The Silver-eared Mesia (Leiothrix argentauris rookmakeri) in Northwest Sumatra (Aceh)

 

*Heri tarmizi

Left a female, right a male
Photo by Peter Ericsson
Fraser's Hill, Malaysia, August 2006 
https://www.birdforum.net/opus/File:2712IMG_1758sm.jpg

The specific habitat preferences make this bird reliant on the presence of dense vegetation and forested areas for feeding, nesting, and shelter.

Introduction

The Silver-eared Mesia, Leiothrix argentauris, is a visually striking and melodically talented bird species belonging to the family Leiothrichidae. It is a resident species with a distribution that spans across Southeast Asia. One of its subspecies, Leiothrix argentauris rookmakeri, is found specifically in Northwest Sumatra (Aceh). This essay focuses on the habitat, behavior, conservation status, and challenges faced by L. a. rookmakeri in its natural forest habitats, referencing authoritative sources such as the Handbook of the Birds of the World, BirdLife International, and others.

 Habitat and Distribution

Leiothrix argentauris rookmakeri inhabits a variety of forested environments, typically found in bushes, undergrowth, and the lower Storey of forests. It thrives at the forest edge, in secondary growth, scrub, crop plantations, bamboo groves, and abandoned plantations. This subspecies is usually found at elevations between 600 and 2100 meters. The specific habitat preferences make this bird reliant on the presence of dense vegetation and forested areas for feeding, nesting, and shelter.

Behavior and Diet

The Silver-eared Mesia exhibits fascinating behavioral traits. It feeds on a diverse diet that includes insects (and their larvae), small fruits, berries, and seeds. This bird is particularly social outside the breeding season, often forming groups of 5 to 30 individuals. These groups frequently associate with other species in mixed-species flocks, moving through the underbrush but occasionally venturing up to 4-5 meters in the canopy.

Breeding in L. a. rookmakeri occurs from November to August, with the season starting in April in the northern part of its range. Both sexes participate in nest-building, creating a deep cup-shaped nest from dead bamboo and other leaves. The nest is typically placed in a bush, very close to the ground or up to 2 meters high. The species lays 2 to 5 eggs per clutch.

Conservation Status

The Silver-eared Mesia, including the subspecies L. a. rookmakeri, is currently listed as Least Concern by BirdLife International due to its extensive range, which covers approximately 5,770,000 square kilometers. Despite this broad distribution, the population trend is decreasing. However, the decline is not rapid enough to meet the criteria for a higher threat category, such as Vulnerable. Factors such as habitat loss, fragmentation, and degradation are contributing to the decline of suitable habitats for L. a. rookmakeri, making it increasingly difficult to find them in natural forests in Aceh.

Challenges in Natural Habitats

One of the significant challenges faced by L. a. rookmakeri is the degradation and loss of its natural forest habitats in Northwest Sumatra. The expansion of agricultural activities, deforestation, and the establishment of plantations (such as for crop and palm oil) are leading to significant habitat fragmentation. This fragmentation not only reduces the available habitat but also affects the bird's ability to move freely between different forest patches, essential for feeding and breeding.

Moreover, abandoned plantations and secondary growth areas, while providing some refuge, do not offer the same quality of habitat as primary forests. These areas often lack the dense undergrowth and rich biodiversity necessary to support the diverse diet and complex social behaviors of the Silver-eared Mesia.

Conservation Efforts and Recommendations

To conserve L. a. rookmakeri effectively, it is crucial to implement measures that address habitat preservation and restoration. Conservation strategies should include:

1. Protecting Primary Forests: Ensuring that remaining primary forests are protected from logging and conversion to agricultural land is vital. These forests provide the optimal habitat for L. a. rookmakeri and other forest-dependent species.

2. Restoring Degraded Habitats: Efforts should be made to restore degraded habitats, including reforestation with native plant species that can support the dietary and nesting needs of the Silver-eared Mesia  .

3. Creating Corridors: Establishing ecological corridors between fragmented forest patches can facilitate movement and genetic exchange between populations, enhancing the resilience of the species  

4. Community Engagement: Engaging local communities in conservation efforts through education and sustainable livelihood programs can reduce pressure on forest resources. Community-based monitoring and conservation initiatives can also play a significant role in protecting L. a. rookmakeri.

5. Research and Monitoring: Continued research is needed to monitor population trends, habitat usage, and the impacts of various threats. This data can inform adaptive management strategies and ensure that conservation efforts are effective.

Conclusion

The Silver-eared Mesia ( Leiothrix argentauris rookmakeri) in Northwest Sumatra faces several challenges due to habitat loss and fragmentation. While currently listed as Least Concern, the decreasing population trend indicates the need for proactive conservation measures. Protecting and restoring habitats, creating ecological corridors, and engaging local communities are essential steps in ensuring the survival of this vibrant and melodious bird species. By addressing these challenges, we can help preserve the rich biodiversity of Aceh's forests and secure a future for the Silver-eared Mesia.

References

1. del Hoyo, J., Elliott, A., & Christie, D.A. (Eds.). (2007). Handbook of the Birds of the World (Vol. 12). Barcelona: Lynx Edicions. ISBN 84-96553-42-6.

2. Clements, J.F. (2007). The Clements Checklist of Birds of the World (6th ed.). Ithaca: Cornell University Press. ISBN 9780801445019.

3. BirdLife International. (2024). Species factsheet: Silver-eared Mesia Leiothrix argentauris. Retrieved from [BirdLife International] https://datazone.birdlife.org/species/factsheet/silver-eared-mesia-leiothrix-argentauris

4. Rasmussen, P.C., & Anderton, J.C. (2005). Birds of South Asia: The Ripley Guide. Washington and Barcelona: Smithsonian Institute and Lynx Edicions. ISBN 84-87334-67-9.