UNASSIGNED: Flying animals must successfully contend with obstacles in their natural environments. Inspired by the robust manoeuvring abilities of flying animals, unmanned aerial systems are being developed and tested to improve flight control through cluttered environments. We previously examined steering strategies that pigeons adopt to @entity238 through an array of vertical obstacles (VOs). Modelling VO flight guidance revealed that pigeons steer towards larger visual gaps when making fast steering decisions. In the present experiments, we recorded three-dimensional flight kinematics of pigeons as they flew through randomized arrays of horizontal obstacles (HOs). We found that pigeons still decelerated upon approach but flew faster through a denser array of HOs compared with the VO array previously tested. Pigeons exhibited limited steering and chose gaps between obstacles most aligned to their immediate flight direction, in contrast to VO navigation that favoured widest gap steering. In addition, pigeons navigated past the HOs with more variable and decreased wing @entity64 span and adjusted their wing @entity64 plane to reduce contact with the obstacles. Variability in wing extension, @entity64 plane and wing @entity64 path was greater during HO flight. Pigeons also exhibited pronounced head movements when negotiating HOs, which potentially serve a visual function. These @entity910 were most pronounced in the horizontal (flight direction) and vertical directions, consistent with engaging motion vision mechanisms for obstacle detection. These results show that pigeons exhibit a keen kinesthetic sense of their body and wings in relation to obstacles. Together with aerodynamic flapping flight mechanics that favours vertical manoeuvring, pigeons are able to navigate HOs using simple rules, with remarkable success.

Rules to XXXX by: pigeons navigating horizontal obstacles limit steering by selecting gaps most aligned to their flight direction.

@entity910 :: ('MESH:D004409', 'Disease') :: ['head-bobbing-like movements'] @entity64 :: ('MESH:D020521', 'Disease') :: ['stroke'] @entity238 :: ('7227', 'Species') :: ['fly']
@entity238 :: (7227,Species) :: ['fly']
