From the field: The Hyacinth Macaw Project: Piaui, Brazil

Abstract

T he Hyacinth Macaw, Anodorhynchus hyacinthinus, was at one time widely distributed through Brazil, Bolivia, and Paraguay. However, a more recent survey has estimated their total numbers to be between 2500 to 5000, in three distinct populations. These populations are located in the rainforests of Para, Brazil, in the seasonally dry, rocky valleys of northeastern Brazil (Tocantins, Piaui, Maranhao, and Bahia), and the Pantanal wetland of Brazil, Bolivia, and Paraguay (Guedes et al, 1995). At this time the most studied population had been that one located in the Pantanal, leaving these other two to be further examined. The

Hyacinth Macaw is currently considered rare to endangered, and at a definite risk of becoming extinct if the causal factors continue to operate. To this day trapping and international trade, hunting, agriculture, logging, and hydroelectric projects considerably insult their survival (Guedes, 1993).

The objectives of the Hyacinth Macaw Project 1996/1997 field season were to assess the area of southern Piaui, located in northeastern Brazil, and the population of Hyacinth Macaws located there for future studies. This is a completely separate population from that one located in the Pantanal wetlands with different nesting habits. These birds nest in cavities located in the large cliffs of this region. We were to collect information concerning their diet, and study the physical condition of chicks. In addition, we intended to collect preliminary data concerning nest cavity temperature and relative humidity, nest dimensions, and nest distribution in the cliffs.

During the study I worked closely with three parabiologists. This team was headed by Mr. Lourival Lima, an ex-trapper in the area. These people now act as wardens, patrolling and protecting this area and have prevented trapping of the macaws during the last two years. Working with them was particularly useful as they have extensive knowledge concerning scouting

nests and climbing cliffs, as well as a thorough knowledge of Hyacinth Macaw chicks. This work would have been very difficult, to impossible without their expertise. Mr. Lima and his colleagues have an extreme interest and pride in sharing their knowledge of the Hyacinth Macaw, as well as of the other birds in the area.

To evaluate the previous trapping situation and the current population of Hyacinth Macaws in the area, several ex-trappers were interviewed separately and repeatedly. Consistent reports of trapping an average of 80-100 Hyacinth Macaws per year were obtained. This included chicks and reproducing adults. Approximately 70% of the nests were exploited, the remaining 30% were reported as inaccessible to humans (L. Lima personal communication, 1996). The current total numbers were difficult to assess accurately as I worked in a small area as compared to the reported habitat for these birds. However, they are assumed to be severely depleted due to decades of trapping. In addition to Hyacinth Macaws, several other psittacine species were trapped in the area. These included Green-Winged Macaws Ara chloroptera, Blue and Gold Macaws Ara ararauna, and previously, Spix's Macaws Cyanopsitta spixii.

Several criteria had to be met during evaluation of the diet of the Hyacinth

Macaw. Each fruit had to be found in the nest cavity, dropped just outside the opening, or be seen eaten by one of these birds. In addition, several extrappers in the area were questioned separately and repeatedly concerning their diet. Only consistent reports were interpreted as truth. Due to the fact that during the nesting season these birds are considerably spread out, it was very difficult to actually visualize a Hyacinth Macaw eating each fruit. Therefore, this information should be interpreted with this in mind.

Hyacinth Macaws were found to consume several fruits which were abundant in the area (Table 1.) These included chute, pia caba, sapucaia, tucun, and buruti. At this time only the Brazilian names for these fruits are known. I am currently working with several botanists and palm specialists to ascertain the scientific and common English names of these fruits. Different portions of these fruits were consumed and they are available in peak numbers at different times of the year. In addition to these fruits, the Hyacinth Macaws were reported to consume clay found in the cliffs and nest cavities. Other psittacine species have been found to consume clay on a regular basis as well. The current leading explanation for this is detoxification of other items ingested and cytoprotection of the gastrointestinal tract Q. Gilardi, unpublished data).