Back in 2008, Mark Witton and I argued that azhdarchids possess a suite of anatomical features that make it most likely that they were terrestrial stalkers: that is, that – while they were adept, specialised soarers, great at rapidly covering extraordinary distances – they seemingly foraged on foot in both wooded and open terrestrial environments, walking quadrupedally with an efficient, narrow gait, reaching down with their long necks and bills to grab small animals, bits of carrion and perhaps fruits and other edible bits of plants (Witton & Naish 2008). Azhdarchids don’t have any precise modern analogues, but we suggested that their behaviour and lifestyle most closely resembled that of modern ground horbills and terrestrial-foraging populations of marabou stork. [Adjacent ground hornbill photo - I really, really love the composition of this image - by Rod Waddington.]
This view of terrestrial stalking azhdarchids receives support from the anatomy and proportions of these animals, from the environments and animal communities in which their remains are preserved, and from trackway evidence (there’s a long, continuous trackway preserved in Upper Cretaceous Korean sediments, seemingly made by a quadrupedally walking azhdarchid*) (Witton & Naish 2008).
* A trackway argued to have been produced by a bipedal giant azhdarchid was recently published. There are some issues with the conclusions of this study. Stay tuned.
If you need a refresher on any of this, check out the articles linked to below – there’s quite a bit on azhdarchids in the Tet Zoo archives, plus the Witton & Naish (2008) paper is open-access and available to all.