How swifts control their glide performance with morphing wings

Lentink, David; Müller, Ulrike K.; Stamhuis, Eize; Kat, Roeland de; Gestel, W. van; Veldhuis, L.L.M.; Henningsson, Per; Hedenström, Anders; Videler, John J.; Leeuwen, J.L. van

doi:10.1038/nature05733

Cited by 267 publications

(244 citation statements)

References 21 publications

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“…A major characteristic of the wings of birds is that they morph extensively during flapping ([16,71,72]; figure 2) and during intermittent flight including bounds and glides [73][74][75]. Such morphing probably has significant effects upon aerodynamic function [72,74,76], but direct tests for such effects in most cases await new research.…”

Section: Muscle Function Proximal To Distal In the Wingmentioning

confidence: 99%

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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%

“…Such morphing probably has significant effects upon aerodynamic function [72,74,76], but direct tests for such effects in most cases await new research. Direct measures of strain reveal that the biceps and triceps function for elbow flexion, extension and stabilization [77].…”

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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“…Several studies have measured the drag of birds [17][18][19][20], bats [21] or their wings [22][23][24][25]. However, few studies have explicitly described the profile drag polar.…”

Section: Wake Optimizationmentioning

confidence: 99%

Power of the wingbeat: modelling the effects of flapping wings in vertebrate flight

KleinHeerenbrink

Johansson

Hedenström³

2015

Proc. R. Soc. A.

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Animal flight performance has been studied using models developed for man-made aircraft. For an aeroplane with fixed wings, the energetic cost as a function of flight speed can be expressed in terms of weight, wing span, wing area and body area, where more details are included in proportionality coefficients. Flying animals flap their wings to produce thrust. Adopting the fixed wing flight model implicitly incorporates the effects of wing flapping in the coefficients. However, in practice, these effects have been ignored. In this paper, the effects of reciprocating wing motion on the coefficients of the fixed wing aerodynamic power model for forward flight are explicitly formulated in terms of thrust requirement, wingbeat frequency and strokeplane angle, for optimized wingbeat amplitudes. The expressions are obtained by simulating flights over a large parameter range using an optimal vortex wake method combined with a low-level blade element method. The results imply that previously assumed acceptable values for the induced power factor might be strongly underestimated. The results also show the dependence of profile power on wing kinematics. The expressions introduced in this paper can be used to significantly improve animal flight models.

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“…Birds modulate their airspeed in relation to the availability of rising air, reducing their airspeed in updraughts and increasing their airspeed as they glide between them [29]. This may also be associated with postural changes if, in an analogous manner to gliders, airspeed is affected by changes in the forward pitch as well as modulating wing area by altering the shape of the wings [30,31].…”

mentioning

confidence: 99%

Can accelerometry be used to distinguish between flight types in soaring birds?

et al. 2015

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Background: Accelerometry has been used to identify behaviours through the quantification of body posture and motion for a range of species moving in different media. This technique has not been applied to flight behaviours to the same degree, having only been used to distinguish flapping from soaring flight, even though identifying the type of soaring flight could provide important insights into the factors underlying movement paths in soaring birds. This may be due to the complexities of interpreting acceleration data, as movement in the aerial environment may be influenced by phenomena such as centripetal acceleration (pulling-g). This study used high-resolution movement data on the flight of free-living Andean condors (Vultur gryphus) and a captive Eurasian griffon vulture (Gyps fulvus) to examine the influence of gravitational, dynamic and centripetal acceleration in different flight types. Flight behaviour was categorised as thermal soaring, slope soaring, gliding and flapping, using changes in altitude and heading from magnetometry data. We examined the ability of the k-nearest neighbour (KNN) algorithm to distinguish between these behaviours using acceleration data alone. Results:Values of the vectorial static body acceleration (VeSBA) suggest that these birds experience relatively little centripetal acceleration in flight, though this varies between flight types. Centripetal acceleration appears to be of most influence during thermal soaring; consequently, it is not possible to derive bank angle from smoothed values of lateral acceleration. In contrast, the smoothed acceleration values in the dorso-ventral axis provide insight into body pitch, which varied linearly with airspeed. Classification of passive flight types via KNN was limited, with low accuracy and precision for soaring and gliding. Conclusion:The importance of soaring was evident in the high proportion of time each bird spent in this flight mode (52.17-84.00 %). Accelerometry alone was limited in its ability to distinguish between passive flight types, though smoothed values in the dorso-ventral axis did vary with airspeed. Other sensors, in particular the magnetometer, provided powerful methods of identifying flight behaviour and these data may be better suited for automated behavioural identification. This should provide further insight into the type and strength of updraughts available to soaring birds.

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How swifts control their glide performance with morphing wings

Cited by 267 publications

References 21 publications

Evolution of avian flight: muscles and constraints on performance

Evolution of avian flight: muscles and constraints on performance

Power of the wingbeat: modelling the effects of flapping wings in vertebrate flight

Can accelerometry be used to distinguish between flight types in soaring birds?

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