Morphology, muscle capacity, skill, and maneuvering ability in hummingbirds

Dakin, Roslyn; Segre, Paolo S.; Straw, Andrew; Altshuler, Douglas L.

doi:10.1126/science.aao7104

Cited by 69 publications

(119 citation statements)

References 57 publications

(65 reference statements)

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“…They metabolize nectar sugar rapidly and efficiently (Karasov et al 1986). Agile hovering flight (Dakin et al 2018) gives them an exceptional ability to approach and handle flowers without landing. They possess acute color vision and lack innate preference for colors ranging from near UV to long red wavelengths (Stiles 1976;Goldsmith and Goldsmith 1979;Lunau et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Atypical Flowers Can Be as Profitable as Typical Hummingbird Flowers

Waser

CaraDonna

Price

2018

The American Naturalist

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In western North America, hummingbirds can be observed systematically visiting flowers that lack the typical reddish color, tubular morphology, and dilute nectar of "hummingbird flowers." Curious about this behavior, we asked whether these atypical flowers are energetically profitable for hummingbirds. Our field measurements of nectar content and hummingbird foraging speeds, taken over four decades at multiple localities, show that atypical flowers can be as profitable as typical ones and suggest that the profit can support 24-h metabolic requirements of the birds. Thus, atypical flowers may contribute to successful migration of hummingbirds, enhance their population densities, and allow them to occupy areas seemingly depauperate in suitable resources. These results illustrate what can be gained by attending to the unexpected.

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Section: Introductionmentioning

confidence: 99%

Atypical Flowers Can Be as Profitable as Typical Hummingbird Flowers

Waser

CaraDonna

Price

2018

The American Naturalist

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“…Previous research has shown that species with lower wing-loading also perform faster rotations and more sharp turns [29], both of which were also associated with an individual's overall unpredictability in our analysis. However, contrary to the facilitation hypothesis, we found that unpredictability was not related to burst muscle capacity, one of the most important traits that determines power generation for flying hummingbirds [28,32,44].…”

Section: Discussionmentioning

confidence: 57%

“…Next, we evaluated which morphological and muscle traits best explain an individual's overall unpredictability. Measures of body mass, wing loading, and aspect ratio were taken from the same individuals in the maneuvering trials [29]. We obtained estimates of species-average muscle capacity based on previous studies that used a transient load-lifting assay [29,32,44].…”

Section: (D) Maneuvers Morphology and Entropymentioning

confidence: 99%

“…Previous studies of flying hummingbirds have shown that the kinematics of the wings and body are influenced by interindividual variation in body mass, flight muscle mass, and wing loading [31][32][33]. More recently, these morphological traits have also been mapped to individual differences in the use and performance of different maneuvers defined in Table 1 [28,29,34]. For example, flight muscle capacity is correlated with enhanced performance on multiple translational, rotational, and turning performance metrics.…”

Section: Introductionmentioning

confidence: 99%

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Unpredictable hummingbirds: Flight path entropy is constrained by speed and wing loading

Berberi

Segre

Altshuler

et al. 2020

Preprint

Self Cite

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Unpredictable movement can provide an advantage when animals avoid predators and other threats. Previous studies have examined how varying environments can elicit unpredictable movement, but the intrinsic causes of complex, unpredictable behavior are not yet known. We addressed this question by analyzing >200 hours of flight performed by hummingbirds, a group of aerial specialists noted for their extreme agility and escape performance. We used information theory to calculate unpredictability based on the positional entropy of short flight sequences during 30-min and 2-hour trials. We show that a bird’s entropy is repeatable, with stable differences among individuals that are negatively correlated with wing loading: birds with lower wing loading are less predictable. Unpredictability is also positively correlated with a bird’s overall acceleration and rotational performance, and yet we find that moment-to-moment changes in acceleration and rotational velocities do not directly influence entropy. This indicates that biomechanical performance must share an underlying basis with a bird’s ability to combine maneuvers into unpredictable sequences. Contrary to expectations, hummingbirds achieve their highest entropy at relatively slow speeds, pointing to a fundamental trade-off whereby individuals must choose to be either fast or unpredictable.

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“…vertical ascent are also capable of controlled high-speed shaking (Movie 3), a behavior otherwise only known during hovering in rain (Ortega-Jimenez and Dudley, 2012; this aerial shaking sequence was not included in either the data tables or power estimates). Such precise positional control during rapid ascent, as well as the vertical glide, further extend the range of novel maneuvers (see also Dakin et al, 2018) that have been recently described for this amazing lineage of birds.…”

Section: Discussionmentioning

confidence: 59%

Ascending flight and decelerating vertical glides in Anna's hummingbirds

Ortega-Jimenez

Dudley

2018

Journal of Experimental Biology

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Hummingbirds are observationally well known for their capacity to vertically ascend whilst hovering, but the underlying mechanics and possible energetic limits to ascent rates are unclear. Decelerations during vertical ascent to a fixed target may also be associated with specific visual responses to regulate the body's trajectory. Here, we studied climbing flight and subsequent deceleration in male Anna's hummingbirds (Calypte anna) over an approximately 2 m vertical distance. Birds reached vertical speeds and accelerations up to ∼4 m s −1 and 10 m s −2 , respectively, through the use of flapping frequencies as high as 56 Hz and stroke amplitudes slightly greater than 180 deg. Total mass-specific power at maximal ascent speed was up to 92 W kg −1 body mass. Near the end of the ascending trajectory, all individuals decelerated ballistically via cessation of flapping and folding of wings over the body without losing control, a behavior termed here a vertical glide. Visual modulation of the deceleration trajectory during ascent was indicated by a constant value (∼0.75) for the first derivative of the time-to-contact to target.Our results indicate that hummingbirds in rapid vertical ascent expended near-maximal power output during flight, but also tightly controlled their subsequent deceleration during the vertical glide.

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Morphology, muscle capacity, skill, and maneuvering ability in hummingbirds

Cited by 69 publications

References 57 publications

Atypical Flowers Can Be as Profitable as Typical Hummingbird Flowers

Atypical Flowers Can Be as Profitable as Typical Hummingbird Flowers

Unpredictable hummingbirds: Flight path entropy is constrained by speed and wing loading

Ascending flight and decelerating vertical glides in Anna's hummingbirds

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