Jacucaca: Ecology, Survival, and Conservation in Brazil’s Caatinga

Among the rocky outcrops and thorny vegetation of Brazil's Caatinga lives one of the region's most emblematic and threatened birds: the White-browed Guan (Penelope jacucaca), popularly known in Brazil as jacucaca. Endemic to this uniquely Brazilian biome and currently classified as Vulnerable, this large cracid plays a fundamental ecological role as a disperser of native plant seeds in one of South America's most seasonal environments.

White-browed Guan (Penelope jacucaca) at the feeding areas, Pedra dos Ventos Hotel: Quixadá, Ceará.

A master’s dissertation developed at the Federal University of Ceará provides valuable insights into how this species survives under extreme climatic conditions and how its feeding ecology supports key ecological processes in the Caatinga.

The Caatinga: A Harsh and Unique Brazilian Biome

The Caatinga is the only biome entirely restricted to Brazil, covering nearly 10% of the national territory. It is characterized by a mosaic of seasonally dry tropical forests, shrublands and open woodlands adapted to high temperatures, intense solar radiation and extremely irregular rainfall. Annual precipitation is low (less than 800 millimeters) and unpredictable, concentrated in a short rainy season that may last 3 to 5 months, followed by prolonged periods of drought.

This pronounced seasonality shapes every ecological process in the Caatinga. Plant communities are dominated by deciduous species, many of which lose their leaves during the dry season to reduce water loss. Fruiting and flowering events are strongly synchronized with rainfall, creating brief windows of high resource availability. For wildlife, survival depends on behavioral flexibility, mobility and the ability to exploit a wide range of resources.

Despite its harsh conditions, the Caatinga hosts a remarkable level of endemism. Many plant and animal species, including the Jacucaca, are found nowhere else. However, centuries of human use, combined with weak legal protection, have made the Caatinga one of the most threatened and least protected biomes in Brazil.

Caatinga during the rainy season at Logradouro Farm - Quixadá, Ceará.

Cracids and Their role as Seed Dispersers

Cracids (Cracidae), including guans, curassows and chachalacas, are among the largest frugivorous birds in the Neotropics. Their body size, gape width and digestive physiology allow them to consume large fruits and seeds that are inaccessible to smaller birds. As a result, they play a unique and irreplaceable role in seed dispersal, particularly for plant species with large or hard-coated seeds.

Unlike many smaller frugivores, cracids often swallow fruits whole and defecate the seeds intact, maintaining high seed viability after gut passage. Their daily movements, which may include long foraging routes between feeding, roosting and resting sites, promote seed dispersal across considerable distances. This process enhances gene flow among plant populations and contributes to forest regeneration and structural complexity.

Intact seed found in fecal samples.

In seasonal environments such as the Caatinga, the role of cracids becomes even more critical. During the rainy season, when fruit availability peaks, species like the White-browed Guan act as primary dispersers for a subset of native trees, shrubs and cacti. The loss of these birds can lead to cascading ecological effects, including reduced recruitment of large-seeded plants and long-term changes in vegetation composition.

Studies across Neotropical forests consistently show that the decline or local extinction of cracids results in functional defaunation. Even when forests remain structurally intact, the absence of large seed dispersers alters ecological processes in subtle but profound ways, ultimately reducing ecosystem resilience.

The Jacucaca and Human Pressure

For centuries, the Jacucaca has been closely linked to human life in the semi-arid Northeast. As a large-bodied bird, it represents an important source of animal protein for rural communities, and hunting has long been part of traditional subsistence practices across the Caatinga. In some areas, the species is also valued culturally, featuring in local knowledge, stories and seasonal hunting traditions.

However, this close relationship has come at a cost. Studies compiled in long-term monitoring efforts show that this Guan is among the most heavily hunted birds in the region. Because it is relatively large, conspicuous, and often occurs near fruiting trees or water sources, it becomes an easy target for hunters, especially during the dry season when resources are scarce.

How This Study was Carried Out

The research discussed here was carried out in protected areas of the Caatinga in northeastern Brazil, Quixadá – Ceará, at Pedra dos Ventos Hotel and Logradouro Farm, focusing on natural populations of the Jacucaca. Fieldwork was conducted across both dry and rainy seasons to capture seasonal variation in diet and resource use.

Diet was investigated through systematic collection and analysis of fecal samples. Each sample was carefully examined to identify seeds, fruit remains, animal, vegetable and mineral material, allowing determination of the relative importance of different food items throughout the year.

By comparing sites with and without supplemental feeding during the dry season, the study also evaluated how artificial food sources influenced dietary composition and ecological behavior of the species.

Map of the studied areas: Pedra dos Ventos Hotel (Top) and Logradouro Farm (Bottom). The pink lines represent the trails covered during the research.

How Diet Changes Throughout the Year

The Caatinga is defined by extremes. Long dry months drastically reduce the availability of fruits, followed by a short rainy season when the landscape transforms and food becomes abundant. For a large, ground-dwelling frugivore like the Jucucaca, adapting to these changes is a matter of survival.

During the rainy season, the guan’s diet was dominated almost entirely by fruits and other plant material. Seeds of native species, especially Juazeiro (Ziziphus joazeiro) and cacti (Cactaceae) were frequently found intact in fecal samples, confirming the bird’s efficiency as a seed disperser when resources are plentiful. 

 Intact Seeds found in fecal samples.

The dry season, however, tells a different story. With scarce fruits, guans broadened their diet considerably, consuming invertebrates, small vertebrates, mollusks, and other non-plant items. Corn was only identified in fecal samples from the dry season at Pedra dos Ventos Hotel. This opportunistic behavior highlights the species' resilience and ecological plasticity in this challenging environment.

Items consumed by the Jacucaca during the dry season.

Do Feeders Help or Harm?

One of the most interesting aspects of the study was the evaluation of a corn feeder used during the dry and rainy seasons at Pedra dos Ventos Hotel. While corn appeared frequently in samples collected during the dry period, it virtually disappeared from the diet once the rainy season began, even though the feeder remained active.

This suggests that supplemental feeding did not replace natural food sources when fruits were available. Instead, it likely helped maintain a higher number of individuals in a protected area during the most critical months of the dry season, without negatively affecting seed dispersal processes and the ecological role of this species.

Heat map (Kernel) showing the distribution and concentration of samples during the dry (red and yellow) and rainy (blue and green) seasons at the Pedra dos Ventos Hotel. The pink spot represents the feeder and the triangles represent fecal samples.

Why Protecting the Guan Means Protecting the Caatinga

Hunting pressure and habitat loss remain the main threats. In many parts of its range, the species is heavily hunted and local populations have declined sharply. Protecting safe refuges, encouraging private conservation initiatives and understanding how the species uses the landscape throughout the year are all essential steps toward its long-term survival.

More than a study about diet, this research is a reminder that conserving birds like the Jacucaca means safeguarding entire ecological processes. In the Caatinga, where resilience is everything, the quiet work of a seed-dispersing bird can shape the future of the habitat.

For birders visiting northeastern Brazil, encountering this bird is always special, not just because it is endemic and threatened, but because it represents the deep and often unseen connections between birds, plants and people in the Brazilian Caatinga.

The Jacucaca is just one of many endemic species that depend on the fragile dry forests of northeastern Brazil. Often overlooked, the Caatinga holds a unique community of birds found nowhere else in the world, each shaped by extreme seasonality and long periods of drought. For birders interested in experiencing this biome firsthand, these Caatinga species (including the Jacucaca) can be observed during any of our Northeast Tours, where conservation, local knowledge and responsible tourism go hand in hand. If this sparked your curiosity, you can check whether there are still spaces available on one of our Northeast Popular Tours.

References:

AB'SABER, Aziz Nacib. O domínio morfoclimático semi-árido das caatingas brasileiras. Geomorfologia, São Paulo, n. 43, p. 1-39, 1974.

CRUZ, Lucas Barros de Castro. DIETA E MANEJO ALIMENTAR DE PENELOPE JACUCACA (GALLIFORMES: CRACIDAE) DE VIDA LIVRE E SEU POTENCIAL COMO DISPERSOR DE SEMENTES DA CAATINGA. 2022. 73 f. Dissertação (Doutorado) - Curso de Programa de Pós-Graduação em Sistemática, Uso e Conservação da Biodiversidade, Universidade Federal do Ceará, Fortaleza, 2022.

BEZERRA, Dandara Monalisa Mariz et al. Habitat use, density, and conservation status of the white-browed guan (Penelope jacucaca Spix, 1825). Journal For Nature Conservation, [S.l.], n. 51, p. 1-10, ago. 2019.

DEL HOYO, J. Guans, Chachalacas, Curassows (Cracidae). In: DEL HOYO, J. et al. (eds.). Handbook of the Birds of the World Alive. Barcelona: Lynx Edicions, 2019. Disponível em: https://www.hbw.com/node/52217. Acesso em: 17 mai. 2019.

GALETTI, M. et al. Functional extinction of birds drives rapid evolutionary changes in seed size. Science, [S.l.], v. 340, n. 6136, p. 1086-1090, 2013. Disponível em: http://dx.doi.org/10.1126/science.1233774.

VALTUILLE, Tarcilla et al. Conservação do jacu do nordeste: um estudo na caatinga brasileira. Florianópolis: Samec, 2017.