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Macaw Behaviour in the Jungles and Savannahs of Bolivia
Catherine Soos, B.Sc., DVM'97
This summer, Laurel Neufeld and I studied the behaviour of wild macaws in the Bolivian jungles and savannahs. In the Amazon, we studied Red-and-Green macaw (Ara chloroptera) behaviour and examined competition for roosting/nesting sites, aggression, pair behaviour, juvenile behaviour, parent-juvenile interactions, anti-predator behaviour, alarm calling, and mutualism. In the savannahs, we observed the behaviour of Blue-throated macaws (Ara glaucogularis), and investigated the use of and competition over artificial nest sites excavated last year in eight dead palm trees.
The Amazon rainforests are home to 16 species of macaws, 6 of which are endangered or on the verge of extinction. These parrots are threatened by humans who disturb their natural habitat, and destroy their nests for the pet black market or for meat and feathers. Many species of macaws remain abundant in certain regions of the Amazon. However, without the help of conservational intervention, these birds can potentially suffer the consequences associated with the pressures that have placed other macaw species on the endangered list.
Over the last two decades, Dr. Charles Munn of the Wildlife Conservation Society and his colleagues have been studying wild macaw behaviour in Perù, Brazil, and Bolivia. Munn's research in Perù has shown, among other things, that macaws possess naturally low reproductive rates that cannot keep up with the various external pressures that decrease their populations. In actuality, only 10-15% of adult macaws successfully reproduce per year. This low frequency is mainly a result of the insufficient number of suitable nesting sites, as well as the fact that eggs and chicks suffer a high mortality rate of 75%. Over the years, Munn and associates have managed to devise successful methods to raise macaw populations in the wild. Furthermore, Munn's work has managed to help conserve over 4 million acres of rainforest land, thereby protecting all the wildlife and plant life within those regions.
Because of the importance of this work and my desire to contribute to it, I contacted Dr. Munn about the possibility of becoming involved with some of the projects he is associated with. Months later I was on a plane on my way to Bolivia, full of anticipation (I could not wait to set my eyes on wild macaws flying above the rainforest canopy) as well as apprehension (I did not know what to expect being a solitary, non-Spanish-speaking, pale-faced city girl accustomed to the luxuries of the cosmopolitan life, like running water, toilets, and electricity). Little did I know that this trip was going to be one of the best learning experiences of my academic and personal life.
I spent the major part of the summer volunteering for a non-governmental organization called EcoBolivia. This group is led by Rosamarìa Ruiz, a very strong, clever, and motivated Bolivian woman who has 40 years of experience in the Bolivian rainforests, and hence an intimate knowledge of the area and the people native to it. The main goals of EcoBolivia are the conservation and active protection of intact, vulnerable areas of rainforest, and the improvement or sustainable development of areas inhabited by native people, particularly those whose families have remained in the regions over generations. EcoBolivia takes pride in their uniqueness in hiring only local men and women who have lived their entire lives in the Bolivian lowlands, and have a vast knowledge of the plant and wildife within the rainforests. EcoBolivia is actively involved in several ongoing projects including the creation of a National Park, the active protection of a large area within the proposed park, the study of wild macaws and other parrots, a census of all the wildlife and plant life within the region, land-titling projects, ethnobotany and ethnopharmacology studies of potentially medicinal plants, and environmental education. EcoBolivia is also presently working with CARE to establish health systems and potable water systems in local rainforest communities.
One of EcoBolivia's major goals is the creation of the 1,800,000 hectare Alto-Madidi National Park in the northwest region of the Department of La Paz. This area is extremely diverse, both in plant life and wildlife, hence the importance of protecting it. By December of 1992, EcoBolivia had diligently followed the steps necessary to get the Park going, and had thoroughly completed the required paperwork. However, negotiations are still underway, and it is basically in the Bolivian government's court to enforce the protection of the proposed Park. Unfortunately, because the area is not presently being protected, its flora and fauna are greatly vulnerable to exploitation and destruction.
The Red-and-Green Macaws of Caquiahuara
I worked in Caquiahuara which is a region located within the proposed Alto-Madidi National Park on the Tuichi River, about a three hour motorized boat ride from the nearest town. In addition to the hundreds of avian species in this area, one can catch glimpses of black mantled tamarins, howler monkeys, common woolly monkeys, tapirs, opossums, spectacled caimans, collared peccaries, white-lipped peccaries, a wide variety of snakes, lizards, turtles, frogs, and toads. EcoBolivia has built a very comfortable biology research station in Caquiahuara consisting of a complete kitchen facility and three sleeping huts containing separate rooms. They have also created a very extensive but non-invasive trail system in and around the area. At the moment, four local men who grew up in the jungle are employed to actively protect Caquiahuara and neighbouring areas from the constantly invading hunters, poachers, and loggers.
One of the most unique things about Caquiahuara is the series of 60 to 90 metre high sandstone cliffs that contain holes that several species of parrots live in. In fact, this area contains a population of 34 Red-and-Green macaws (Ara chloroptera), 26 severe macaws (Ara severa), and 30 white-eyed parakeets (Aratinga leucophthalmos), most of which live inside the cliff holes.
For two months I, along with my colleague, Laurel Neufeld, a biology undergraduate at theUniversity of Manitoba, studied the behaviour of the Red-and-Green macaws that live in the cliffs. We examined things such as competition for the cavities, territoriality and aggression, antipredator behaviour, juvenile behaviour, and social behaviour. Social behaviour includes pair behaviour, juvenile-parent interactions, calling behaviour, and mutualism.
On average, four pairs of Red-and-Green macaws were within their cavities at any one time during the day. While sitting at the entrance of their cavities, pairs roosted quietly, occasionally preened each other, or loudly called out to other macaws in the cliff, nearby trees, or neighbouring cliffs. Members in a pair almost always remained with each other, and flew away from their cavity together to feed or socialize in nearby trees. Every day at dusk (by 6:30pm), all pairs that lived in the cliff returned to their cavities where they spent the night. At dawn, pairs began leaving the cliff to go foraging, and most pairs were gone by 7:30am. Some pairs did not return until dusk, while others intermittently returned and departed for various lengths of times throughout the day. The time of day that we observed the highest number of macaws roosting within their cavities was in the afternoon from 4:00 pm until darkness.
Competition, Territoriality, and Aggression:
We observed a considerable amount of competition for the cliff cavities in June and July, and attributed this to the upcoming nesting season in October. A few of the holes were measured by Dr. Charlie Munn and Lorgio Hirose, EcoBolivia's foreman. They were determined to be as large as 2 metres deep by 6 inches wide by 10 inches tall. Some had tunnels that branched off from them, making them ideal sites for macaws to protect themselves and their eggs/chicks from predators or foul weather.
Pairs of macaws that had already established themselves in holes aggressively defended their territory against invading pairs. When I arrived at Caquiahuara, nine pairs of Red-and-Green macaws were regularly roosting in particular holes. When a new pair would try to land in a cavity belonging to an existing pair, the resident pair would usually very aggressively chase the new pair away without any fighting involved. On several occasions, however, I witnessed birds tumbling in the air from cliff holes while grappling beak to beak after an invading pair attempted entry into an already established residence. Similar aggression and competition amongst pairs of macaws that were not settled in the cliff also existed over vacant holes. By the time we departed from Caquiahuara, twelve pairs of Red-and-Green macaws were defending cavities.
Some interesting observations were made regarding defense of these sites. One pair in particular, which we named Pair#1, defended three holes very successfully for an entire month and a half. Laurel and I departed from Caquiahuara for one week to study another site, and when we returned, two of Pair#1's holes were being occupied. In other words, there was a new pair in the cliff that must have successfully fought Pair#1 for one of their homes. On one occasion, we observed this new pair aggressively confront Pair#1. The new pair flew directly at Pair#1 who were sitting within their cavity, landed on the ledge at the entrance of the cavity, and faced Pair#1 with their wings spread. They stood there as such for about 20 seconds until Pair#1 finally lunged at them. All four birds beak fought until the new pair gave up and flew away.
Another interesting pair was Pair#4 who acted as the "guards" of the cliff. Not only would they defend their own cliff site, they protected the cavities of three other pairs of Red-and-Green macaws in their absence. This behaviour is contrary to past observations that Red-and-Green macaws are individualistic or pair-oriented, rather than group-oriented.
Antipredator Behaviour and Alarm Calling
Macaws faced with imminent danger from predators give out very loud alarm calls which alert other macaws in the vicinity. Alarm calls from one bird most frequently results in large numbers of birds flying away from the danger or around in circles, while calling loudly. Several macaws randomly flying in circles may confuse the predator who as a result, cannot focus on one particular bird as a potential item of prey. This reduces the predator's chances of capturing a bird.
We observed this antipredator behaviour in response to bat falcons, humans, and a helicopter. In fact, when a Red-and-Green macaw alarm-called, not only would other Red-and-Greens respond, but the severe macaws and white-eyed parakeets also responded by calling loudly and flying away. Furthermore, severe macaw alarm calls usually caused most of the white-eyed parakeets in the near vicinity to respond, but only occasionally caused a few Red-and-Green macaws to flee.
In this population of macaws, there was a single juvenile from last year's nesting season. The juvenile was the same size as its parents, but had more vivid facial markings. During the day, it socialized with its parents and followed them around, flying or perching with them. As the family of three perched together, the juvenile would continuously bob its head, beg for food, and solicit preens when it was perfectly capable of feeding or preening itself. While relentlessly begging, it often irritated a parent to the point that the parent would bite it, lunge at it, or chase it away. These interactions frequently resulted in the juvenile flying away from the tree, circling back, and landing on the same branch as before, but slightly farther away from the parent.
The juvenile also foraged or explored on its own, clumsily walking along branches, and chewing or sampling twigs and leaves. It often roosted alone on cliff ledges or branches that overhang the cliff. This most commonly resulted in the juvenile being chased away by adult macaws, usually in pairs.
Every evening when its parents returned to their cliff cavity, the juvenile would follow them until they entered, and then double back to fly behind the cliff where it would spend the night, most likely on its own. This pattern of behaviour was repeated night after night, ie. the juvenile never entered its parents' territory with them.
Local School Children and Environmental Education
Once a month, EcoBolivia brings local school children to Caquiahuara for three-day trips. The children learn about the plants and animals of the jungle, rainforest ecology, biodiversity, and the importance of conserving the rainforests. Laurel and I helped teach one group of 15 twelve-year-olds about macaw behaviour and how to birdwatch using telescopes and binoculars, things that they had never seen before. The children generally demonstrated a positive attitude towards the learning experience, and most, if not all, of them did not want to leave Caquiahuara when the time came to return to their communities.
Future Goals at Caquiahuara
Second and third macaw chicks of clutches have a significantly higher mortality rate than first-hatched chicks because the parents tend to pay more attention and give more food to the first chick. Because of this, EcoBolivia intends to rescue poor-doing second and third chicks, and raise them until they are ready to be released into the wild, and forage on their own. This approach to parrot conservation has been shown to be quite successful by the team at the Tambopata Research Centre in Perù.
One of EcoBolivia's goals for Caquiahuara is to bring in tourists interested in seeing the macaws in the wild, not to mention the spectacular plant life and other wildlife in the area. The research station can comfortably hold eighteen people at one time, hence successful ecotourism at this site is on its way and very promising.
Laurel and I spent three days studying the series of much larger macaw cliffs in Charque, which is also located within the proposed borders of the Alto-Madidi National Park. Due to funding difficulties, Charque had been left unprotected for one year. Last year, EcoBolivia determined the population size of the Red-and-Green macaws to be 24 in all. However, when we were there, we counted 7 pairs, ie. 14 birds. There also seemed to be a decline in the number of Blue-and-Yellow macaws (Ara ararauna) which do not use the cliffs, but build nests in nearby palm groves. Although these apparent declines are not conclusive due to our short stay in Charque, protection of this area is extremely important due to other evidence of destruction we observed. There was mass removal of trees and plants, wide trails where none existed before, chopped up trees allowed to sit and rot, destroyed and mucked-up streams that were once clear, and littered abandoned campsites. Once funding improves, EcoBolivia plans to build a station at Charque, and hire more local people to protect the land and all its life from these invaders. Hopefully the populations of the different macaw species will rebuild themselves under better and safer conditions.
The Blue-throated Macaws in the Savannahs of Bolivia
Another project that Charlie introduced me to focussed on the Blue-throated macaws (Ara glaucogularis) in the savannahs of Bolivia. This species is endemic to Bolivia, and is extremely endangered -- there may be as little as 29 pairs left in the wild. The first field studies by the Wildlife Conservation Society began in 1992 after it was determined that several Blue-throated macaws inhabited small forest islands (1-4 ha) located in the savannahs of the Department of Beni in Bolivia. At present, very little has been published about this species in the wild to adequately assess its conservation status, however conservationists assume that it may very well be in immediate danger of extinction.
Previous observations of these birds in the wild have indicated that competition exists between this species and a similar looking species: the Blue-and-Yellow macaws (Ara ararauna). A. ararauna are slightly larger in size, have black throats as opposed to blue throats, and have calls that are much lower in frequency. Furthermore, they are not nearly as endangered as the Blue-throated macaws.
During nesting season, both species lay their eggs within cavities of palm trees located within the forest islands. A. ararauna seem to outcompete A. glaucogularis for these nest sites of which there is a shortage. To help deal with this inadequate number of nesting sites, a native Bolivian man (who up until 1984 used to trap and trade large macaws for a living) created artificial nest sites by excavating cavities in eight dead palm trees last year. This man guided Laurel and me to the site in August, and we determined that one of the artificial cavities was being used and further excavated -- not by Blue-and-Yellow macaws, but by a pair of Blue-throated macaws. In fact, we observed a couple of incidents of aggressive/competitive behaviour between two pairs of Blue-throated macaws for this particular cavity. None of the Blue-and-Yellow macaws appeared interested in the cavities, hence we did not witness competitive behaviour between the two species. It would be quite interesting to observe what happens to the rest of these potential nest sites when nesting season comes along.
The location of this study and the name of our guide are kept confidential to protect the Blue-throated macaws that are possibly on the verge of extinction from smugglers involved in the pet black market.
I would like to extend my thanks to Charlie Munn for giving me the opportunity to participate in the various projects I worked on in Bolivia, and Rosamarìa Ruiz for allowing me to study the macaws at Caquiahuara, and be a part of the team at EcoBolivia. I would also like to thank Rosamarìa and the EcoBolivia team, Charlie, Wayne Davey, Mike Pearson, Margaret Mostert, and Laurel Neufeld for their guidance and moral support. Warm thanks go to the Bolivian landowners, our nameless expert guide, and the local people who were exceptionally hospitable and invaluable to our Blue-throated macaw research. Furthermore, I thank the Canadian World Parrot Trust, the Golden Triangle Parrot Club, the Parrot Association of Canada, the Canadian Parrot Association, the Lafeber Company, the University of Guelph, the Ottawa Parrot Club, the Avian Preservation Foundation, and the Vancouver Island Cage Bird Society for their generous contributions that helped fund my work.
If you would like more informaton on any of the projects I participated in, please contact me at the Ontario Veterinary College, OVC Box 482, University of Guelph, Guelph, Ontario, N1G 2W1, or e-mail me at firstname.lastname@example.org. If you are interested in helping EcoBolivia with its various projects (via volunteer work or financial contribution) or writing to the Bolivian government to help speed up the process of establishing the proposed Alto-Madidi National Park, you can directly contact Rosamarìa Ruiz at Casilla 8505, La Paz, Bolivia or fax her at 011-5912-325-776. For more information on the Blue-throated macaws and how you can help, contact Charles A. Munn, Senior Conservation Zoologist, Wildlife Conservation Society, Bronx, NY 10460.
Catherine Soos is a third-year veterinary student at the Ontario Veterinary College of the University of Guelph. She graduated at Concordia University (Montreal) in 1992 with an Honours BSc in Biology in which she concentrated on behaviour and ecology. Soos has four years of research experience, two of which she spent studying animal behaviour and behavioural ecology. Furthermore, she is co-author of two scientific papers recently published in Animal Behaviour (1995) and Behavioral Ecology and Sociobiology (1994). Soos is quite interested in rainforest ecosystems and conservation, and is actively involved in studying wild parrot behaviour and aiding parrot conservation. She intends to combine these interests with her career as an avian/exotic animal veterinarian.