de Amazonía/Orinoquía and the PNN Amacayacu team), and Daniel M. Brooks, who also helped revise this manuscript. Thanks.
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