Wild and captive Blue-throated Macaws are genetically distinct

Captive Blue-Throated Macaws

Captive Blue-Throated Macaws, The seemingly endless lowland savannas of the Llanuras de Moxos in north-east Bolivia are the only home of the rare and elegant Blue-throated Macaw.

With an area of 213,654 km2 these savannas are immense, and their seasonal flooding complicates access for half of the year. Furthermore, Blue-throated Macaws are currently found only in part of the savannas, distributed in northern and southern populations. Thus, it is understandable that even finding them can consume a disproportionately high amount of effort and resources, and at least partly explains why the discovery of the species’ breeding grounds was not made until 1992.

A post-discovery evaluation showed the species to be in fragile condition, and it was designated as Critically Endangered on the IUCN Red List of Threatened Species. It was severely threatened in the past by exploitation for the international cage-bird trade. Breeding sites are on private cattle ranches, where burning, tree clearing and grazing have reduced the number of suitable nest trees and inhibited Motacú Palm regeneration. Hunting to provide feathers for indigenous headdresses probably has had an impact in some areas, recruitment to the breeding population is slow and disease also represents a significant threat. At present the total number of mature individuals in the wild is thought to be no more than 250.

Preventing Its Extinction- Captive Blue-Throated Macaws

To prevent its extinction and help bring about its recovery, from 1995 the Loro Parque Fundación has been the principal supporter of Blue-throated Macaw conservation activities, to date having contributed US$1,945,000 to save it. Measures have included installing a project base of operations, the creation of a Species Recovery Plan recognised by the responsible authorities in Bolivia, defining the current geographical occurrence and regularly monitoring the presence and numbers at known locations. Research has provided key information about its behaviour, ecology, reproduction and natural diet. An intensive nestbox programme is in place, activities to manage an 11,000-ha nature reserve have been supported, and agreements have been made with landowners to protect more habitat. Markets in the main cities have been monitored to deter trafficking. To create institutional and public support, extensive awareness and education initiatives are undertaken. Furthermore, hunting pressure has been mitigated by the involving local communities in the creation of artificial feathers to make the ceremonial headdresses.

These on-the-ground efforts have been paralleled by activities elsewhere. In 1984 the very first macaw chick to be hatched in a controlled environment was at Loro Parque, which continues its involvement as a member of the Blue-throated Macaw European Endangered Species Programme (EEP). The Loro Parque Fundación breeds the species in its international breeding centre and in February 2020 achieved the successful hatching of its 400th chick. The result is that there are sizeable Blue-throated Macaw populations under human care.

Most wild Blue-throated Macaws were exported from Bolivia in the 1970s and early 1980s, and conservation efforts raise interesting questions about how much genetic diversity there is between wild and captive populations. 

A team led by Professor Tim Wright at New Mexico State University is providing answers to these questions by genetic analysis of 66 wild individuals from Bolivia and 54 captive individuals from the USA, Canada and Bolivia. The results show that wild Bolivian populations are genetically distinct from captive populations.

This genetic analysis will help inform ongoing conservation efforts, not least the positive effects that could come from increased gene flow between the wild and captive populations. For example, nowadays the technology and expertise exist to be able to transfer fertile eggs from captivity to wild foster nests and vice versa. Even with the need for disease testing, this would appear to be a safer and less expensive option than trying to augment the wild population with the release of captive-bred individuals, where the disease risk is major and demands the most rigorous screening.

Parrots regularly carry pathogens, which can remain cryptic. Some parrot diseases incubate for many months and some healthy birds are life-long carriers which can transmit pathogens. Given that parrots are typically sociable, disease can spread rapidly. Wild Blue-throated Macaws may be reasonably spaced-out during the breeding season, but regular non-breeding (dry) season flocks in excess of 100 individuals show that they will concentrate in one place from a much more extensive area. Of particular difficulty to screen effectively is avian bornavirus (ABV), known to cause proventricular dilatation disease (PDD), otherwise known as macaw wasting disease, the first recorded cases of which coincided with importations of wild macaws from Bolivia.

In a survey of wild parrots in Brazil, 47% of 86 individuals were found to have signs of ABV infection, PDD, or both. This implies that ABV is likely also to reside in wild birds in Bolivia, and therefore it might be assumed that transmission from captive individuals is less of a worry. However, this fails to take into account that there are now eight described parrot bornaviruses, and these different strains may cause disease differently. If a population has one strain and can cope with it, exposing it to another strain may carry a high risk of causing harm.

Thus, any putative release programme must have a level of testing sophistication which, for lack of knowledge, resources or commitment, is not always available. For example, in 2013 six Blue-throated Macaws captive-bred in the UK were sent to Bolivia, ostensibly as part of a release programme. Records show that disease tests were performed and that these were the typical tests for three distinct pathogens requested by governmental veterinarians to prevent reportable avian diseases to be spread from country to country, principally related to protection of the poultry industry. More than two years later, at the request of the Bolivian Government, expert advice from Europe urged testing for 10 distinct pathogens, including the likes of the highly contagious circovirus (causing Psittacine Beak and Feather Disease), and ABV. It is not known if the recommended testing has yet been accomplished.

Much has already been achieved to prevent the extinction of Blue-throated Macaw, with the genetic analysis a valuable recent addition. Prudent use of this information will continue to protect this icon of Bolivia’s biodiversity.