Field and General Reports

Report from Palo Verde National Park
July 2004
Brian T. Smith

The Scarlet Macaws, Ara macao, of Palo Verde National Park with management recommendations

Introduction

The Scarlet Macaw, Ara macao, is a widely distributed psittacine from southern Mexico to Bolivia but has become largely scarce through much of its range especially Central America (Synder et al. 1999). Populations in Central America are of particular conservation interest because of the limited habitat left and low population numbers. It is believed that by 2010 only protected populations of macaws will remain in Central America (Synder et al. 1999). Anthropocentric activities are the principle cause for the massive reduction of macaw populations (Forshaw 1977, Juniper and Parr 1998). Extensive habitat destruction and poaching for the pet trade has depressed populations. In Costa Rica, a Central American nation, Ara macao were considered abundant in the early twentieth century but are now limited to a few protected regions (Forshaw 1977). Presently there are only three distinct subpopulations of Ara macao left in the country. Two are found in Corcovado National Park and Carrara Biological Reserve (Stiles and Skutch 1989, Vaughan et al. 2003). The third is in Palo Verde National Park and is highly endangered. The focus of this paper will be on a study completed on the remnant subpopulation in Palo Verde National Park.

Intensive land use changes from cattle grazing and agriculture have altered the composition of the Palo Verde's plant communities. Mature forests and trees are conspicuously absent from large tracts of the park, however faunal extinctions have been low (Stoner and Timm 2004). Cattle have degraded many habitats in the park but regeneration is present in the park's vast secondary growth. But, cattle still graze in the park as part of an unsuccessful control plan for cattail growth in the marshes (Stoner and Timm 2004). The historical misuse of the land has highly fragmented the macaw's habitat in dry forests. Since Ara macao utilize mature forests for foraging and nesting, forest degradation has greatly reduced available nest sites and food resources (Juniper and Parr 1998).

Deforestation in the park is not an imminent threat to the population but fire is always a potential problem. Crop fields are burned annually in the areas surrounding the park and have spread into the park. Extensive tracts of forest have been destroyed and which can greatly reduce macaw habitat (Barrantes and Sanchez 2004). Fortunately many regions in the park are regenerating.

To compound the issue Ara macao is a highly sought after species in the pet trade (Clubb 1992, Wright et al. 2001). The negative effects of poaching on pssitacines for the pet trade have been clearly illustrated by Wright et al. (2001). Nest poaching of juvenile Ara macao in Carrara Biological Reserve has been rampant in unprotected areas (Vaughan et al. 2003). The extent of poaching in Palo Verde National Park is not known but must be considered a threat.

Research recommendations

It is critical that studies be initiated to understand the available habitat within the park. The carrying capacity of the park needs to be estimated and possible reintroductions must reflect these findings. It is crucial to understand whether the young secondary forests of Palo Verde can maintain a viable population. Food availability and shelter from the heat change as cycles in the park change and how this affects the macaws, needs to be understood. Reintroduction without quantifiable knowledge about the population's ecology could prove detrimental to conservation measures (Synder et al. 1999). The importance of understanding the interaction between the macaws and the parks plant communities can not be understated.

Future studies should be initiated in the dry season (Dec-April). The forest is leafless for extended periods during the dry season and biting insects are less present. Conditions in the dry season will allow for easier visual identification of macaws. The dry season also corresponds with the breeding season therefore location of nests sites and active breeding pairs can be determined (Stiles and Skutch 1989). Expanding the sampling points should also be done, to include Catalina and up the Tempisque River.

Reports indicate that the macaws utilize Barra Honda National Park which is approximately 25kms to the south of Palo Verde National Park. Ulises Chavarria, a park ranger and parataxonmist, reports that the macaws fly to Barra Honda in periods of food shortage (pers com 2004). Flight lines to Barra Honda need to be determined and habitat along the corridor needs to be assessed. The preservation of this corridor and the population's foraging patterns might be critical for the population surviving extreme periods. Any possible reintroduction must be done while an extant population exists in Palo Verde to maintain flight lines and corridors out of the park. The historical foraging patterns must be considered crucial in maintaining future populations.

The role of commercial fruits plays a potentially important role in the macaw's diet. Virtually every report from locals in the area is of macaws eating in Mango trees, Mangifera indica. Negative remarks were not expressed; however, if population numbers do increase there is a likelihood of confrontation. From personal observation parrot densities (Amazona auropalliata and Amazona albifrons) were higher outside the park in fruit orchards. Therefore, commercial fruits might be vital for macaws to subsist in disturbed landscapes. The degradation of plant communities and the introduction of alien species have changed foraging dynamics. The extent in which macaws utilize these species needs to be determined and how farmers would react to increased feeding. However, it is encouraging that the species is a generalist and seems to adjust to available foods.

March 2006
Dale Forbes BSc, MSc

Tempisque Safari Release Programme

Nineteen macaws were originally released by Mr. Drew in Dec.2002 and Jan 2003, including Amigos 12 birds. Subsequently 6 more macaws have also been released.

Sightings of Released Macaws.

At least five macaws slept in the main farm area. One on the roof of the aviary, three in trees and one in a nestbox.

The following morning seven birds were seen in the immediate area. Four being banded and appeared to be Amigos birds. (numbers identified).

One pair appears to be very serious about nesting. The female is behaving as though she is sitting on eggs. There is also a second female in attendance at the nest and the male was seen allofeeding both females. Mr. Drew had two macaw chicks that he was hand raising in his house. These two chicks were apparently pulled from this same nest box when the chicks were 1 month old. He plans to release the chicks as soon as they are ready.

There is belief that there are other reintroduced macaws breeding in the mountains to the south of Palo Verde National Park and that one pair has, just this week, settled down to eggs in a large Ciba pentandra tree in Barro Honda National Park. It appears that the majority of the released macaws still survive in the area.

Released macaws were seen feeding on the seeds of various native tree species.

Observed food species eaten by the released macaws in Tempisque Safari.

Conclusion:

The macaws released in the program in Palo Verde appear to be fairing quite well and having good breeding success. Having birds actively breeding in the area appears to stimulate other pairs to form and attempt breeding. Unfortunately Mr. Drew has continued to hand feed birds at his farm and therefore three or four birds are super tame!

Whilst this detracts from a 'correct release program' it is interesting to note that the birds are well and surviving within the area of the National Parks and further study by Amigos will follow to provide further informative data.

February 2007
Jorge Hernandez
Benavides, Co-ordinator de Vida Silvestre, MINAE

In 2006 Mr. Drew opened his property to the public as a zoo. A report from Jorge Hernandez of Minae, has told us that during this year, there have been five youngsters produced by the Scarlet Macaws on this property. The birds are flying free on the property, but as mentioned by Dale Forbes previously, are an obvious "tourist attraction" and are situated in the midst of the zoo. Although the birds are free, they are being fed by zoo staff and therefore are not "surviving free" and sustaining themselves.

However, he also reports that the number of birds in Palo Verde National Parque have appeared to increase from approximately 12 to about 20, which would strongly indicate that some of the birds from our initial 12, are living in the park.

The youngsters that are bred in the zoo are also allowed to fly free, so we can but hope that some will "stray" into the realms of the park and live their lives being "wild" macaws.

Further reports this month from Jorge are that there have been 3 macaws noted, approximately 6-7 kilometers from the zoo in the direction of the National Park. Two of the birds had bird rings and one did not, and it was assumed that this one is a youngster. The three were noted in a Gallinazo tree in a creek near the Tempisque River.