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Black-shouldered Kite regurgitation or vomiting?

on 14th May 2015

On 21st April 2015, Melinda Chan sent in two images of a juvenile Black-shouldered Kite (Elanus caeruleus) photographed by Chan Yoke Meng (above, below). The kite was on a high perch spewing a sticky substance. There were two other juvenile kites on the same tree. They had a flock of Red-breasted Parakeets (Psittacula alexandri) as well as a single Hahn’s Macaw for company.

Was the kite regurgitating or vomiting?

According to the literature, regurgitation is part of the normal behavior of birds. When adults feed chicks or indulge in courtship feeding, food is forced out of the mouth, oesophagus or crop LINK. With the casting of a pellet, the compacted indigestible parts of the prey are forced out of the gizzard in the form of a pellet LINK. Regurgitation is also seen when a bird swallows a fruit and later ejects the seed LINK.

Vomiting on the other hand is the expulsion of the contents of the crop, proventriculus, ventriculus or intestine. Vomiting can be regurgitation in self defense against predators, as seen in Black-naped Terns (Sterna sumatrana) retaliating with vomit when an adult Grey Heron (Ardea cinerea) approached the colony LINK.

Southern Giant Petrel similarly “produces a stomach oil made up of wax esters and triglycerides that is stored in the procentriculus can be used as a projectile vomited on predators … The oil mats the feathers of birds together and destroys their waterproofing abilities, so soiled birds may die from chilling and/or drowning…” LINK.

Can this be a liquid projectile spewed by the Black-shouldered Kite? But then there were no attacker. Maybe it can be due to illness?

According to Dato’ Dr Amar-Singh HSS birds can vomit from illness but it is not possible to ascertain the cause here.

“Regurgitation in birds can be due to illness (known as vomiting), defence, casting pellets and feeding behavior,” wrote Amar, who provides a number of links below:

1. Vultures using defensive vomiting (acid) LINK.

2. Even gull chicks can spray oil in defence LINK.

3. Defensive regurgitation LINK 1 and LINK 2.

4. Nice video HERE

According to aviculturist Lee Chiu San, “… parrots [and other birds] do throw up when they are sick, or when something that they have eaten does not agree with them.”

So the jury is still out in the case of this Black-shouldered Kite. It may well by illness but other causes may be possible. Anyone with an answer, please share with us.

Chan Yoke Meng, Melinda Chan, Dato’ Dr Amar-Singh HSS & Lee Chiu San
Singapore
May 2015

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

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