Theres a new paper published by Jerry Olsen and colleagues on the
diets of WT and Little Eagles in the Canberra area...
Olsen, J., D. Judge, E. Fuentes, A. B. Rose and S. J. S. Debus (2010).
“Diets of Wedge-tailed Eagles (Aquila audax) and Little Eagles (Hieraaetus
morphnoides) Breeding Near Canberra, Australia ” Journal of
Raptor Research 44(1): 50-61.
Abstract: Recent concern about the decline of the Little Eagle
(Hieraaetus morphnoides) in southeastern Australia has raised questions
about whether Wedge-tailed Eagles (Aquila audax) might be implicated in
this decline. The ecology, including the diet, of Little Eagles is
rather poorly known. The diet of the Wedge-tailed Eagle is better
documented, but the overlap in prey used by the two eagles has been
little studied. Near Canberra between July 2002 and January 2008, we
identified 1421 and 192 prey items from nests of Wedge-tailed Eagles
and Little Eagles, respectively. Wedge-tailed Eagles' diet was similar
to that reported elsewhere. In addition to European rabbits
(Oryctolagus cuniculus), Little Eagles specialized on birds, but tended
to avoid macropods, a main prey of Wedge-tailed Eagles, and there was
little overlap in prey used by the two eagle species. Although
Standardised Food Niche Breadth and Shannon Diversity Index were
similar for the two eagles, Wedge-tailed Eagles captured significantly
larger prey, as indicated by the difference in Geometric Mean Prey
Weight, 1298 g for Wedge-tailed Eagles and 249 g for Little Eagles,
which reflected the fivefold difference in mass between male Little
Eagles and male Wedge-tailed Eagles. We suggest that direct competition
for prey probably was not the cause of the Little Eagle decline.
Robin Hide
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