journal article Aug 03, 2017

Food availability and breeding season as predictors of geophagy in Amazonian parrots

Ibis Vol. 160 No. 1 pp. 112-129 · Wiley
View at Publisher Save 10.1111/ibi.12515
Abstract
Geophagy, the consumption of soil, is common in many species, but the drivers of geophagy are not well understood. The best‐studied example of avian geophagy is the parrots of the western Amazon Basin, but even here, there is debate over what drives the behaviour. There are two possible explanations: (1) extra nutritional demands of reproduction drive an increase in geophagy, which would predict that geophagy should be highest during the breeding season, and (2) consumption of naturally toxic plant foods increases the need for the toxin protection effects of soil, which would predict that geophagy should be highest when food availability is low and animals are forced to consume more toxic foods. We used long‐term data from lowland Amazonia to compare seasonal fluctuations in rainfall, food availability, parrot breeding and parrot geophagy, and conducted novel tests of these hypotheses. Our analyses of annual patterns suggested that seasonal changes in rainfall drive plant fruiting, the resulting food availability patterns drive the timing of parrot breeding, and breeding drives seasonal patterns of geophagy. Surprisingly, chicks of the largest psittacine species fledged as food supplies approach their annual lows, suggesting that future climatic changes that alter peaks in food availability could have unexpected impacts on the reproduction of large psittacines in this system. Our tests found no evidence to support the toxin‐protection hypothesis. Instead, we found that the peak of geophagy occurred during species’ breeding seasons, which strongly supports the supplemental nutrients hypothesis. Our findings join a growing body of biochemical, physiological, behavioural, ecological and biogeographical evidence suggesting that a need for sodium is driving soil consumption in this classic model system of avian geophagy.
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References
102
[3]
Alderton D. (2003)
[5]
Andreae M.O. "Precipitation chemistry in central Amazonia" J. Geophys. Res. Atm. (1990) 10.1029/jd095id10p16987
[6]
Angier N.2016.Parrots are a Lot more than ‘Pretty Bird’. New York Times 29 March.
[9]
Benkman C.W. (1992)
[10]
Best L.B. "Characterization of grit use by cornfield birds" Wilson Bull. (1991)
[17]
Brightsmith D.J. "Avian geophagy and soil characteristics in southeastern Peru" Biotropica (2004)
[18]
Brightsmith D.J. "Parrots consume sodium‐rich palms in the sodium‐deprived landscape of the Western Amazon Basin" Biotropica (2017) 10.1111/btp.12479
[25]
Robust Locally Weighted Regression and Smoothing Scatterplots

William S. Cleveland

Journal of the American Statistical Association 10.1080/01621459.1979.10481038
[26]
Locally Weighted Regression: An Approach to Regression Analysis by Local Fitting

William S. Cleveland, Susan J. Devlin

Journal of the American Statistical Association 10.1080/01621459.1988.10478639
[27]
Collar N.J. (1997)
[29]
Cornejo J.2012.Insights on psittacine nutrition through the study of free‐living chicks. PhD Thesis Texas A&M.
[34]
Dunning J.B. (2008)
[37]
Forshaw J.M. (1989)
[38]
Foster R.B. (1994)
[40]
Gilardi J.D.1996.Ecology of parrots in the Peruvian Amazon: habitat use nutrition and geophagy. PhD Thesis UC Davis.
[46]
2013 Intergovernmental Panel on Climate Change Cambridge UK IPCC T. Stocker D. Qin G.‐K. Plattner M. Tignor S. Allen J. Boschung A. Nauels Y. Xia V. Bex P. Midgley The physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change
[49]
Jones R.L. (1985)

Showing 50 of 102 references

Cited By
20
Clays and Clay Minerals
Metrics
20
Citations
102
References
Details
Published
Aug 03, 2017
Vol/Issue
160(1)
Pages
112-129
License
View
Funding
Earthwatch Institute
Cite This Article
Donald J. Brightsmith, Elizabeth A. Hobson, Gustavo Martinez (2017). Food availability and breeding season as predictors of geophagy in Amazonian parrots. Ibis, 160(1), 112-129. https://doi.org/10.1111/ibi.12515