Tracking of Lear’s Macaws – Defines home ranges but also Underscores threats

David Waugh
Correspondent, Loro Parque Fundación

A home range is the geographic area that an animal regularly uses for its normal activities, such as foraging for food, finding shelter and breeding but which, unlike a territory, it may not actively defend. The area encompasses the daily movements and interactions of an individual animal, or a group of animals, providing resources necessary for survival and reproduction. The size of a home range can vary according to a variety of influences including the abundance and quality of food, the time of year, an individual’s sex, and the species of course. Until very recently there were no reliable estimates of home ranges of Lear’s Macaws (Anodorhynchus leari), but research by Paschotto et al. (2025) involving the GPS-tracking of individual juveniles has now provided solid information about the ranges and the ecology of this species in the landscape. The research also underscores some of the threats confronting this species.

The Lear’s Macaw has a very small geographical distribution in the northern limit of the state of Bahia in Brazil, being native to the tropical dry forest and scrub of the arid Caatinga biome. The macaws nest and roost in cavities in cliffs within the region (although more recently some macaws have been found roosting in trees), and feed within the native Caatinga vegetation as well as in agricultural areas, especially in relation to the presence of licuri palms (Syagrus coronata), the fruits and nuts of which are a key food resource.

The Lear’s Macaw is threatened by continuing degradation of its habitat and food supply, by occasional farmer persecution for foraging on maize crops, by illegal removal of individuals from the wild for trade and by more recently introduced infrastructure. Despite these ongoing threats, the situation of the Lear’s Macaw has been steadily improving.

A wild population of the species, estimated to comprise about 60 individuals, was first found only in 1978. In 2001 this population was estimated at 246 individuals, with 632 in 2006, 1,200 in 2016, 1,694 in 2018 until the most recent census in September 2024 of 2,548
individuals. Part of the increase is due to improved census protocols, but there has been a genuine rise because of the conservation measures adopted over time, and in 2009 the IUCN Red List status of the Lear’s Macaw was downlisted from ‘Critically Endangered’ to ‘Endangered’.

Beginning in 1998 the Loro Parque Fundación provided input to the relevant Brazilian government agencies for the conservation of the Lear’s Macaw, and in 2006 started to finance actions in Bahía for its in situ conservation, as well as receiving two pairs on loan from the Brazilian Government to establish an ex situ safety-net population. These actions are both
within the framework of Brazil’s National Action Plan for the species, and the Loro Parque Fundación has achieved successful annual breeding of Lear’s Macaws as well as its ongoing support to conserve the wild population.

From the two traditional cliff sites, the species has been colonising additional sites, even though Brazilian biologist Dr Erica Pacífico has discovered that only about 20 per cent of individuals are reproductively active in any given breeding season. 

In 1995, a roosting site holding 22 Lear’s Macaws was located in the region of the protected areas of the Environmental Protection Area and National Park of Boqueirão da Onça, 230 km west of the two traditional sites of Canudos Biological Station and the Ecological Station of Raso da Catarina. By 2019 this sub-population was functionally extinct, with only two non-breeding adult macaws. However, since then a long-term reintroduction and monitoring project, led by Dr Pacífico of the Lear’s Macaw Research and Conservation Group (GPCAL), has been releasing rescued, confiscated and captive-bred macaws. The Loro Parque Fundación has been contributing funds to this project, and some of the captive-bred Lear’s Macaws which it has repatriated to Brazil for release have subsequently bred successfully in the wild.

The GPS-tracking research by Paschotto et al. (2025) identified 3,038 feeding, 1,228 resting and 2,923 roosting locations, and mapped their spatial distribution in the Boqueirão da Onça and Raso da Catarina regions. The resting sites were located very close to the feeding areas, with a median distance of only 19.8 meters to the nearest feeding site. Additionally, 2.5 per cent of resting areas overlapped with feeding locations. Feeding sites were closer than resting sites to the roosting sites, but both feeding and resting sites were located as far as 36 km from the nearest roost. The macaws spent about 8 hours daily in foraging sites and by comparison the time spent in resting sites was almost two times shorter, with a median value of 4.2 h. The macaws roosted about 12 h per night (ranging from 9 to 14 h), leaving the roosts and initiating exploration of the foraging sites around 05:30 – 06:30 am.

During the winter, macaws tended to arrive later and leave both the feeding and resting sites earlier. Both the feeding and resting activities occurred throughout the day, lasting until late afternoon. Habitats visited by the macaws were characterised with variables representing man-altered features, land cover and topography. Of the land types identified as used by the macaws, 100 per cent had some indication of human activities. Pastures comprised the most frequented land type, these often having licuri palms within them, or helping to form the pasture boundaries. 

More than half of feeding and resting sites were concentrated within areas directly related to agricultural activity, these being pasture and mosaic of uses (the category employed where it was not possible to distinguish between pasture and agriculture), with about 50 per cent located in non-natural pastural land. The natural land types of forest and savanna accounted for about 25 per cent of feeding and resting sites. 

Roosting sites showed the opposite tendency, with the native vegetation categories accounting for 50 per cent of locations, while 25 per cent of locations were within agricultural use land. About 20-25 per cent of the feeding, resting and roosting sites were in the land category of ‘other non-vegetated areas’, being clearly human-modified areas such as infrastructure, urban expansion or mining.

The research provided first time accurate estimates of home ranges, at the same time revealing substantial variation, with an average of 850.15 km² and range of 1.24 to 8,549.48 km². Home ranges expanded significantly during the dry season to an average of 1,097.06 km², representing a 2.14-fold increase from the wet season. The research also found that season and site (i.e. site where each macaw was born, or released and tagged, and from where the individual performs daily movements to forage) primarily influenced home range size, while vegetation productivity and rainfall had limited effect.

In terms of highlighting threats to Lear’s Macaws, Paschotto et al. (2025) were also able to show the distribution of distances of macaws from power lines, the average distances while feeding and resting being very similar and both much closer than the average distance of roosting sites from the power lines.

A study by Biasotto et al (2022), compiling and describing 31 electrocution events in the Caatinga, has indicated that electrocution may be an important threat to Lear’s Macaw. Electrocution occurs when a macaw simultaneously touches two-phase conductors or one conductor and a grounded device on a pole or pylon and therefore is expected to be especially common in local distribution lines due to the short distances among the electrified elements.

Unfortunately, power lines and pylons offer attractive perching sites for Lears’ Macaws, frequently bordering roads where licuri palmsmight also be present. Biasotto et al. (2025) have recently explored this threat in more detail, including mapping the spatial and temporal patterns of electrocutions in the Raso de Catarina region, to be able to recommend some immediate prioritised, cost-effective mitigation measures for decreasing the threat. Across the region the researchers mapped the probability of occurrence of licuri palms, from low to high abundance, and mapped the density of power lines, again from low to high. The locations of 63 fatality events of electrocuted Lear’s Macaws were then overlain on the same map.

The combined information allowed the researchers to present a framework to identify high-risk electrocution areas, and therefore to prioritise mitigation efforts. For Lear’s Macaws the electrocution risk was unevenly distributed across the study area, with the central and southern portions of the energy grid identified as priorities for mitigation. On a scale of electrocution risk from 0 (no risk) to 0.5 (maximum risk), the county of Euclides da Cunha had the highest risk value of 0.38, while the lowest risk county of Rodelas had a risk value of 0.01. Other high-risk counties were Canudos, Jeremoabo and Novo Triunfo. In terms of mitigation measures, the researchers also performed a cost– benefit analysis to determine the number of pylons that would need retrofitting to achieve specific reductions in electrocution events. The analysis revealed that retrofitting only 10 per cent of pylons (approximately 37,000) could reduce electrocution events by 80 per cent.

These recent studies highlight the need for continuous monitoring to address threats posed to the Lear’s Macaw by environmental changes and human activity.