PARROTS INTERNATIONAL
|
PARROTS INTERNATIONAL
|
|
|
Natural History of the Lears Macaw
By Samuel Williams, Lears Macaw observer and researcher
The Lear’s macaw is one of three large blue macaws from the genus Anodorhynchus. The two other species are the Glaucous macaw (A. glaucus), which for many years has been considered extinct, and the truly magnificent Hyacinth macaw (A. hyacinthinus). There is also a fourth blue macaw from a different genus; this is the smaller Spix macaw (Cyanopsitta spixi). Both the Lear’s and the Spix are critically endangered. Indeed the Spix is widely believed to be extinct in the wild and its fate depends on those who hold the last 60 or so individuals in captivity. The Lear’s, with its wild population of approximately 455 individuals (approximately 41 in captivity) is only in a marginally better situation. The Hyacinth however, has a larger wild population of approximately five thousand individuals and there are perhaps several thousand in captivity, consequently it is only considered vulnerable to extinction.
The Hyacinth macaw is held in high regard by parrot enthusiasts because of its size and beautiful shiny deep blue plumage. The Lear’s by comparison is often considered the smaller and less glamorous brother. At 75cm they are still large birds but the Hyacinth, which can grow to 1 meter is indeed the largest of all parrots. The plumage of the Lear’s generally appears slightly matt blue, however in good sunlight their feathers can appear glossy especially those on their wings and back. A faint tinge of green can be seen in their feathers and this is particularly apparent when they are wet after a rain shower. The Lear’s macaw’s most identifiable characteristic is their large rounded patch of yellow facial skin. The Hyacinths also have yellow facial skin but not to the same extent. Both these species also have other areas of yellow skin. These are: the orbital ring around the eye, on the cere, the sides of their tongue and also on their legs.
A significant though perhaps not widely appreciated difference between the Lear’s and Hyacinth is the size and shape of their wings. For their body size the Lear’s have long slender and pointy wings, which gives them the ability to perform dazzling aerobatic maneuvers. Such displays are performed regularly at the nest and roosting cliffs. The Hyacinths on the other hand plod along in a much less exciting fashion on their broader wings.
The Lear’s have a relatively limited distribution within Bahia state in the dry North east of Brazil. There are only two known nesting and roosting areas, and these are found in tall rock cliffs. Incredibly it may still be possible that there are as yet unknown groups of Lear’s in this region. Each day the macaws may fly several tens of kilometers to reach feeding areas. The habitat is a xerophytic (dry) thorny scrub known locally as the caatinga. Cacti are numerous here but more importantly it is here that the Licuri palm (Syagrus coronata) can be found.
An amazing 90% of the Lear’s macaw’s diet comes from the Licuri palm. There can therefore be no confusing the fact that the macaws are totally dependant on this palm and their conservation has to ensure the continuation of the Licuri into the future. Unfortunately however, as the human population in this region has expanded the number of small subsistence farms have increased, further reducing the available natural habitat. Perhaps an even greater concern is the grazing of cattle over large ranches. In many case land is cleared by fire and consequently many Licuri palms are lost. Efforts may be made to protect adult palms by the people clearing the land but this is only because their fruit bunches can be fed to cattle.
Another problem that now faces the Licuri palm population is the free range grazing of cattle over wide uncleared areas. This is thought to be having a negative impact on young palms. Between approximately 4 and 8 years of age the young Licuri develop a woody base and during this time they are particularly vulnerable to being stepped on by a passing cow, an injury from which they will probably not recover. An investigation into the levels of recruitment of young Licuri into the adult population really needs to be conducted to quantify this pressure. If indeed this is a serious threat, as is believed, there still may be time to develop simple cost effect management practices to protect the young palms.
The Lear’s macaws do not actually eat the Licuri palm fruit itself. This is efficiently stripped away to reveal a very hard nut the size of a large grape. They will then manipulate the nut and once happy they will split it open with a perfect cut. The white meat inside the nut is what these macaws are so dependant upon and it is quickly eaten before moving to the next one. Often a Lear’s will remove a cluster of 10-20 fruits from the raceme (bunch) that hangs from the palm. They may sit in the top of the palm and work their way through the cluster or they may choose to fly with their cluster to a nearby tree and eat them there. Breeding birds tend to swiftly work through several bunches before returning to their nests.
The Lear’s roost and breed in large cavities found high on the face of rock cliffs. Even before first light in the morning it is often possible to hear the muffled calls of awakening birds. As the light increases the birds leave the cliffs on their way to feeding areas. The breeding female will only leave the nest to join her partner on feeding trips once the chicks are able to cope without her providing warmth. At that time the pair may return several times to feed the chicks but as they develop the number of visits may be reduced to only two feeds. Throughout the breeding season the pair will roost inside the cavity each night. Lear’s chicks are believed to fledge at around 3 months of age and in their last weeks of confinement in the nest they become increasingly inquisitive and are often seen at the nest entrance. It is at this time that they are particularly vulnerable to poachers.
The most significant immediate conservation concern for the Lear’s macaw’s survival is that of the illegal trapping of birds for unscrupulous collectors worldwide. Amazingly some of these collectors are so confused they believe their actions benefit the conservation of these rare macaws because they are attempting to breed them in captivity. Clearly they are not taking into account the number of individuals that are killed in the process of trapping and smuggling, nor the genetic health of the decreasing wild population. Captive breeding of endangered species certainly has a role to play in conservation, however there are already approximately 41 Lear’s in captivity and are we certain those individuals and institutions are doing everything they can to learn and share their insights with each other for the benefit of Lear’s conservation? There can be no justification for removing more Lear’s from the tiny wild population at this time.
IBAMA, the Brazilian Natural Resource and Park Service, has been conducting quarterly censuring with the assistance of the BioBrazil and Biodiversitas Foundations. They are also developing research of the Lear’s natural history and nesting behaviour. This research will be used to develop optimal conservation strategies. When this actually happens then it could mark a turning point for this wonderful parrot species that presently faces extinction.
|
|
For purchase of high resolution photographs contact Parrots International Photos For donation to obtain your own DVDs go to Parrots International DVDs For Information contact info@parrotsinternational.org Or by mail at: Parrots International 15332 Antioch Ave. #417 Pacific Palisades, CA 90272
The "Digimarc Digital Watermarking" Web Button is a trademark of Digimarc Corporation, used with permission.
All proceeds from purchase of photos and donations for videos are donated to Parrots International conservation projects
|
