ORNITOLOGIA NEOTROPICAL 20: 99–112, 2009 © The Neotropical Ornithological Society

NEST POACHING IN THE VENEZUELAN INSULAR SUBSPECIES OF THE BROWN-THROATED PARAKEET (ARATINGA PERTINAX)

Irene Zager1,2, Kathryn M. Rodríguez-Clark1*, Jessica R. Eberhard3, Jon Paul Rodríguez2,4, & Pablo A. Millán2

1Laboratorio de Ecología y Genética de Poblaciones, Centro de Ecología, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, 1020-A, . *E-mail: [email protected], [email protected] 2Provita, Apartado 47552, Caracas 1041-A, Venezuela. 3Department of Biological Sciences and Museum of Natural Science, Louisiana State University, Baton Rouge, Louisiana 70803, USA. 4Laboratorio de Biología de Organismos, Centro de Ecología, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 20632, Caracas 1020-A, Venezuela.

Resumen. – Saqueo de nidos en las subespecies insulares venezolanas del Perico Cara Sucia (Aratinga pertinax). – Durante mucho tiempo se ha sospechado el declive del Perico Cara Sucia en las islas venezolanas de La Tortuga y Margarita, debido al saqueo de pichones para el tráfico ilegal de mas- cotas, y por la destrucción de sitios de anidación resultante. Por eso, evaluamos el estatus de las dos subespecies involucradas, Aratinga pertinax margaritensis y A. p. tortuguensis, y examinamos la amenaza que representa el saqueo de nidos. Durante trabajos de campo en 2004, caracterizamos los patrones de los dormideros y sitios de anidación en las dos islas, y estimamos el tamaño poblacional de A. p. margaritensis. En la Isla Margarita, encontramos una población considerable (de por lo menos 1984 individuos), pero los 25 nidos encontrados sufrieron una tasa alta de saqueo (64%) y de destruc- ción (32%). Dado que los ùnicos dos dormideros activos de esta subespecie se ubicaron cercanos a o dentro del Parque Nacional Laguna de La Restinga, que también sufre de presiones antrópicas, nues- tros resultados sugieren que esta subespecie se clasifica en el presente como En Peligro (B1a&b[v]). En La Tortuga, encontramos un número insignificante de A. p. tortuguensis en el este de la isla. Además, cada uno de los seis nidos encontrados mostró evidencias de saqueo regular y repetido. Estos resulta- dos apoyan la clasificación propuesta por otros autores de esta subespecie como En Peligro, aunque técnicamente queda en la categoría de Datos Insuficientes.

Abstract. – The Brown-throated Parakeet has been long suspected to be in decline on the Venezuelan islands of Margarita and La Tortuga, due to poaching of nestlings for the illegal pet trade, and to resulting nest destruction. Therefore, we assessed the status of the two subspecies involved, Aratinga pertinax margaritensis and A. p. tortuguensis, and examined the threat presented by nest poaching. During field- work in 2004, we characterized roosting and nesting patterns on both islands, and estimated the popula- tion size of A. p. margaritensis. On , we found a considerable population (at least 1984 individuals), but the 25 nests found were subject to very high rates of poaching (64%) and destruction (32%). Since the only two active roosts of this subspecies were close to or within Laguna de La Restinga National Park, which is also under anthropogenic pressure, our results suggest that this subspecies clas- sifies presently as Endangered (B1a&b[v]). On , we found negligible numbers of A. p. tortuguensis on the eastern portion of the island. Moreover, all six nests found had signs of repeated, regular poaching. These results support other authors’ proposed classification of this subspecies as Endangered, but technically still leave it in the category of Data Deficient. Accepted 6 December 2008.

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Key words: Aratinga pertinax, Brown-throated Parakeet, La Tortuga Island, Margarita Island, nest poaching, nesting site.

INTRODUCTION been assigned an “urgent” priority (Statters- field et al. 1998). Psittacids are one of the most endangered Brown-throated Parakeets are widespread groups of birds in the world, due to a variety and common throughout their range, usually of threats, including habitat loss and fragmen- below 1200 m a.s.l., in open wooded habitats, tation, competition for resources with (and including savannas, gallery formations, man- predation by) non-native species, hunting for groves, arid scrubs, dry forests, and ranch- feathers and food, and natural disasters (Col- lands (Forshaw 1989, Juniper & Parr 1998, lar & Juniper 1992, Christian et al. 1996, Ben- Hilty 2003). During the day, the parakeets nett & Owens 1997, Snyder et al. 1999). travel in pairs or small groups, foraging for a Among the most important of these threats is wide variety of fruits, flowers, nuts, and seeds the capture of wild nestlings and adults for (Forshaw 1989, Silvius 1995). At sunset, non- the pet trade (Collar & Juniper 1992, Snyder et incubating individuals move to communal al. 1999, Wright et al. 2001). Such poaching roosts, where sleeping aggregations can reach appears to be driven by the attractiveness of dozens to hundreds of birds (Juniper & Parr these birds as pets, lax law enforcement, large 1998, Harms & Eberhard 2003). Roost loca- profit margins, and rural poverty (Thomsen & tions are permanent for some psittacids (e. g., Mulliken 1992, Snyder et al. 1999, Rodríguez Wright 1996), while for others roost locations 2000, Wright et al. 2001). change frequently, and even daily (Bradbury In Venezuela, one of the most widely 2003). A. p. margaritensis roost locations poached psittacid species is the Brown- appear to be stable on the scale of at least throated Parakeet (Aratinga pertinax; Duque et weeks, and in some cases several years al. 2005). Populations of this species are (Harms & Eberhard 2003; V. Sanz unpubl.). broadly distributed across northern South Stable nocturnal aggregations may reduce America and several southern predation risks, allow social interaction and islands, with 14 different subspecies currently the exchange of information on foraging sites, recognized (Forshaw 1989, Juniper & Parr and permit pair-bonding between potential 1998). Seven of these subspecies are found in reproductive partners (Harms & Eberhard Venezuela, and two are insular endemics: A. p. 2003, Munshi-South & Wilkinson 2006). margaritensis on Margarita Island, and A. p. During the breeding season, reproductive tortuguensis on La Tortuga Island (Hilty 2003). Brown-throated Parakeets lay four to seven On Margarita, A. pertinax is sympatric with eggs in holes, usually excavated in arboreal two other native psittacids, the Blue-crowned termite mounds in open areas. Less fre- Conure (Aratinga acuticaudata neoxena) and the quently, they may excavate nests in earthen Yellow-shouldered Parrot (Amazona barbaden- banks or use preexisting holes in trees, man- sis), both of which are threatened (Desenne & groves, fallen palm trunks, or rock formations Strahl 1994, Rodríguez & Rojas-Suárez 1999). (Forshaw 1989, Albornoz & Fernández- In contrast, A. p. tortuguensis is the only native Badillo 1994a, V. Sanz unpubl.). Preferred psittacid on La Tortuga. Both islands are mounds contain an active termite colony and included within the Caribbean Colombia and have an external diameter of at least 50 cm, in Venezuela Endemic Bird Area, which has which parakeets build a c. 22-cm diameter

100 INSULAR ARATINGA PERTINAX NEST POACHING nesting cavity with a bottom-opening throated Parakeets and the threat posed by entrance tunnel (width c. 15 cm; Albornoz & nest poaching. Fernández-Badillo 1994a). A. p. tortuguensis and A. p. margaritensis are METHODS of particular concern due to their limited dis- tributions, and their decline has long been Study sites. Margarita lies 38 km north of the suspected for several reasons (Desenne & Venezuelan mainland, across from the Penín- Strahl 1994). First, anecdotal evidence points sula de Araya (Fig. 1A; Hoyos 1985). It is the to widespread capture of nestlings for the pet largest of the country’s islands (934 km2), and trade on both islands (J. M. Briceño-Linares, J. has at least seven threatened endemic birds Salazar pers. com.). Furthermore, poaching is and mammals (Rodríguez & Rojas-Suárez known to be the most important threat to the 1999). The island is shaped roughly like a other psittacids on Margarita (Sanz & dumbbell, with eastern and western sides con- Rodríguez-Ferraro 2006). Finally, the poach- nected by a narrow sand spit and an associ- ing techniques used on Brown-throated Para- ated lagoon, which are largely keet nestlings appear to destroy limited contained within Laguna de La Restinga nesting sites, which would otherwise be National Park. reused (P. A. Millán pers. observ.). In addition In the past, the known distribution of A. to poaching, nest predation and habitat degra- p. margaritensis included both sides of Marga- dation by non-native species may affect the rita, as well as the nearby small islands of parakeet population on La Tortuga (Desenne Coche, Cubagua, and Los Frailes (Phelps & Strahl 1994), while habitat loss due to 1945; Yépez-Tamayo 1963). However, based human development has the potential to on observations made in 2001, Harms & restrict the availability of roost sites on Marga- Eberhard (2003) concluded that A. p. marga- rita (Harms & Eberhard 2003). At present, ritensis occurs essentially only on the western these subspecies lack specific national protec- side (known as the Macanao Peninsula), and tion, although they are listed in Appendix II in the of La Restinga, and is scarce of CITES (CITES 2008). or absent in the more urbanized east. This It has been suggested that the Brown- accords with others’ observations: although in throated Parakeet dominates the Venezuelan 1995 Brown-throated Parakeets were regularly national trade in parrots simply because it is seen in El Tirano (eastern side), they had dis- the most abundant and thus least expensive appeared from there by 2003 (M. Albornoz psittacid available (Albornoz & Fernández- unpubl.). Individuals were also observed in Badillo 1994b, Duque et al. 2005). However, November of 2003 in Lagunamar (eastern poaching and trade of this species have been side; V. Sanz unpubl.). However, presently, on little studied anywhere within Venezuela, the eastern side, small concentrations are much less on these two islands of particular probably found only in the arid areas close to concern. With this in mind, we hypothesized the connecting sand spit, including the vicin- that the poaching threat to A. p. margaritensis ity of the Sector Orinoco and the Tetas de and A. p. tortuguensis is currently under- María Guevara Natural Monument (V. Sanz appreciated, although population sizes on unpubl.). We therefore restricted our work both islands may be robust at the moment. to these areas and the Macanao Peninsula Therefore, we conducted a preliminary assess- (approximately 315 km2, Fig. 1A), which are ment of the population status of the two Ve- covered mostly with cactus and thorn scrub nezuelan insular subspecies of Brown- (Hoyos 1985). Because this is a distinctive

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FIG. 1. Location of areas surveyed (light grey) and in which potential nests were found (stars) on: (A) Mar- garita Island, and (B) La Tortuga Island. Dark grey areas indicate where roosts were located (Margarita; a: Boca de Pasadero, b: Tetas de María Guevara) or where roosting and additional nesting sites may be located (La Tortuga). Numbers in (A) indicate census observation points: 1 - San Francisco; 2 - Manglar Este 1; 3 - Chacaracual 1; 4 - Chacaracual 2; 5 - Manglar Este 2; and 6 - Boca de Pasadero. and well-known species, we augmented our evidence suggests that parakeets may be more own observations (below) with information frequent in the western portion of the island, from informal interviews with nine local where vegetation is more abundant residents. (Rodríguez & Rojas-Suárez 1999) and where La Tortuga is located 120 km west of limited historical data confirm their past pres- Margarita, off the northern coast of Venezu- ence (Phelps 1945). Due to logistical limita- e-la (Fig. 1B). At 156 km2 it is the country’s tions, only the eastern portion of the island second largest island, and is flat and arid. A could be examined during the present study hiding place for pirates during the 17th cen- (approximately 35 km2, Fig. 1B) tury, today La Tortuga is uninhabited, but fishermen and tourism operators live there Study timing. We tried to conduct fieldwork seasonally, and tourists visit occasionally close to but not in the midst of the breeding (Fundación La Tortuga 2008). As on Marga- season. Nesting areas may be easier to locate rita, we complemented our own observations in the breeding season, but population esti- (below) with informal interviews with two of mates based on roost site counts may be these seasonal residents. To our knowledge, biased downward at this time, since incubat- systematic field studies of A. p. tortuguensis ing individuals and nestlings are excluded have never been made. However, anecdotal from counts (Casagrande & Beissinger 1997;

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Cougill & Marsden 2004). The breeding sea- potential nests were defined as mounds with a son for A. pertinax on Caribbean islands diameter > 40 cm, at least 15 cm above the appears to start after wet season rains, and ground, and without any internal branches to lasts for several months between February prevent nest excavation. Since the Russet- and August (Harms & Eberhard 2003; V. Sanz throated Puffbird (Hypnelus ruficollis) also nests unpubl.). We thus conducted fieldwork on in arboreal termite mounds on Margarita, we Margarita from 21 June to 1 July 2004, which recorded cavities as active or inactive parakeet fell toward the end of the breeding season for nests only if they contained green feathers that year (J. M. Briceño-Linares unpubl.). On and had characteristic bottom-opening incu- La Tortuga, we worked from 5 to 10 March bation chambers. On La Tortuga, nests were 2004, before the start of the rainy season and identified based on physical characteristics, thus probably before the parakeets started interviews of seasonal residents, and the pres- nesting, since only inactive nests were found. ence of eggshells and/or green feathers. Informal interviews with seasonal residents indicated moreover that on this island the Roosts and population census. We used modi- reproductive season usually starts at the fications of previously-established methods beginning of April, with peak activity between to locate roosts and estimate population May and June. size on Margarita (Albornoz et al. 1994; Harms & Eberhard 2003). First, we visited all Nests and poaching rates. We surveyed all Brown- places with reported roosts (except Quebrada throated Parakeet nests found in areas where la Vieja, where a roost was observed in 1994; we observed parakeets, where local residents V. Sanz unpubl.), as well as other places indicated their presence, or where they were identified through interviews with nine local reported by previous studies, with the excep- residents, in order to determine which were tion of the mangroves of La Restinga (Yépez- currently in use. However, the time available Tamayo 1963, Rojas-Suárez 1994b), which we for searching was limited relative to the could not survey for lack of a boat. On Mar- probable variability in roost use by this species garita, this totaled five main locations (Fig. (V. Sanz unpubl.), so small roosts may have 1A), where we invested a total sampling effort been overlooked. We then chose six points of 72.5 person-hours walking approximately near the roosts confirmed as active, and 16 km in nesting areas. On La Tortuga, we observed flying parakeets in the late after- had no confirmed prior information concern- noon and early evening (Fig. 1A). Three ing nesting sites, and so searched for a total of observers visited each point once for three 84 person-hours, hiking approximately 120 hours. For each parakeet group observed, we km throughout the study area (Fig. 1B). More recorded the number of individuals and the rapid hiking was possible on La Tortuga probable destination roost (based on flight because of its flat terrain and lack of vegeta- direction and path). tion. During one of these hikes, a local sea- To avoid double-counting, we then con- sonal resident showed us two nesting areas. sidered data only from observation points To determine poaching rates, we collected where destination roosts could be determined information about each potential nest we definitively. The three observation points found, adapting methods developed for the included in the final population estimate Yellow-shouldered Parrot (Amazona barbaden- (“Manglar Este 1”, “Manglar Este 2” and sis) nests on Margarita Island (Rodríguez- “Boca del Pasadero”) were all located along Ferraro & Sanz 1996; Table 1). On Margarita, the edge of La Restinga’s mangroves, closest

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TABLE 1. Variables recorded for each potential Aratinga pertinax nest.

Variable Description Location Geographic coordinates of the nest

Type of nest Termite mound, tree hollow or cavity in an earth bank . Termite colony status Either alive (with an active termite colony) or dead

Parakeet nest status One of four categories of termite mound: (1) active nest: presence of hatchlings or eggs and green feathers, parakeets seen leaving the cavity, or fresh eggshells and green feathers; (2) inactive nest: presence of old egg- shells and green feathers, excavation typical of the species (see text), and/ or historical use known from interview data; (3) potential nest: without signs of parakeet reproductive activity, but with physical characteristics permitting future use; (4) non-nest: without physical characteristics permitting use as a parakeet nest

Physical damage One of two categories of nest: (1) damaged: with anthropogenic or natural damage sufficient to prevent future use as a nest; (2) intact: without physi- cal damage, or with insufficient to impede future use

Poaching/predation status One of three categories of nest: (1) poached: Any evidence of human poaching, including footprints, bicycle tracks, presence of trash in the surroundings, characteristic holes in the termite mound, presence of a “stair branch” or other means of reaching the nest; (2) predated: presence of some sign of predation by animals, (3) not poached or predated to the active roosts (Fig. 1A). We calculated throated Parakeet reproductive activity in the minimum population size as the sum of 2004. An additional 11 had evidence of para- the total number of parakeets counted at keet reproduction in previous seasons, such these observation points. that 40% of potential nesting mounds were On La Tortuga, since no A. p. tortuguensis used at some point by A. pertinax. However, roosts were found, a similar population cen- 16 of these 25 past or present nests (64%) had sus was impossible. some sign of poaching, as did seven of the 14 nests active in 2004. This implies a poach- RESULTS ing rate of 50% during the reproductive sea- son evaluated. Although we could not survey Aratinga pertinax margaritensis any nests that may exist in the mangroves of La Restinga, we expect any poaching that Nests and poaching rates. All of the parakeets does occur there to be similar or even more nests found on Margarita were in arboreal ter- severe to the five sites we surveyed, since mite mounds. Of the 81 mounds found in the fishermen poach essentially all nestlings of five nesting areas we located, 62 had physical the other parakeet which breeds there, A. characteristics permitting nest construction acuticaudata neoxena (J. M. Briceño-Linares (Fig. 2). Of these, 14 had signs of Brown- unpubl.).

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FIG. 2 Status of arboreal termite mounds found in June 2004 on the Macanao Peninsula, Margarita Island, with respect to Brown-throated Parakeet nests.

In addition to heavy poaching, we also more revealed that parakeet hatchlings were encountered considerable damage to potential worth Bs. 15,000 each in 2004 (roughly US$ 8 or present nests. Twenty-four of the 62 ter- at that time, or the equivalent to one day’s mite mounds with a nest or capable of con- minimum wage), whereas healthy adults were taining one (39%) had severe damage from worth more than twice that amount. Other either natural or anthropogenic causes. Expe- psittacids in illegal circulation at the time were rienced poachers on Margarita typically only worth much more; interviews confirmed that open a small hole in the mound, above the this was because Brown-throated Parakeets nest cavity, in order to check for eggs or nest- are considered less attractive, and also because lings (P. Millán pers. observ.). However, if the they are easier to find and extract, since nests hole is too large and the mound has no active are highly visible and accessible. colony, it becomes unusable as a nest. Informal interviews with local residents Roosts and population census. Of the four A. p. also indicated that poaching of A. p. marga- margaritensis roosts located in 2001 on Marga- ritensis nests is common and increasingly rita (Harms & Eberhard 2003), only two were destructive. Residents reported that poaching in use at the time of this study. Both were may be carried out by several members of a located in mangroves in or near Laguna de la family, including the youngest, which has Restinga National Park (one in Boca del Pasa- made nest destruction even more common. dero and the other north of Tetas de María This coincides with other work indicating that Guevara; Fig. 1A). The other two roosts active the number of poachers in the island has in 2001 (in the Río Mucuy valley and in the grown while their average age has declined town of San Francisco de Macanao) were (Rodríguez et al. 2006). Interviews further- inactive in 2004, even though local residents

105 ZAGER ET AL. indicated that they had been used in at least Combining the extent of occurrence of some of the intervening years. We found no the subspecies (not much greater than 330 evidence for additional roosts within the km2), a maximum estimated population size Macanao Peninsula, including at Chacaracual, of ~4000, and only two known roosts, with a where roosts have been observed occasionally known continuing threat that appears to cut in recent years (V. Sanz unpubl.). However, it reproductive success by at least half, we classi- is possible that some small roosts were over- fied A. p. margaritensis as Endangered, accord- looked. ing to IUCN criteria B1a&b(v) (IUCN 2001). Since only two main roosts were active, a That is, the extent of occurrence was less than relatively comprehensive census was possible 5,000 km2, there were fewer than five roosts, even though simultaneous counts were not. and similar poaching rates in similar species Observations indicated that the parakeets (Rodríguez et al. 2004; Pérez et al. 2006) from the western side of the Macanao Penin- allowed us to infer a probable decline in the sula roosted in the western mangrove site number of mature individuals. This was rein- (Boca de Pasadero), while parakeets that for- forced by the fact that all but one of nine local aged to the east of La Restinga usually people interviewed declared that they noticed roosted in the eastern mangrove site (Manglar a reduction in the number of parakeets on the Este). After arriving, especially after sunset, island relative to 10–20 years ago. The sub- most parakeets did not move from their first species also qualifies as Vulnerable according roosting spot; thus, group size counts from to IUCN criterion C2aii, but the precaution- each of the three final observation points ary principle dictates that the higher risk cate- were considered to be independent, although gory be selected when discrepancies exist a small level of double-counting was still pos- (IUCN Standards and Petitions Working sible. Summing the maximum number obser- Group 2006). ved at each site (Table 2), we estimate that in June 2004 there were a minimum of 1984 Aratinga pertinax tortuguensis Brown-throated Parakeets on Margarita. Nests and poaching rates. Although at the time of Threat status. Although our census produced our fieldwork, the Brown-throated Parakeets an estimate of the minimum, and not total, on La Tortuga probably had not yet begun population size, inferences about the number nesting, we found two areas used in previous of parakeets on Margarita are still possible. years, as evinced by several old egg shells and Clearly, we did not count small, overlooked green feathers. The first, in the mangroves off roosts or individuals still incubating or not yet the coast of Laguna de los Mogotes (Fig. 1B), fledged. However, because of the timing and had three nests in cavities in live trees. The thoroughness of our study, we expect these second, near Laguna de Carenero, contained omissions to be minimal. A more important three nesting burrows under an overhanging factor is the challenge of counting many birds embankment of ancient coral rubble, bringing flying simultaneously, thanks to overlap and the total number of parakeet nests detected to movement, and particularly when they are rel- six. We found poaching evidence in both atively distant. With this principal source of areas: initials were carved in all the nesting bias in mind, we believe that the total popula- tree trunks, and a crude ladder was found tion size of A. p. margaritensis in 2004 was at under the nesting burrows. In contrast to our most twice the minimum number recorded, results from Margarita, we found no termite or approximately 4000 individuals. mounds, with or without nests.

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TABLE 2. Numbers of flying Brown-throated Parakeets observed at six observation sites on the Macanao Pensinsula, Margarita Island. Asterisks indicate observation points closest to identified roosts, used for estimating total minimum population size.

Date Location No. of individuals 06/22/2004 San Francisco 29 06/23/2004 Manglar Este 1* 251 06/24/2004 Chacaracual 1 96 06/25/2004 Chacaracual 2 39 06/26/2004 Manglar Este 2* 112 06/27/2004 Boca de Pasadero* 1733

This small amount of direct poaching mangroves are abundant along the coast (Fig. evidence combined with interview results to 1B). This possibility was reinforced by the suggest that poaching is widespread on the west-to-east flight paths of parakeets that we island: one transient fisherman freely indi- observed in the early mornings in the east- cated that several of his colleagues poached central portion of the island. Without identi- parakeet nestlings, and that they often marked fied roosts, a population census was impossi- nests with their initials to indicate “owner- ble. Nonetheless, we observed at least 100 live ship” of the parakeets nesting there. This is individuals on La Tortuga during this study, consistent with evidence from the similarly although never more than 40 at a time. All isolated , where fishermen were found in the middle and southern por- take up to 100% percent of Yellow-shoul- tions of the study area (Fig. 1B), which are dered Parrot nestlings, in spite of the fact that very dry and open, with scarce spiny and it is a protected naval base with restricted scrubby vegetation. Because they were access (Rojas-Suárez 1994a; Rodríguez-Ferra- observed at separate locations, at different ro & Sanz 2007). The nesting sites we found days and times, we have no way of estimating were close to the coast and thus relatively eas- how many of these might be re-sightings of ily accessible. Given the characteristics of the the same individuals. On the north-eastern nesting sites, the absence of termite mounds (windward) side of the island, vegetation was on the island, and the comments of several scarce and no parakeets were observed. seasonal residents, we agree with Rodríguez & Toward the south-east, parakeets were Rojas-Suarez (1999) that a higher density of sparsely distributed, and were observed most- nests may exist in the mangroves of the ly foraging for food in pairs or small groups south-western coast of the island (Fig 1B). If (of eight or fewer individuals). These results this is the case, it is most likely that they are confirm that the eastern portion of the island also poached heavily, due to their accessibility has a negligible population, such that if large by boat. We thus suspect that the poaching numbers of A. p. tortuguensis do exist, they rate on La Tortuga is also very high, as on must be on the western side of the island. Margarita. Threat status. Previous authors have suggested Roosts and population size. Despite extensive that this subspecies be classified as Endan- searching, we found no roosts in the study gered (Desenne & Strahl 1994) or Data Defi- area on La Tortuga. Roosts may be located to cient (Rodríguez & Rojas-Suárez 1999). We the west, near suspected nesting areas, where confirm that the extent of occurrence of the

107 ZAGER ET AL. subspecies is less than the total size of the able concerning wild parakeet longevity sug- island, and that it most likely experiences gests that they may live up to 20 years, poaching rates sufficient to cause a decline in compared with 30-35 years in larger parrots; the number of mature individuals, both of Forshaw 1989; Rodríguez & Rojas-Suárez which support a classification as Endangered 1994; Rodríguez et al. 2004). This suggests (B1b(v); IUCN 2001). However, prior to a that insular populations of Aratinga pertinax category change from Data Deficient to may be equally or more susceptible to poach- Endangered, further studies must be con- ing as larger insular Venezuelan psittacids. ducted, particularly on the western side of La Tortuga, to confirm that there are fewer than A. p. margaritensis. Our most surprising result five primary roosts. for Brown-throated Parakeets on Margarita was their classification as Endangered DISCUSSION (B1a&b[v]), despite the fact that they clearly continue to be the most abundant psittacid on Nest poaching. Our results indicate that poach- the island. Even with the limitations of our ing probably removes half or more of nest- census, the number of parakeets observed lings from the populations of both insular directly in this study (Table 2) was greater subspecies of the Brown-throated Parakeet in than the total estimated present population of Venezuela, Aratinga pertinax margaritensis and Amazona barbadensis (Rodríguez 2003; J. M. A. p. tortuguensis. Population viability analyses Briceño-Linares unpubl.). However, this rela- conducted for the other Venezuelan insular tive abundance combines with a limited psittacids, Amazona barbadensis and Aratinga extent of occurrence, high poaching and a acuticaudata neoxena, show that these species limited number of roosts to clearly merit this are seriously threatened by nest poaching at a classification. Another of our results raises similar level (Rodríguez & Rojas-Suárez 1994; additional concerns about this subspecies’ Rodríguez et al. 2004). Intense nestling extrac- future: our surveys of potential nests revealed tion alters the age structure of a population, extensive damage (Fig. 2). Although we sus- increasing the proportion of adults and reduc- pect that termite mound availability does not ing juveniles and young reproductive adults presently limit nesting, it may in the future if (Rodríguez & Rojas-Suárez 1994, Rojas- current patterns of deforestation and mound Suárez 1994b; Rodríguez et al. 2004). Because destruction continue (Albornoz & Fernán- adults are long-lived, the population may dez-Badillo 1994a). appear healthy and stable at first, even with In the near future, additional assessments intense nestling poaching. However, the aver- of the population status of A. p. margaritensis, age age of the population gradually increases, their reproductive success, and clutch survival eventually leading to abrupt collapse, when rates should be conducted for successive adults reach senescence and few juveniles take breeding seasons: only such temporal infor- their place. mation can confirm population declines (Pri- The extent to which this scenario applies mack et al. 2001, Wiley et al. 2004). We to Brown-throated Parakeets remains unclear. recommend that simultaneous censuses be The short-term masking of poaching effects conducted at the beginning and end of each is enhanced by a longer adult lifespan, and breeding season, with observation points near smaller psittacids are expected to have shorter currently active roosts. This will facilitate not lifespans than larger ones (Munshi-South & only more precise estimates of population Wilkinson 2006; the scant information avail- size, but also of juvenile recruitment and

108 INSULAR ARATINGA PERTINAX NEST POACHING future population dynamics (Rodríguez 2003). island, focusing on locating roosts, in order to Such simultaneous censuses will require clari- conduct a population census. If the man- fication of roosting patterns within the groves along the south side of the island are in Macanao Peninsula. Our results suggest that fact the main nesting and roosting areas, it will the mangroves of the Laguna de La Restinga, furthermore be important to increase nest a wetland of international importance listed surveys there to better estimate poaching under the Ramsar Convention, are crucial for rates. A. pertinax roosting. According to local resi- dents, and as suspected by previous research- ACKNOWLEDGMENTS ers (Yépez-Tamayo 1963; Harms & Eberhard 2003) and confirmed by the present study, the Funding for this study came from a Rufford mangroves of this national park appear to Master’s Scholarship from the Whitley Laing contain the only permanent roosts on Marga- Foundation, the Women’s International Sci- rita. However, the relative importance of ence Collaboration Program of the US other transient roosts (such as those in Río National Science Foundation/The American Mucuy, San Francisco de Macanao, Chacara- Association for the Advancement of Science cual, and Quebrada La Vieja) can be clarified (AAAS), the Lincoln Park Zoo Field Conser- only via systematic multi-season studies. vation Fund, and the Instituto Venezolano de Investigaciones Científicas (IVIC). We are A. p. tortuguensis. Although our results were grateful to J. Salazar, J. M. Briceño, PRO- insufficient to reevaluate the threat status of VITA, I. Zager, R. Peralta, E. Trejo, and N. this subspecies (cf. Rodríguez & Rojas-Suárez Sánchez for their support and field assistance, 1999), we uncovered additional information and to the staff of IVIC’s Unidad de Infor- supporting its proposed classification as mación Geográfica del Centro de Ecología Endangered (Desenne & Strahl 1994). We (ecoSIG), especially S. Zambrano, for their confirmed that its maximum extent of occur- help with maps. The Oficina Administrativa rence is less than the total size of La Tortuga, de Permisiones and the Oficina Nacional de and found at least two lines of evidence (nest Diversidad Biológica of the Ministerio del observations and interviews) suggesting that Poder Popular para el Ambiente provided the poaching is at levels known to cause popula- necessary permits (Licencia de colecta con tion declines in similar species elsewhere. fines científicos N° 41-0066). J. L. Pérez- Interviews furthermore suggested that Eman, M. Lampo, V. Sanz, A.-A. Weller, and although fishermen still consider the species an anonymous reviewer made valuable sug- to be abundant, they feel that parakeets are gestions which improved this manuscript. now encountered less frequently than in the Finally we thank the Comando de Guardacos- past, supporting the inference of a population tas de la Armada Venezolana and the crews of decline. the PG-33 “Albatros” and the PG-410 We agree with previous conclusions that “Pigarco” for providing transportation to La the collection of more information about A. Tortuga Island. p. tortuguensis should be a high conservation priority (Desenne & Strahl 1994, Rodríguez & REFERENCES Rojas-Suárez 1999). Our results indicate that future efforts to estimate this island’s parakeet Albornoz, M., & A. Fernández-Badillo. 1994a. population should be conducted on the west- Aspectos de la biología del Perico Cara Sucia, ern and southern-central portion of the Aratinga pertinax venezuelae (Zimmer y Phelps

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