What’s that Call in the Evening?

Oct 07, 2015 No Comments by

Common Name: Black-crowned Night Heron Scientific Name: *Nycticorax nycticorax* Red List Category and Criteria: Least Concern Population Trend: Decreasing The resident Black-crowned Night Heron thrives globally on the shores of salt and freshwater marshes. They have a distinctive raspy “Wok” call (Kaufman 2015), and are crepuscular (Vencatesan et al. 2014), or most active at dusk and dawn. Adult birds have a gray belly, bluish shoulder, and black crowned head while young birds are streaked brown for camouflage. In Southern India, these birds nest between December and February. Males choose nest sites and display by ruffling feathers, stepping back and forth from foot to foot, bowing, stretching their necks, and hissing to attract mates (Snow and Perrins 1998). Males provide twigs as females construct nests in tree canopies or on dry ground near water (Snow and Perrins 1998). Black-crowned Night Herons are often found in nest colonies with other species like herons, egrets, or ibis (Kaufman 2015). Females will lay about four eggs that will hatch after a month (Kaufman 2015). Black-crowned Night Herons prefer shallow wetlands with fresh, brackish, or saline waters with aquatic vegetation and surrounding trees to roost and nest (del Hoyo *et al.* 1992, Sashikumar *et al. *2011). Rather than standing still and waiting for prey to approach, they actively stalk prey when they hunt by wading and spearing fish with their beaks (Ali 2012, Kaufman 2015). Daytime hunting is normal if food is plentiful during breeding season (Davis 1993), and the opportunistic predators will eat fish, frogs, aquatic invertebrates, snakes, turtles, lizards, insects, small rodents, and the eggs or chicks of other birds (del Hoy *et al*. 1992, Vencatesan *et al.* 2014). Black-crowned Night Herons return annually to the same roosts and are threatened by wetland drainage and habitat destruction (del Hoyo *et al*. 1992, Kushlan and Hancock 2005). The species’ higher level on the food chain puts it at higher risk of pollutant biomagnification. Pesticide residues like organophosphates and breakdown products of DDT (Kwon *et al*. 2004, Kaufman 2015) can greatly affect reproductive success. There are cases of increased levels of heavy metals in Korean birds that are known to travel to other parts of Asia (Kim 2007). Black-crowned Night Herons can migrate great distances, and poor health of an individual bird may not accurately reflect the health of the ecosystem or pollutants in the area where the individual is captured. Written by Calli Wise Sources: 1. Ali, S├ílim. 2012. *The Book of Indian Birds*. 13th Edition. Oxford University Press, New York. 2. Birding in India and Indian Subcontinent. < http://www.birding.in/> 3. BirdLife International 2012. *Nycticorax nycticorax*. The IUCN Red List of Threatened Species. Version 2015.2. . Downloaded on 11 August 2015 4. Daniels, RJR. (2015). *Birds of Pallikarnai Marsh, Chennai*. Newsletter for Birdwatchers, Volume 54 (issue 3). 5. Davis Jr, W.E. 1993. *Black-crowned Night-Heron (Nycticorax nycticorax), The Birds of North America Online*. Cornell Lab of Ornithology, Ithaca 6. del Hoyo, J.; Elliot, A.; Sargatal, J. 1992.*Handbook of the Birds of the World, vol. 1: Ostrich to Ducks*. Lynx Edicions, Barcelona, Spain. 7. IUCN Red List of Threatened Species. Version 2015.2. <*http://www.iucnredlist.org *> Accessed 11 Aug. 2015. 8. Kaufman, Kenn. 2015. Lives of North American Birds. National Audubon Society. 9. Kim, J; Koo, Tae-Hoe. 2007. *Heavy metal concentrations in diet and livers of Black-crowned Night Heron Nycticorax Nycticorax and Grey Heron Ardea cinerea chicks from Pyeongtaek, Korea*. Ecotoxicology 16: 411-416. 10. Kushlan, J.A; Hancock, J.A. 2005. *The Herons*. Oxford University Press. Oxford. 11. Kwon, Y. K.; Wee, S. H.; Kim, J. H. 2004. Pesticide Poisoning Events in Wild Birds in Korea from 1998 to 2002. *Journal of Wildlife Diseases* 40(4): 737-740. 12. Sashikumar, C; J, Praveen; Palot, MJ, Nameer, PO. 2011. *Birds of Kerala: Status and Distribution*. DC Books, Kottayam. 13. Vencatesan, J; Daniels, RJR; Jayaseelan, JS; Karthic, NM. 2014*. Comprehensive Management Plan for Pallikaranai Marsh, Technical Report submitted to the Conservation Authority for Pallikaranai Marsh, Tamilnadu Forest Department*. 264pp. 14.

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