Indian pond heron

Indian pond heron
In non-breeding plumage (Sri Lanka)
Breeding plumage in (Kolkata, India)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Family: Ardeidae
Genus: Ardeola
Species: A. grayii
Binomial name
Ardeola grayii
(Sykes, 1832)
Synonyms

Ardeola leucoptera

The Indian pond heron or paddybird (Ardeola grayii) is a small heron. It is of Old World origins, breeding in southern Iran and east to Pakistan, India, Burma, Bangladesh and Sri Lanka. They are widespread and common but can be easily missed when they stalk prey at the edge of small water-bodies or even when they roost close to human habitations. They are however distinctive when they take off with bright white wings flashing in contrast to the cryptic streaked olive and brown colours of the body. Their camouflage is so excellent that they can be approached closely before they take to flight, a behaviour which has resulted in folk names and beliefs that the birds are short-sighted or blind.[2][3]

Description

Usually hunched, they appear short necked
Pond Heron sitting on floating weeds in a lake in Bangalore

They appear stocky with a short neck, short thick bill and buff-brown back. In summer, adults have long neck feathers. Its appearance is transformed from their dull colours when they take to flight, when the white of the wings makes them very prominent. It is very similar to the squacco heron, Ardeola ralloides, but is darker-backed. To the east of its range, it is replaced by the Chinese pond heron, Ardeola bacchus.

During the breeding season, there are records of individuals with red legs. The numbers do not suggest that this is a normal change for adults during the breeding season and some have suggested the possibility of it being genetic variants.[4][5][6][7]

Erythristic plumage has been noted.[8] The race phillipsi has been suggested for the populations found in the Maldives, however this is not always recognized.[9] It forms a superspecies with the closely related Chinese pond heron, Javan pond heron and the Madagascar pond heron.

They are usually silent but may give a harsh croak when flushed or near their nests.[9]

This bird was first described by Colonel W. H. Sykes in 1832 and given its scientific name in honour of John Edward Gray. Karyology studies indicate that pond herons have 68 chromosomes (2N).[10]

Behaviour and ecology

When flushed the contrasting white wings flash into view

They are very common in India, and are usually solitary foragers but numbers of them may sometimes feed in close proximity during the dry seasons[11] when small wetlands have a high concentration of prey. They are semi-colonial breeders. They may also forage at garbage heaps. During dry seasons, they sometimes take to foraging on well watered lawns or even dry grassland. When foraging, they allow close approach and flush only at close range. They sometimes form communal roosts, often in avenue trees over busy urban areas.[12]

Food and feeding

Indian Pond Heron with prey(fish) at Sakherbazar, Kolkata
Indian Pond Heron with fish as prey .

The Indian pond heron's feeding habitat is marshy wetlands. They usually feed at the edge of ponds but make extensive use of floating vegetation such as water hyacinth to access deeper water. They may also on occasion swim on water or fish from the air and land in deeper waters.[13][14][15][16] They have also been observed to fly and capture fishes leaping out of water.[17] [18] Sometimes, they fly low over water to drive frogs and fishes towards the shore before settling along the shoreline.[19]

The primary food of these birds includes crustaceans, aquatic insects, fishes, tadpoles and sometimes leeches (Herpobdelloides sp.).[20] Outside wetlands, these herons feed on insects (including crickets, dragonflies[21] and bees[22]), fish (Barilius noted as important in a study in Chandigarh) and amphibians.[23]

Breeding

Pair at nest in Kolkata, West Bengal, India
Indian pond heron with bright red legs in breeding season

The breeding season begins with the onset of the monsoons. They nest in small colonies, often with other wading birds, usually on platforms of sticks in trees or shrubs. Most nests are built at a height of about 9 to 10 m in large leafy trees. The nest material is collected by the male while the female builds the nest. Three to five eggs are laid.[24] The eggs hatch asynchronously, taking 18 to 24 days to hatch. Both parents feed the young.[25] Fish are the main diet fed to young.[11] Nest sites that are not disturbed may be reused year after year.[26]

Movements

Nocturnal movements of pond herons have been noted along the coast near Chennai.[27]

Mortality factors

They have few predators but injured birds may be taken by birds of prey.[28]

An arbovirus "Balagodu", trematodes[29] and several other parasites have been isolated from the species.[30][31][32][33][34] Antibodies to Japanese encephalitis and West Nile virus has been detected in pond herons and cattle egrets from southern India.[35] Traces of heavy metals acquired from feeding in polluted waters may be particularly concentrated in the tail feathers.[36]

In culture

Large numbers in a drying pond
Pond Heron at Narayanganj, Bangladesh

The habit of standing still and flushing only at the last moment has led to widespread folk beliefs that they are semi-blind and their name in many languages includes such suggestions. In Sri Lanka the bird is called kana koka which translates as "half-blind heron" in the Sinhala language.[2] The phrase "bagla bhagat" has been used to describe a "wolf in sheep's clothing" or a heron appearing like a meditating saint.[37]

During the height of the plume trade, feathers were collected from the "paddy bird" and exported to Britain.[38]

References

  1. ↑ BirdLife International (2012). "Ardeola grayii". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. 1 2 Anonymous (1998). "Vernacular Names of the Birds of the Indian Subcontinent" (PDF). Buceros 3 (1): 53–109.
  3. ↑ Yule, Henry, Sir. Hobson-Jobson (1903). A glossary of colloquial Anglo-Indian words and phrases, and of kindred terms, etymological, historical, geographical and discursive. New ed. edited by William Crooke, B.A. J. Murray, London.
  4. ↑ Gopisundar, K. S. (2004). "Abundance and seasonality of Indian Pond Herons Ardeola grayii with red legs in Uttar Pradesh, India" (PDF). Forktail 20.
  5. ↑ Abdulali, H. and Alexander, H. G. (1952). "Ardeidae with red legs". Ibis 94 (2): 363. doi:10.1111/j.1474-919X.1952.tb01829.x.
  6. ↑ Wesley, H. D. (1993). "Genetics of the red tarsi and feet in the Pond Heron". Newsletter for Birdwatchers 33 (4): 73.
  7. ↑ Sundar, Gopi KS. "Distribution and extent of Pond Herons Ardeola grayii with red legs in India" (PDF). Indian Birds 1 (5): 108–115.
  8. ↑ Parasharya,BM (1983). "An erythristic pond heron". Pavo 21 (1&2): 107–108.
  9. 1 2 Rasmussen, PC & JC Anderton (2005). Birds of South Asia:The Ripley Guide. Smithsonian Institution & Lynx Edicions.
  10. ↑ M. K. Mohanty & S. P. Bhunya (1990). "Karyological studies in four species of ardeid birds (Ardeldae, Ciconiiformes)". Genetica 81 (3): 211–214. doi:10.1007/BF00360867.
  11. 1 2 Begum, S. (2003). "Colonial nesting behavior in Indian Pond Heron (Ardeola grayii grayii) of Bangladesh" (PDF). Zoos' Print Journal 18 (6): 1113–1116. doi:10.11609/jott.zpj.18.6.1113-6.
  12. ↑ Gadgil, Madhav & Salim Ali (1975). "Communal roosting habits of Indian birds" (PDF). J. Bombay Nat. Hist. Soc. 72 (3): 716–727.
  13. ↑ Chandra-Bose,DA (1969). "The Paddybird, Ardeola grayii (Sykes) floating on water". Pavo 7 (1&2): 74–75.
  14. ↑ Neelakantan,KK (1986). "Pond heron afloat". Newsletter for Birdwatchers 26 (5–6): 11–13.
  15. ↑ Krishna, MB (1978). "Pond Herons". Newsletter for Birdwatchers 18 (10): 10.
  16. ↑ Muir,GBF (1916). "Paddy-birds Ardeola grayii fishing". J. Bombay Nat. Hist. Soc. 24 (2): 366–367.
  17. ↑ Grimwood,IM; Brocklehurst,MJC (1984). "Unusual feeding behaviour in the Paddy Bird or Indian Pond Heron Ardeola grayii". J. Bombay Nat. Hist. Soc. 81 (3): 696–697.
  18. ↑ Sivasubramanian,C (1988). "Aerial feeding by Median Egret (Egretta intermedia), Little Egret (Egretta garzetta) and Pond Heron (Ardeola grayii)". J. Bombay Nat. Hist. Soc. 85 (3): 611–612.
  19. ↑ Kirkpatrick, K. M. (1953). "Feeding habit of the Indian Pond Heron (Ardeola grayii)". J. Bombay Nat. Hist. Soc. 51 (2): 507.
  20. ↑ Mathew,DN; Narendran,TC; Zacharias,VJ (1978). "A comparative study of the feeding habits of certain species of Indian birds affecting agriculture". J. Bombay Nat. Hist. Soc. 75 (4): 1178–1197.
  21. ↑ Santharam,V. (2003). "Indian pond-herons Ardeola grayii feeding on dragonflies". Journal of Bombay Natural History Society 100 (1): 108.
  22. ↑ Prasad,JN; Hemanth,J (1992). "Pond Heron Ardeola grayii (Sykes) feeding on bees". J. Bombay Nat. Hist. Soc. 89 (2): 246.
  23. ↑ Sodhi, NS (1986). "Feeding ecology of Indian pond heron and its comparison with that of little egret". Pavo 24 (1&2): 97–112.
  24. ↑ Pandey, Deep Narayan (1991). "Nesting of the Pond Heron Ardeola grayii (Sykes) on Eucalyptus trees". J. Bombay Nat. Hist. Soc. 88 (2): 281.
  25. ↑ Yesmin, R., Rahman, K. & Haque, N. (2001). "The breeding biology of the Pond Heron (Ardeola grayii Sykes) in captivity". Tigerpaper 28 (1): 15–18.
  26. ↑ Ali, S. & S. D. Ripley (1978). Handbook of the birds of India and Pakistan 1 (2 ed.). New Delhi: Oxford University Press. pp. 63–64.
  27. ↑ Santharam,V (1987). "The Pond Heron - its local movements". Newsletter for Birdwatchers 27 (9&10): 4–6.
  28. ↑ Navarro,A (1962). "Pale Harrier taking a Pond Heron". J. Bombay Nat. Hist. Soc. 59 (2): 653.
  29. ↑ Umadevi K & R. Madhavi (2000). "Observations on the morphology and life-cycle of Procerovum varium (Onji & Nishio, 1916) (Trematoda: Heterophyidae)". Systematic Parasitology 46 (3): 215–225. doi:10.1023/A:1006398205390. PMID 10845654.
  30. ↑ Pavri K, Sheikh BH, Singh KR, Rajagopalan PK, Casals J (1969). "Balagodu virus, a new arbovirus isolated from Ardeola grayii (Sykes) in Mysore State, South India". Indian J Med Res. 57 (4): 758–64. PMID 4979767.
  31. ↑ Pavri KM, Rajagopalan PK, Arnstein P (1968). "Isolation of Ornithosis bedsoniae from paddy birds, Ardeola grayii (Sykes), in Mysore State India". Indian J. Med. Res. 56 (11): 1592–4. PMID 5715959.
  32. ↑ Sahay S; Sahay U; Verma DK (1990). "On a new trematode of the genus Psilorchis (Psilostomidae Looss, 1900) from pond heron Ardeola grayii". Indian journal of parasitology 14 (2): 203–205.
  33. ↑ Madhavi, R;Narasimha Rao, N;Rukmini, C (1989). "The life history of Echinochasmus bagulai Verma 1935 (Trematoda, Echinostomatidae)". Acta Parasitologica Polonica 34 (3): 259–265.
  34. ↑ Deshmukh PG (1971). "On the male of Avioserpens multipapillosa Singh, 1949 from Ardeola grayii". Rivista di Parassitologia 32 (2): 101–3. PMID 5166875.
  35. ↑ Paramasivan, R.; A.C. Mishra & D.T. Mourya (2003). "West Nile virus: the Indian scenario" (PDF). Indian J Med Res 118: 101–108. PMID 14700342.
  36. ↑ Muralidharan, S., Jayakumar, R., Vishnu, G (2004). "Heavy metals in feathers of six species of birds in the district Nilgiris, India". Bulletin of Environmental Contamination and Toxicology 73 (2): 285–291. doi:10.1007/s00128-004-0425-x. PMID 15386041.
  37. ↑ Pahwa, Munshi Thakardass (1919). The modern Hindustani scholar of the Pucca munshi. Baptist Mission Press, Calcutta.
  38. ↑ Watt, George (1908). The Commercial Products of India. London: John Murray. p. 139.

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