Greater Vasa Parrots Grind Shell Calcium With Date Pits and Pebbles

Summary: Captive greater vasa parrots grind shell calcium with date pits and pebbles as shared tools, according to a study published Dec. 16 in Biology Letters.

greater vasa parrot (Coracopsis vasa) in native homeland, Madagascar: AEM, CC BY SA 3.0 Unported, via Wikimedia Commons

Captive greater vasa parrots (Coracopsis vasa) in an aviary at UK’s Lincolnshire Wildlife Park use and share date pits and pebbles as tools to grind cockleshells into calcium as a dietary supplement, according to a study published Wednesday, Dec. 16, 2015, in Biology Letters.

Eight months of observations and filming throughout the day, between 8 a.m. and 7 p.m., March to October 2013, document first-ever nonhuman use of tools for grinding. Film and observation records confirm beak-to-beak transfers of scraping tools as numbering among the few reported instances of nonhuman direct tool sharing.

The grinding technique makes use of cockle shells and small pebbles retrieved from the aviary’s floor covering of cockleshells, pebbles, soil and wood chips. Five out of 10 greater vasa parrots in the aviary are observed positioning pebbles in their beak to grind cockleshells into calcium powder. When dates are featured on the parrots’ menu, they repurpose date pits as shell grinders.

The study’s team of University of St. Andrews and University of York psychology researchers find spikes in shell grinding occur just before the breeding season, from March to mid-April. Sufficient calcium levels are critical for successful eggshell formation.

Lead author Megan L. Lambert, a PhD student in the University of York’s Psychology Department, explains the significance of calcium supplementation: “Unlike mammals, birds cannot efficiently store calcium in the skeleton and so may still require an extra boost during the breeding season to assist with the formation of their eggshells, which are made almost entirely of calcium.”

Prior to the breeding season, males display a greater interest in shell scraping than females show. The puzzling observation possibly may be explained by transfer of calcium through the parrots’ practice of regurgitative feeding of females by males prior to mating.

The researchers do not know the how or why for novel tool use by the greater vasa parrots in the Lincolnshire Wildlife Park’s aviary.

Megan Lambert notes: “The use of tools by nonhuman animals remains an exceedingly rare phenomenon. These observations provide new insights into the tool-using capabilities of parrots and give rise to further questions as to why this species uses tools.”

Greater vasa parrots are native to the Indian Ocean island nations of the Comoros and Madagascar. Is novel tool-using an innate or learned behavior? Is tool-using practiced by both captive and native populations?

Megan Lambert notes the importance of ongoing research of greater vasa parrots: “Tool use could reflect an innate predisposition in the parrots, or it could be the result of individual trial and error learning or some form of social learning. Whether these birds also use tools in the wild remains to be explored, but ultimately these observations highlight the greater vasa parrot as a species of interest for further studies of physical cognition.”

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photo by Frank Wouters: Lincolnshire Wildlife Park, via Facebook Dec. 16, 2015

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

greater vasa parrot (Coracopsis vasa) in native homeland, Madagascar: AEM, CC BY SA 3.0 Unported, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Coracopsis_vasa_-Madagascar-8.jpg

photo by Frank Wouters: Lincolnshire Wildlife Park, via Facebook Dec. 16, 2015, @ https://www.facebook.com/permalink.php?story_fbid=932813933422065&id=257906397579492

For further information:

Angenent, Saskia. "New evidence of tool use discovered in parrots." University of York > News and events > News > 2015 news > Research. Dec. 15, 2015.
Available @ https://www.york.ac.uk/news-and-events/news/2015/research/tool-use-parrots/

Lambert, Megan L.; Amanda M. Seed; and Katie E. Slocombe. "A novel form of spontaneous tool use displayed by several captive greater vasa parrots (Coracopsis vasa)." Biology Letters, vol. 11, issue 12 (Dec. 01, 2015). Published Dec. 16, 2015. DOI: 10.1098/rsbl.2015.0861
Available @ http://rsbl.royalsocietypublishing.org/content/11/12/20150861

Lincolnshire Wildlife Park. "Our parrots make the headlines once again. This time in Nat Geo." Facebook. Dec. 16, 2015.
Available @ https://www.facebook.com/permalink.php?story_fbid=932813933422065&id=257906397579492

New Scientist. "Parrots use pebble tools to grind up calcium supplements." YouTube. Dec. 15, 2015.
Available @ http://www.youtube.com/watch?v=drTY2FZNkq0

New Scientist‏ @newscientist. "Parrots spotted using pebbles to grind up their own mineral supplements." Twitter. Dec. 15, 2015.
Available @ https://twitter.com/newscientist/status/676915965892943876

Scalise, Joseph. "Parrots use tools to create nutritional supplements, study reports." Science Recorder. Dec. 16, 2015.
Available @ http://www.sciencerecorder.com/news/2015/12/16/parrots-use-tools-create-nutritional-supplements-study-reports/

Viegas, Jen. "Parrots Make Their Own Vitamins." Seeker. Dec. 15, 2015.
Available @ http://news.discovery.com/animals/parrots-make-their-own-vitamins-151215.htm

Yong, Ed. "Tool-Using Parrots Use Pebbles to Grind Seashells." National Geographic > Science & Innovation > Not Exactly Rocket Science. Dec. 15, 2015.
Available @ https://www.nationalgeographic.com/science/phenomena/2015/12/15/tool-using-parrots-use-pebbles-to-grind-seashells/