Landscape heterogeneity and novelty drive avian oscillatory flight behaviour during forebrain Wulst-Dependent visual map learning

Homing pigeons rely on familiar landscape features in learning a visual
map, which is orchestrated by the forebrain visual Wulst and hippocampus.
Recent GPS tracking studies showed that pigeons with damage to the visual
Wulst or hippocampus exhibited a still poorly understood, persistent
oscillatory flight behaviour, unlike intact pigeons whose oscillations
decrease with experience. To evaluate whether landscape heterogeneity
influences the extent of these oscillations, we compared the flight
behaviour of both intact and Wulst-lesioned pigeons when flying over the
sea vs land. Regardless of treatment, pigeons exhibited less oscillatory
flight behaviour over the homogeneous landscape of the sea. Further
releases from familiar and unfamiliar sites tested whether oscillatory
flight behaviour may be influenced by the level of familiarity with the
landscape. Indeed, intact pigeons reduced their oscillatory behaviour as
landscape familiarity increased. By contrast, Wulst-damaged pigeons
persisted in displaying robust oscillatory flight behaviour regardless of
the level of landscape familiarity, suggesting that previously experienced
landscapes remained relatively unfamiliar to them. The data support the
hypotheses that oscillatory flight behaviour reflects active visual
scanning, most pronounced over novel, heterogeneous landscapes,
contributing to visual map learning. Further, the data suggest a crucial
role of the forebrain Wulst for such learning.