Hunter of scavenger? Predatory behaviour of extinct Haast’s eagle

Reconstruction of extinct Haast’s eagle and moa. Credit: John Megahan

Haast’s eagle is an extinct predatory bird from New Zealand that weighed 20 kg – nearly 50% more than the largest modern eagles. Previous investigations into the likely diet and predatory behaviour of this species are conflicting. Their beak morphology and bone scrolls around the nostrils are similar to vultures, suggesting they may have been a carrier feeder. Nevertheless, this view is not universally supported.

For this project, we were interested in finding out whether Haast’s eagle would been capable of taking down large-bodied prey, including moa (~20-200 kg). In extant birds of prey, skull and talon morphology has been linked to feeding behaviour. As such, we created skull and talon finite element models to assess the mechanical performance of Harpagornis relative to some modern accipitrids, including eagles and vultures, during simulations of various killing and feeding behaviours.

We have applied loads simulating a simple bite using scaled muscle forces estimated from modern buzzards (Buteo buteo), one lateral shaking, and two pulling (posterior, dorsoventral) behaviours, as well as talon flexion and gripping. We are currently preparing the manuscript for publication.


van Heteren AH, Tsang LR, Sansalone G, Ross P, Ledogar JA, Attard MRG, Sustaita D, Clausen P, Scofield P, Wroe S (In prep) The feeding biomechanics of Haast’s eagle (Harpagornis Moorei)