Anatomy and histochemistry of spread‐wing posture in birds. 4. Eagles soar with fast, not slow muscle fibres

Meyers, Ron A.; McFarland, Joshua C.

doi:10.1111/azo.12125

Cited by 8 publications

(5 citation statements)

References 33 publications

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“…Exceptions to this pattern are certain soaring birds that exhibit deep accessory bellies composed of slow-twitch fibres [66,67]. However, not all soaring species have this accessory [68,69]. The supracoracoideus accomplishes upstroke, including long-axis rotation of the humerus [70], and it, along with other shoulder muscles and the acrocoracohumeral ligament [17] stabilizes the shoulder.…”

Section: Muscle Function Proximal To Distal In the Wingmentioning

confidence: 99%

Evolution of avian flight: muscles and constraints on performance

Tobalske¹

2016

Phil. Trans. R. Soc. B

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One contribution of 17 to a theme issue 'Moving in a moving medium: new perspectives on flight'. Competing hypotheses about evolutionary origins of flight are the 'fundamental wing-stroke' and 'directed aerial descent' hypotheses. Support for the fundamental wing-stroke hypothesis is that extant birds use flapping of their wings to climb even before they are able to fly; there are no reported examples of incrementally increasing use of wing movements in gliding transitioning to flapping. An open question is whether locomotor styles must evolve initially for efficiency or if they might instead arrive due to efficacy. The proximal muscles of the avian wing output work and power for flight, and new research is exploring functions of the distal muscles in relation to dynamic changes in wing shape. It will be useful to test the relative contributions of the muscles of the forearm compared with inertial and aerodynamic loading of the wing upon dynamic morphing. Body size has dramatic effects upon flight performance. New research has revealed that mass-specific muscle power declines with increasing body mass among species. This explains the constraints associated with being large. Hummingbirds are the only species that can sustain hovering. Their ability to generate force, work and power appears to be limited by time for activation and deactivation within their wingbeats of high frequency. Most small birds use flap-bounding flight, and this flight style may offer an energetic advantage over continuous flapping during fast flight or during flight into a headwind. The use of flap-bounding during slow flight remains enigmatic. Flap-bounding birds do not appear to be constrained to use their primary flight muscles in a fixed manner. To improve understanding of the functional significance of flap-bounding, the energetic costs and the relative use of alternative styles by a given species in nature merit study.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. OverviewMuscles are obviously key to the capacity of birds for flight, and the goal of this review is to explore current hypotheses of the ways muscles permit and constrain this capacity. Insight into the phylogeny of birds is improving rapidly, and this offers great promise for improving understanding of how evolution transformed ancestral theropod forms [1] into the derived, volant bird species we observe today. Genomic study [2][3][4] and the extraordinary rate of new discovery of fossil dinosaurs [5][6][7][8][9][10] have provided rich phylogenetic hypotheses from which we can begin to test patterns of historical transformation [11]. Concurrently, modern empirical and modelling techniques in comparative biomechanics offer new ways of testing hypotheses that link form and function. These include in vivo and in situ measures of the contractile behaviour of muscle [12 -14]: high-speed, three-dimensional videography that can reveal details of wing motion [15,16]; X-ray videography of skeletal kinematics [16,17]; particle ima...

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Section: Muscle Function Proximal To Distal In the Wingmentioning

confidence: 99%

Evolution of avian flight: muscles and constraints on performance

Tobalske¹

2016

Phil. Trans. R. Soc. B

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“…As George and Berger (1966) noted, the wing muscle configuration is relatively similar in almost all groups of birds and the features of falcons and caracaras studied here agree with this observation. However, the few exceptions found in the muscles between these two subfamilies are related to versatility of the muscles that are adapted to a variety of activities (Meyers & McFarland, 2016). These differences in certain muscles generate an impact in their functioning (George & Berger, 1966), which, in turn, is reflected in the type of flight and its use.…”

Section: Discussionmentioning

confidence: 99%

Flight muscles in falcons (Falconiformes, Falconinae): A quantitative approach

Mosto

Picasso

Montes

et al. 2021

The Anatomical Record

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The family Falconidae has contrasting behaviors on its flight within the subfamilies. Falcons are primarily aerial predators requiring accuracy, high speed, and controlled movements during flight. Caracaras are generalists that seek food while walking and their flight is characterized as slow and erratic. We aimed to explore the muscle mass of the primary wing muscles in several species of Falconinae and to identify possible differences related to the role that these muscles perform during flight. We studied 34 wing muscles in 11 specimens of five species of falcons. The percentage of each muscle with respect to body mass was calculated as well as the total wing muscle mass. The search for differences between muscles of falcons and caracaras was analyzed using Bayesian statistical inference. Published data from Polyborinae were used for comparison. Five muscles were significantly different between both subfamilies mm. latissimus dorsi pars caudalis, biceps brachii, extensor carpi radialis, flexor digitorum superficialis, and extensor digitorum communis. The first two muscles were larger in Polyborinae, which could be useful to achieve more strength and stabilization. In falcons the last three muscles listed were larger, which might be associated with their fast and acrobatic flight. Variations in certain muscles generate, in turn, differences in function, which is reflected in their type of flight and its use. These findings reinforce the modular character of the locomotor system of birds whereby the regions involved in locomotion can have morphological peculiarities according to their lifestyle.

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“…Flexion-extension and stabilisation of the wing at the elbow and wrist are fundamental for gliding and soaring birds (Meyers 1993). Analyses of the fibre type composition of the BR, triceps muscles (ST and HT) and ECR in the albatross (Meyers and Stakebake 2005), golden eagle (Meyers and McFarland 2016), California gull (Meyers and Mathias 1997), double-crested cormorant (Meyers 1997), and American kestrel (Meyers 1992) demonstrated that these muscles contain percentages of both slow and fast fibres that suggest a postural role in maintaining the wing fixed in an folded or extended position, such as gliding and soaring. Furthermore, an electromyographic study of American kestrel identified activity of the triceps muscles during gliding when extension of the elbow was observed (Meyers 1993).…”

Section: Wing Mass Distribution and Its Relationship With Flight And mentioning

confidence: 99%

Functional morphology of the forelimb musculature reflects flight and foraging styles in aquatic birds

2021

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Aquatic birds show a great diversity of locomotion styles and wing morphologies, from penguins that are fully specialized for an aquatic life to species of aerial flyers that also use their wings for underwater propulsion (e.g. auks and shearwaters). Moving between the air–water interface exerts conflicting pressures on the body and wing anatomy of diving birds. In this work, we investigated the functional morphology of the forelimb musculature of 18 species of aquatic birds that display a variety of flight and foraging styles. Muscle architecture was related to function, with special emphasis on muscle mass. Dissections of one of the forelimbs of 20 specimens of waterbirds were performed to obtain numerical data of muscle architecture. Total wing muscle mass scaled isometrically to body mass1.0, whereas fascicle length scaled to muscle mass0.284, which is consistent with previous results of scaling in wings of raptors. A principal component analysis (PCA) of normalised muscle masses resulted in a biplot where three main morphological groups can be distinguished. Anatids (ducks and geese) occupy a space represented by muscles that are activated during downstroke. Auks and penguins clustered together in a region dominated by muscles that assist in wing elevation and showed a degree of hypertrophy. The rest of the species grouped together in the lower limits of both PCs where muscles that facilitate wing flexion–extension and stabilisation are loaded. The distribution of mass in the wing muscles of the aquatic birds seemed to be related to flight and foraging style and showed non-significant influence of shared phylogenetic history (Kmult: 0.71, p value: 0.083, 10,000 permutations).

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Anatomy and histochemistry of spread‐wing posture in birds. 4. Eagles soar with fast, not slow muscle fibres

Cited by 8 publications

References 33 publications

Evolution of avian flight: muscles and constraints on performance

Evolution of avian flight: muscles and constraints on performance

Flight muscles in falcons (Falconiformes, Falconinae): A quantitative approach

Functional morphology of the forelimb musculature reflects flight and foraging styles in aquatic birds

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