Ontogeny of aerial righting and wing flapping in juvenile birds

Mechanisms of aerial righting in juvenile Chukar Partridge (Alectoris chukar) were studied from hatching through 14 days post hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e., wing assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development, and are potentially relevant to understanding the origins of avian flight

Shifts in stability and control effectiveness during evolution of Paraves support aerial maneuvering hypotheses for flight origins

The capacity for aerial maneuvering shaped the evolution of flying animals. Here we evaluate consequences of aviaian morphology for aerial performance (1,2) by quantifying static stability and control effectiveness of physical models (3) for numerous taxa sampled from within the lineage leading to birds (Paraves, 4). Results of aerodynamic testing are mapped phylogenetically (5-9) to examine how maneuvering characteristics correlate with tail shortening, fore- and hindwing elaboration, and other morphological features (10). In the evolution of the Avialae we observe shifts from static stability to inherently unstable aerial planforms; control effectiveness also migrated from tails to the forewings. These shifts suggest that some degree of aerodynamic control and and capacity for maneuvering preceded the evolution of strong power stroke. The timing of shifts also suggests some features normally considered in light of development of a power stroke may play important roles in control.Comment: 12 pages, 6 figures, 1 supplemental figures and 5 supplemental table

Data from: Ontogeny of aerial righting and wing flapping in juvenile birds

Mechanisms of aerial righting in juvenile chukar partridge (Alectoris chukar) were studied from hatching to 14 days-post-hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose-down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e. wing-assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development and are potentially relevant to understanding the origins of avian flight

Raw data and R code for plotting

Data and R code to produce figure 2, which gives (a) Percent righting (N=26 birds, number of drops as indicated) and (b) righting mode (N=26 birds, number of successful rightings as indicated), and (c) vertical force production (N=5 birds, except for N=1 at 14 dph; data represent mean ± 1 s.d.) versus age in Chukar Partridge. Righting via roll, as accomplished by asymmetric wing and leg movements, is used prior to 14 dph. Around 9 dph, birds switch to righting via pitch using symmetric wing motions, and vertical force production increases concomitantly

Aerodynamic characteristics of feathered dinosaur shapes measured using physical models: a comparative study of maneuvering

<p>Cite as:  Cam, Chun, Huynh, Mehrabani, Tse, and Evangelista 2011.  Journal of Vertebrate Paleontology 31(Supplement 2):129-130. </p> <p> </p> <p>Society of Vertebrate Paleontology Annual Meeting 2011, Las Vegas NV. </p> <p> </p> <p>Related manuscript submitted and in review. </p