Has the Australian Endemic Grey Falcon the Most Extreme Dietary Specialization among all Falco Species?
1
School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
2
CSIRO Land and Water, Winnellie, NT 0822, Australia
*
Author to whom correspondence should be addressed.
Academic Editor: Piotr Tryjanowski
Animals 2022, 12(12), 1582; https://doi.org/10.3390/ani12121582
Received: 19 May 2022
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Revised: 13 June 2022
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Accepted: 17 June 2022
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Published: 19 June 2022
(This article belongs to the Section Wildlife)
Simple Summary
The diet of an animal is one of the most informative aspects of how it interacts with its environment. A clear understanding of a species’ diet is, therefore, crucial for conservation considerations. The Grey Falcon is a rare and threatened raptor, found only in Australia’s vast arid and semi-arid zone. Its diet is subject to dispute, therefore, we studied, through direct observation during more than 17 years of fieldwork, the food that these birds ingested. We found that Grey Falcons of all ages fed almost exclusively on birds. No other food type was ever taken with any regularity. Our results suggest strongly that the Grey Falcon, throughout the year, throughout its life, and across its vast distribution, feeds almost exclusively on birds. We compared our results with the diets of the other species in the genus (Falco) and found that the Grey Falcon’s diet is the most extreme, more so than the diet of even those falcon species that are commonly considered to take exclusively birds, such as the Peregrine Falcon. Our evolutionary explanation of the unique dietary specialization of the Grey Falcon takes into account aspects of the species’ environment and relative prey availability.
A clear understanding of a species’ diet is crucial in understanding its spatio-temporal dynamics, and is, therefore, pertinent to conservation considerations. The diet of the Grey Falcon (Falco hypoleucos), a rare and threatened predator endemic to the Australian arid and semi-arid zone, is subject to diverging assertions; therefore, we studied its diet through direct observation of food ingestion during more than 17 years of fieldwork across the species’ distribution. We found that Grey Falcons of all ages fed almost exclusively on a single type of food, namely, birds, and non-avian food items never constituted a substantial portion of any individual’s diet. The extraordinary circumstances that were associated with the ingestion of non-avian food suggest strongly that, across its vast distribution, throughout the year, and throughout its life, the Grey Falcon feeds almost exclusively on birds. Further, we compared the diets of all Falco species and found that the dietary specialization is most extreme in the Grey Falcon, more so than even in the Taita (F. fasciinucha) and Peregrine Falcons (F. peregrinus). Based on aspects of the species’ environment and relative prey availability, we offer an evolutionary explanation of the apparently unique dietary specialization of the arid-adapted Grey Falcon.
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Keywords:
bird of prey; diet; Falco hypoleucos; food specialist; raptor; threatened species
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Externally hosted supplementary file 1
Doi: 10.17632/rprms92mjp.1
Link: https://doi.org/10.17632/rprms92mjp.1
Description: Grey Falcon (Falco hypoleucos) diet, from direct observations made between July 2006 and Sep 2021
MDPI and ACS Style
Schoenjahn, J.; Pavey, C.R.; Walter, G.H. Has the Australian Endemic Grey Falcon the Most Extreme Dietary Specialization among all Falco Species? Animals 2022, 12, 1582. https://doi.org/10.3390/ani12121582
AMA Style
Schoenjahn J, Pavey CR, Walter GH. Has the Australian Endemic Grey Falcon the Most Extreme Dietary Specialization among all Falco Species? Animals. 2022; 12(12):1582. https://doi.org/10.3390/ani12121582
Chicago/Turabian StyleSchoenjahn, Jonny, Chris R. Pavey, and Gimme H. Walter. 2022. "Has the Australian Endemic Grey Falcon the Most Extreme Dietary Specialization among all Falco Species?" Animals 12, no. 12: 1582. https://doi.org/10.3390/ani12121582
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