The rufous-necked hornbill (Aceros nipalensis) is a very large hornbill belonging to the family Bucerotidae.
The rufous-necked hornbill species are distributed in India, Nepal, Bhutan, China, Myanmar, Laos, Thailand and Vietnam. These hornbill species are listed as "Vulnerable" by the IUCN. These hornbills are monotypic species.
Rufous-necked hornbill - Overview
- Scientific name: Aceros nipalensis
- Species author: (Hodgson, 1829)
- Synonyms/Protonym: Buceros Nipalensis Hodgson, 1829
- Family: Bucerotidae › Bucerotiformes › Aves › Chordata › Animalia
- Vernacular names: English: Rufous-necked hornbill, Chinese: 棕颈犀鸟, French: Calao à cou roux, German: Nepalhornvogel, Spanish: Cálao del Nepal, Russian: Непальский калао, Japanese: ナナミゾサイチョウ
- Other names: Rufous necked Hornbill
- Distribution: India, Nepal, Bhutan, China, Myanmar, Laos, Thailand, Vietnam
- Diet and feeding habits: fruits, berries, figs
- IUCN status listing: Vulnerable (VU)
Appearance, physical description and identification
The rufous-necked hornbill (Aceros nipalensis) is a very large hornbill, measuring 90 to 100 cm in length.The male rufous-necked hornbill is slightly larger and weighs 2500 grams whereas the female weighs around 2200 grams. These species are sexually dimorphic, the male has reddish brown head, neck and underparts. The upperparts in male are black and the black wing has white-tipped outer primaries.
The female rufous-necked hornbill has black head, neck and underparts. The juveniles have plumage similar to males but their bills lack dark ridges. The tail in adult is long and the basal half is black and the distal half is white.
The bill is pale yellow in adult and has a row of vertical dark ridges on the upper mandible. The casque is almost absent. There is red gular skin. The irises are brownish red and orbital skin is pale blue. Their call is a loud barking "kok..kok" sound.
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| Rufous-necked hornbill - Aceros nipalensis |
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| Rufous-necked hornbill - Aceros nipalensis |
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| Rufous-necked hornbill - Aceros nipalensis |
Origin, geographical range and distribution
The rufous-necked hornbill species are distributed in India, Nepal, Bhutan, China (southern Yunnan and south-east Tibet), Myanmar, Laos, Thailand and Vietnam. It is probably extinct in Nepal and almost extinct in Vietnam.In India, these rufous-necked hornbill species are distributed in the states of northern West Bengal, Assam, Arunachal Pradesh, Meghalaya, Nagaland, Manipur and Mizoram.
The Important Bird and Biodiversity Areas (IBA) of the rufous-necked hornbill species in China are Yarlung Zangbo Daxiagu Nature Reserve, Xishuangbanna, Nabanhe Nature Reserve and Lhakhang. The IBA in Vietnam are Pu Mat and Che Tao.
The IBA of the rufous-necked hornbill species in Bhutan are Toorsa Strict Nature Reserve, Thrumsing La National Park, Sarpang-Gelephu foothills, Samtse, Royal Manas National Park, Phipsoo Wildlife Sanctuary, Kori La, Neoli Wildlife Sanctuary, Kamji, Jigme Singye Wangchuk National Park and Samdrup Jongkhar.
Some of the IBA of these hornbill species in India are Namdapha National Park, Papum Reserve Forest, Pakke Tiger Reserve, Nameri National Park, Manas National Park, Sonai-Rupai Wildlife Sanctuary, Buxa Tiger Reserve, Mount Zanibu, Mahananda Wildlife Sanctuary and Magu Thingbu.
The IBA of the rufous-necked hornbill species in Myanmar are Hkakaborazi, Ngwe Taung, Hponkanrazi, Nat-yekan, Hukaung Valley and Kyauk Pan Taung. The IBA in Thailand are Huai Kha Khaeng, Umphang, Thung Yai - Naresuan and Mae Wong.
Ecosystem and habitat
These rufous-necked hornbill species have high forest dependency. These species occur in altitudes from 150 to 2200 meters.The natural ecosystems of these hornbill species include tropical and subtropical moist montane forests, tropical and subtropical moist lowland forests, dense evergreen forests, broadleaved forests, deciduous foothill forests and dry woodlands.
Diet and feeding behavior
The diet of these rufous-necked hornbill species is mostly fruits. Berries, drupes, fruits of Lauraceae spp., Moraceae spp., Meliaceae spp. and Annonaceae spp. are their primary food.Reproduction and breeding habits
The breeding season of these rufous-necked hornbill species in northeast India is from March to June. These hornbills are monogamous species. They nest in natural holes and hollows in old, tall, wide-girthed trees.The rufous-necked hornbill pair may use the same nesting site in consecutive breeding seasons. After entering the hollow, the female seals the hole with its droppings, mud and fruit pulp.
A small aperture is left for the male to transfer food to the mother and the chicks. The typical clutch contains one or two pale white eggs.
Migration and movement patterns
These rufous-necked hornbill species are non-migratory resident birds. Movements to lower altitudes during winter had been reported.Post breeding, the juveniles may disperse and establish in new locations within the range. They may make local movements for feeding and breeding within their range.
Conservation and survival
The global population size of the rufous-necked hornbill (Aceros nipalensis) is estimated to be around 1500 to 7000 individual birds. The overall population trend of these species is considered to be decreasing. Throughout its range it is reported to be very rare. The generation length is 19 years. Their distribution size is about 1,300,000 sq.km.The rufous-necked hornbill (Aceros nipalensis) has approached the thresholds for being Vulnerable, under the range size criterion, under the population trend criterion and also under the population size criterion.
The cutting of old fruiting and nesting trees, deforestation, habitat fragmentation, hunting and trapping for pet trade are the main threats that may endanger the survival of these hornbill species.
IUCN and CITES status
The IUCN (International Union for Conservation of Nature) has categorized and evaluated the species and has listed it as "Vulnerable". The CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) status is ‘Evaluated’ for the rufous-necked hornbill (Aceros nipalensis) and listed in Appendix II.| Taxonomy and scientific classification of Aceros nipalensis | |
|---|---|
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Bucerotiformes |
| Family: | Bucerotidae |
| Subfamily: | - |
| Genus: | Aceros |
| Species: | A. nipalensis |
| Binomial name: | Aceros nipalensis |
| IUCN status listing: |
 Vulnerable |
1.Image source: https://commons.wikimedia.org/wiki/File:Rufous_Necked_Hornbill.jpg (cropped)
Image author: Ujjal Ghosh | License: CC BY-SA 3.0
2.Image source: https://commons.wikimedia.org/wiki/File:Rufous-necked_hornbill_1.jpg (cropped)
Image author: Rohit Naniwadekar | License: CC BY-SA 3.0
3.Image source: https://en.wikipedia.org/wiki/File:Rufous-necked_Hornbill.jpg (cropped)
Image author: Kalyanvarma | License: CC BY-SA 3.0
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