A Comparative Analysis of the Crested Serpent Eagle (Spilornis cheela malayensis) and Abbott's Crested Serpent Eagle (Spilornis cheela abbotti)

*Heri Tarmizi

Crested serpent eagle Malayensis
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Created serpent eagle abboti 
image source Google 

Introduction:

The Crested Serpent Eagle (Spilornis cheela) is a majestic raptor found across South and Southeast Asia. Within this species, two distinct subspecies, Spilornis cheela malayensis and Spilornis cheela abbotti, exhibit notable differences in morphology, coloration, and habitat preferences. This essay aims to explore and compare these two subspecies, shedding light on their unique characteristics.

Morphological Differences:

One of the primary distinctions between Spilornis cheela malayensis and Spilornis cheela abbotti lies in their size. Generally, Spilornis cheela malayensis tends to be slightly larger, with a wingspan ranging from 130 to 160 centimeters, compared to the smaller wingspan of Spilornis cheela abbotti, typically measuring between 120 to 150 centimeters (1). Additionally, subtle variations in plumage coloration exist between the two subspecies.

Coloration:

Spilornis cheela malayensis typically exhibits darker plumage compared to Spilornis cheela abbotti. The former often displays a darker brown or rufous coloration on its upperparts, while the latter may have lighter brown or chestnut hues. Moreover, differences in facial markings, such as the presence of a distinct crest and facial disc, contribute to the unique appearance of each subspecies.

Habitat Preferences:

Both subspecies of Crested Serpent Eagles exhibit preferences for forested habitats, but they may inhabit slightly different ecological niches within these environments. Spilornis cheela malayensis is commonly found in lowland forests, including primary and secondary forests, as well as wooded areas near rivers or marshes (2). In contrast, Spilornis cheela abbotti tends to inhabit higher elevation forests, including montane and submontane forests, often ranging from 500 to 2000 meters above sea level (3). These distinct habitat preferences may reflect adaptations to specific ecological conditions and prey availability in their respective ranges.

Behavior and Feeding Ecology:

While both subspecies primarily feed on reptiles, including snakes, lizards, and occasionally small mammals and birds, variations in behavior and hunting techniques may exist between Spilornis cheela malayensis and Spilornis cheela abbotti. Observations suggest that Spilornis cheela malayensis may exhibit a preference for hunting in more open areas within forested habitats, utilizing perches to scan the surroundings for prey (4). On the other hand, Spilornis cheela abbotti may demonstrate a greater affinity for dense forest understories, employing stealthy tactics to ambush prey within the thick vegetation (5). These behavioral differences may be influenced by the availability of suitable hunting grounds and the presence of competitors or predators within their respective habitats.

Conclusion:

In conclusion, the Crested Serpent Eagle comprises two distinct subspecies, Spilornis cheela malayensis and Spilornis cheela abbotti, each characterized by unique morphological features, coloration, and habitat preferences. While Spilornis cheela malayensis tends to inhabit lowland forests and displays darker plumage, Spilornis cheela abbotti is typically found in higher elevation forests and may exhibit lighter coloration. Further research is warranted to explore additional aspects of their biology, ecology, and evolutionary history.

References:

1. Rasmussen, P. C., & Anderton, J. C. (2005). Birds of South Asia: The Ripley Guide. Smithsonian Institution & Lynx Edicions.

2. Kemp, A. C. (1995). The Hornbills: Bucerotiformes. Oxford University Press.

3. Lerner, H. R., & Mindell, D. P. (2005). Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA. Molecular Phylogenetics and Evolution, 37(2), 327-346.

4. Ferguson-Lees, J., & Christie, D. A. (2001). Raptors of the World. Houghton Mifflin Harcourt.

5. Clark, W. S., & Schmitt, N. J. (2011). A field guide to the raptors of Europe, the Middle East, and North Africa. Oxford University Press.