Optic flow stabilizes flight in ruby-throated hummingbirds

Abstract

Flying birds rely on visual cues for retinal image stabilization by negating rotation-induced optic flow, the motion of the visual panorama across the retina, through corrective eye and head movements. In combination with vestibular and proprioceptive feedback, birds may also use visual cues to stabilize their body during flight. Here, we test whether artificially induced wide-field motion generated through projected visual patterns elicits maneuvers in body orientation and flight position, in addition to stabilizing vision. To test this hypothesis, we present hummingbirds flying freely within a 1.2 m cylindrical visual arena with a virtual surround rotated at different speeds about its vertical axis. The birds responded robustly to these visual perturbations by rotating their heads and bodies with the moving visual surround, and by adjusting their flight trajectories, following the surround. Thus, similar to insects, hummingbirds appear to use optic flow cues to control flight maneuvers as well as to stabilize their visual inputs.

Visual Sensory Signals Dominate Tactile Cues during Docked Feeding in Hummingbirds

“…The result that hummingbirds are not tracking the feeder is surprising and novel. Our results for docked hovering show that hummingbirds use the visual background to adjust body position, just as was previously shown for undocked hovering where no flower interaction is involved (Goller and Altshuler, 2014 ; Ros and Biewener, 2016 ). This is not the case for hawkmoths, which similarly use visual motion to stabilize body position, but also use visual cues from feeders to track oscillations up to 5 Hz in forward-backward directions (Farina et al, 1994 ) and 2–3 Hz laterally (Sponberg et al, 2015 ; Stöckl et al, 2017 ).…”

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

“…Birds and insects rely heavily on visual cues for short-range navigation to avoid obstacles, pursue prey [3][4][5] and select flight paths [6][7][8][9][10][11][12][13], whereas many bats and some specialized species of birds [14,15] rely on echolocation when foraging and during transit flights [16][17][18][19]. When flying through narrow openings, birds demonstrate a strong kinesthetic sense of body position and movement with respect to nearby obstacles, reducing their risk of wing and/or body damage associated with obstacle contacts [20][21][22].…”

Clinical findings and normative ocular data for free‐living Anna's (Calypte anna) and Black‐chinned (Archilochus alexandri) Hummingbirds

“…Intraocular pressure was measured in 362 eyes (183 birds; 140 Anna's and 43 Black-chinned Hummingbirds; Table 1). Mean AE SD (range) IOP for all birds was 11.12 AE 2.20 (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) Table 1). Mean AE SD (range) refractive error was +0.32 AE 0.33 (À0.25 to +1) D, with 82% of eyes being emmetropic (i.e.…”

“…1,2 The intricate flight behavior and maneuverability of hummingbirds during flight have led to an interest in hummingbird vision, although studies of the ocular anatomy and physiology of the hummingbird eye are limited to a few descriptions of retinal architecture and spectral sensitivity, 3,4 visual fields (LP Tyrrell, personal communication), and central vision. [5][6][7][8][9][10][11] Hummingbirds were initially reported to possess two foveae in each retina, 12 although recent studies on retinal architecture suggest that hummingbirds have a single central fovea and a temporal area centralis (LP Tyrrell, personal communication). 4 Hummingbirds have a welldeveloped visual system enabling successful performance of a number of visually demanding tasks such as precision foraging, 1,13,14 high-velocity, agile flight, 2,13,15 and intraspecies communication.…”