scholarly journals Flight costs of long, sexually selected tails in hummingbirds

2009 ◽  
Vol 276 (1664) ◽  
pp. 2109-2115 ◽  
Author(s):  
Christopher James Clark ◽  
Robert Dudley
Keyword(s):  
Tail Length ◽  
Metabolic Cost ◽  
The Body ◽  
Flight Speed ◽  
Flight Performance ◽  
Forward Speed ◽  
Significant Interaction Effect ◽  
Body Drag ◽  
Flight Costs ◽  
Calypte Anna

The elongated tails adorning many male birds have traditionally been thought to degrade flight performance by increasing body drag. However, aerodynamic interactions between the body and tail can be substantial in some contexts, and a short tail may actually reduce rather than increase overall drag. To test how tail length affects flight performance, we manipulated the tails of Anna's hummingbirds ( Calypte anna ) by increasing their length with the greatly elongated tail streamers of the red-billed streamertail ( Trochilus polytmus ) and reducing their length by removing first the rectrices and then the entire tail (i.e. all rectrices and tail covert feathers). Flight performance was measured in a wind tunnel by measuring (i) the maximum forward speed at which the birds could fly and (ii) the metabolic cost of flight while flying at airspeeds from 0 to 14 m s −1 . We found a significant interaction effect between tail treatment and airspeed: an elongated tail increased the metabolic cost of flight by up to 11 per cent, and this effect was strongest at higher flight speeds. Maximum flight speed was concomitantly reduced by 3.4 per cent. Also, removing the entire tail decreased maximum flight speed by 2 per cent, suggesting beneficial aerodynamic effects for tails of normal length. The effects of elongation are thus subtle and airspeed-specific, suggesting that diversity in avian tail morphology is associated with only modest flight costs.

scholarly journals Kinematics Measurement and Power Requirements of Fruitflies at Various Flight Speeds

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4271
Author(s):  
Hao Jie Zhu ◽  
Mao Sun
Keyword(s):  
The Body ◽  
Flight Speed ◽  
Specific Power ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Body Angle ◽  
Flying Insects ◽  
Speed Range ◽  
Full Speed ◽  
Stroke Amplitude

Energy expenditure is a critical characteristic in evaluating the flight performance of flying insects. To investigate how the energy cost of small-sized insects varies with flight speed, we measured the detailed wing and body kinematics in the full speed range of fruitflies and computed the aerodynamic forces and power requirements of the flies. As flight speed increases, the body angle decreases and the stroke plane angle increases; the wingbeat frequency only changes slightly; the geometrical angle of attack in the middle upstroke increases; the stroke amplitude first decreases and then increases. The mechanical power of the fruitflies at all flight speeds is dominated by aerodynamic power (inertial power is very small), and the magnitude of aerodynamic power in upstroke increases significantly at high flight speeds due to the increase of the drag and the flapping velocity of the wing. The specific power (power required for flight divided by insect weigh) changes little when the advance ratio is below about 0.45 and afterwards increases sharply. That is, the specific power varies with flight speed according to a J-shaped curve, unlike those of aircrafts, birds and large-sized insects which vary with flight speed according to a U-shaped curve.

scholarly journals Air speeds of migrating birds observed by ornithodolite and compared with predictions from flight theory

2013 ◽  
Vol 10 (86) ◽  
pp. 20130419 ◽  
Author(s):  
C. J. Pennycuick ◽  
Susanne Åkesson ◽  
Anders Hedenström
Keyword(s):  
East Coast ◽  
Bird Species ◽  
The Body ◽  
Flight Performance ◽  
Number Range ◽  
Drag Coefficients ◽  
Dead Bird ◽  
Body Drag ◽  
Air Speed ◽  
Migrating Birds

We measured the air speeds of 31 bird species, for which we had body mass and wing measurements, migrating along the east coast of Sweden in autumn, using a Vectronix Vector 21 ornithodolite and a Gill WindSonic anemometer. We expected each species’ average air speed to exceed its calculated minimum-power speed ( V mp ), and to fall below its maximum-range speed ( V mr ), but found some exceptions to both limits. To resolve these discrepancies, we first reduced the assumed induced power factor for all species from 1.2 to 0.9, attributing this to splayed and up-turned primary feathers, and then assigned body drag coefficients for different species down to 0.060 for small waders, and up to 0.12 for the mute swan, in the Reynolds number range 25 000–250 000. These results will be used to amend the default values in existing software that estimates fuel consumption in migration, energy heights on arrival and other aspects of flight performance, using classical aeronautical theory. The body drag coefficients are central to range calculations. Although they cannot be measured on dead bird bodies, they could be checked against wind tunnel measurements on living birds, using existing methods.

Locomotor mimicry in butterflies? The associations of positions of centres of mass among groups of mimetic, unprofitable prey

1994 ◽  
Vol 343 (1304) ◽  
pp. 145-155 ◽  
Keyword(s):  
The Body ◽  
Flight Speed ◽  
Morphological Parameters ◽  
Flight Performance ◽  
Wing Base ◽  
Distinct Character ◽  
Components Analysis ◽  
Morphological Differences ◽  
Palatable Species ◽  
Radial Moments

With detailed measurements of flight-related morphological parameters of 18 species within the tribe Heliconiini and 10 of their non-heliconiine comimics, I found that morphological parameters relevant to flight biomechanics are associated with three escape tactics of these Neotropical butterflies: evasive flight, distastefulness, and mimicry. Two distinct character suites, one pertaining to the position of centre of body mass and another pertaining to wing shape, were identified using principal-components analysis. A third component correlated most highly with the position of centre of wing mass. Mimicry groups were best discriminated by the positions of centres of body and wing mass, suggesting that these features converged within mimicry groups. Centres of mass were positioned nearer to the wing base in mimicry groups composed of more palatable species, presumably decreasing the radial moments of inertia of the body and wings and increasing flight speed and turning performance. Predation has selected for body morphology that increases flight speed and manoeuvrability in palatable butterflies, whereas the morphology of distasteful species compromises flight performance. Convergent selection may reduce morphological differences of species within mimicry groups arising from distantly related lineages, and hence it may have enhanced the morphological diversification of palatable and unpalatable butterflies within lineages that have more recently evolved distastefulness.

scholarly journals Physical limits of flight performance in the heaviest soaring bird

2020 ◽  
Vol 117 (30) ◽  
pp. 17884-17890 ◽  
Author(s):  
H. J. Williams ◽  
E. L. C. Shepard ◽  
Mark D. Holton ◽  
P. A. E. Alarcón ◽  
R. P. Wilson ◽  
...  
Keyword(s):  
Environmental Parameters ◽  
Thermal Conditions ◽  
Metabolic Cost ◽  
Flight Time ◽  
Flight Performance ◽  
Flight Costs ◽  
Wide Range ◽  
Soaring Birds ◽  
Andean Condor ◽  
Vultur Gryphus

Flight costs are predicted to vary with environmental conditions, and this should ultimately determine the movement capacity and distributions of large soaring birds. Despite this, little is known about how flight effort varies with environmental parameters. We deployed bio-logging devices on the world’s heaviest soaring bird, the Andean condor (Vultur gryphus), to assess the extent to which these birds can operate without resorting to powered flight. Our records of individual wingbeats in >216 h of flight show that condors can sustain soaring across a wide range of wind and thermal conditions, flapping for only 1% of their flight time. This is among the very lowest estimated movement costs in vertebrates. One bird even flew for >5 h without flapping, covering ∼172 km. Overall, > 75% of flapping flight was associated with takeoffs. Movement between weak thermal updrafts at the start of the day also imposed a metabolic cost, with birds flapping toward the end of glides to reach ephemeral thermal updrafts. Nonetheless, the investment required was still remarkably low, and even in winter conditions with weak thermals, condors are only predicted to flap for ∼2 s per kilometer. Therefore, the overall flight effort in the largest soaring birds appears to be constrained by the requirements for takeoff.

Flight performance monitoring with optimal filtering applications

2019 ◽  
Vol 124 (1272) ◽  
pp. 170-188
Author(s):  
V. A. Deo ◽  
F. Silvestre ◽  
M. Morales
Keyword(s):  
Kalman Filter ◽  
Performance Monitoring ◽  
The Body ◽  
Flight Performance ◽  
Performance Parameters ◽  
Sideslip Angle ◽  
Fuel Flow ◽  
Aircraft Performance ◽  
Lift And Drag

ABSTRACTThis work presents an alternative methodology for monitoring flight performance during airline operations using the available inboard instrumentation system. This method tries to reduce the disadvantages of the traditional specific range monitoring technique where instrumentation noise and cruise stabilisation conditions affect the quality of the performance monitoring results. The proposed method consists of using an unscented Kalman filter for aircraft performance identification using Newton’s flight dynamic equations in the body X, Y and Z axis. The use of the filtering technique reduces the effect of instrumentation and process noise, enhancing the reliability of the performance results. Besides the better quality of the monitoring process, using the proposed technique, additional results that are not possible to predict with the specific range method are identified during the filtering process. An example of these possible filtered results that show the advantages of this proposed methodology are the aircraft fuel flow offsets, as predicted in the specific range method, but also other important aircraft performance parameters as the aircraft lift and drag coefficients (CL and CD), sideslip angle (β) and wind speeds, giving the operator a deeper understanding of its aircraft operational status and the possibility to link the operational monitoring results to aircraft maintenance scheduling. This work brings a cruise stabilisation example where the selected performance monitoring parameters such as fuel flow factors, lift and drag bias, winds and sideslip angle are identified using only the inboard instrumentation such as the GPS/inertial sensors, a calibrated anemometric system and the angle-of-attack vanes relating each flight condition to a specific aircraft performance monitoring result. The results show that the proposed method captures the performance parameters by the use of the Kalman filter without the need of a strict stabilisation phase as it is recommended in the traditional specific range method, giving operators better flexibility when analysing and monitoring fleet performance.

Steinernema borjomiense n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Georgia

Nematology ◽  
2018 ◽  
Vol 20 (7) ◽  
pp. 653-669 ◽  
Author(s):  
Oleg Gorgadze ◽  
Elena Fanelli ◽  
Manana Lortkhipanidze ◽  
Alberto Troccoli ◽  
Medea Burjanadze ◽  
...  
Keyword(s):  
New Species ◽  
18S Rrna ◽  
Entomopathogenic Nematode ◽  
Phylogenetic Analyses ◽  
Tail Length ◽  
Morphological Characters ◽  
18S Rrna Gene ◽  
The Body ◽  
Rrna Gene ◽  
A New Species

Summary A new species of entomopathogenic nematode, Steinernema borjomiense n. sp., was isolated from the body of the host insect, Oryctes nasicornis (Coleoptera: Scarabaeidae), in Georgia, in the territory of Borjomi-Kharagauli. Morphological characters indicate that the new species is closely related to species of the feltiae-group. The infective juveniles are characterised by the following morphological characters: body length of 879 (777-989) μm, distance between the head and excretory pore = 72 (62-80) μm, pharynx length = 132 (122-142) μm, tail length = 70 (60-80) μm, ratio a = 26.3 (23.0-29.3), H% = 45 (40-51), D% = 54 (47-59), E% = 102 (95-115), and lateral fields consisting of seven ridges (eight incisures) at mid-body. Steinernema borjomiense n. sp. was molecularly characterised by sequencing three ribosomal regions (the ITS, the D2-D3 expansion domains and the 18S rRNA gene) and the mitochondrial COI gene. Phylogenetic analyses revealed that S. borjomiense n. sp. differs from all other known species of Steinernema and is a member of the monticolum-group.

scholarly journals Hovering performance of Anna's hummingbirds ( Calypte anna ) in ground effect

2014 ◽  
Vol 11 (98) ◽  
pp. 20140505 ◽  
Author(s):  
Erica J. Kim ◽  
Marta Wolf ◽  
Victor Manuel Ortega-Jimenez ◽  
Stanley H. Cheng ◽  
Robert Dudley
Keyword(s):  
Wing Length ◽  
Ground Effect ◽  
The Body ◽  
Plane Angle ◽  
Metabolic Power ◽  
Wingbeat Frequency ◽  
Body Angle ◽  
Induced Flow ◽  
Induced Velocity ◽  
Calypte Anna

Aerodynamic performance and energetic savings for flight in ground effect are theoretically maximized during hovering, but have never been directly measured for flying animals. We evaluated flight kinematics, metabolic rates and induced flow velocities for Anna's hummingbirds hovering at heights (relative to wing length R = 5.5 cm) of 0.7 R , 0.9 R , 1.1 R , 1.7 R , 2.2 R and 8 R above a solid surface. Flight at heights less than or equal to 1.1 R resulted in significant reductions in the body angle, tail angle, anatomical stroke plane angle, wake-induced velocity, and mechanical and metabolic power expenditures when compared with flight at the control height of 8 R . By contrast, stroke plane angle relative to horizontal, wingbeat amplitude and wingbeat frequency were unexpectedly independent of height from ground. Qualitative smoke visualizations suggest that each wing generates a vortex ring during both down- and upstroke. These rings expand upon reaching the ground and present a complex turbulent interaction below the bird's body. Nonetheless, hovering near surfaces results in substantial energetic benefits for hummingbirds, and by inference for all volant taxa that either feed at flowers or otherwise fly close to plant or other surfaces.

Growth performance, correlation and regression estimates of seven-chicken strains in South-Western Nigeria

2020 ◽  
Vol 45 (2) ◽  
pp. 40-48
Author(s):  
A. J. Atansuyi ◽  
U. C. Ihendu ◽  
C. A. Chineke
Keyword(s):  
Body Weight ◽  
Growth Performance ◽  
Correlation Coefficients ◽  
Tail Length ◽  
Experimental Period ◽  
The Body ◽  
Coefficient Of Determination ◽  
Indigenous Chicken ◽  
Randomized Design ◽  
Study Results

This study was conducted to determine the growth performance, correlation and regression estimates of seven-chicken strains in South-western Nigeria using a total of 300 day-old chicks. The birds were divided into seven groups based on their strain. The seven strains are Normal feather (NF), Fulani ecotype (FE), Frizzle feather (FF), naked neck (NN) and Transylvania indigenous strains while Hubbard and Marshal were meat-type exotic chickens. There were forty- five (45) unsexed day-old chicks in each strain except the Frizzle feather that were 30 in number. Completely randomized design (CRD) was used for the trial that lasted for 8 weeks. The birds were fed experimental diets ad libitum throughout the period of the study. Results showed that there were significant differences (p<0.05) in the initial and final weights of the birds. It was observed that exotic strains weighed heavier (3569.73gHB) than their indigenous counterparts (1391.11gNF). However, the Fulani ecotype weighed heaviest (1840.99g) among Nigeria indigenous strains during the experimental period. This showed that FE strains are generally heavy breed chicken and could be incorporated into a meat producing indigenous chicken if improved upon. The result of the correlation coefficients showed that a very strong, positive and highly significant (P<0.001) relationship existed between body weights and linear body measurements as most of the values are (>0.40). All the body parameter examined had significant (p<0.01) and direct relationship with the body weight. Shoulder-to-tail length (STL) had the highest coefficient of 0.98.The high correlation estimates obtained in this study could be as a result of pleiotropy, heterozygosity or linkage of genes in the birds. The three functions were highly significant (p<0.05) for all the parameters studied. This shows that the functions well described the parameters. On the basis of coefficient of determination (R ), the body weight of poultry birds at any age can be predicted most accurately with BRG using cubic function.

scholarly journals Genotype, gestation length, season, parity and sex effects on growth traits of two rabbit breeds and their crosses

2014 ◽  
Vol 30 (4) ◽  
pp. 717-729 ◽  
Author(s):  
S.S.A. Egena ◽  
G.N. Akpa ◽  
I.C. Alemede ◽  
A. Aremu
Keyword(s):  
Growth Traits ◽  
Tail Length ◽  
The Body ◽  
Gestation Length ◽  
Body Measurements ◽  
Season Of Birth ◽  
Trunk Length ◽  
Body Dimensions ◽  
Sex Effects ◽  
Foundation Stock

One hundred and thirty rabbits were used to evaluate the effect of genotype, gestation length, season, parity and sex on growth traits of two breeds of rabbit and their crosses. The rabbit used for the experiment were breeds of the New Zealand White (NZW) and Chinchilla (CH) breed. Six breeding bucks (three/breed) and eighteen breeding does (nine/breed) served as the foundation stock. Traits measured include: body weight (BW), nose to shoulder length (NTS), shoulder to tail length (STL), heart girth (HG), trunk length (TL) and length of ear (LE). Results revealed that, BW of the rabbits were influenced (p<0.05) by genotype, gestation length and season. CH x (CH x NZW) progenies had better BW at 35-d and 49-d of age while NZW x CH progenies had better BW at 21-d of age. Kittens born late (32-34 days) had better BW at 21-d, 35-d and 49-d while kittens kindled during early dry season had better BW at 21-d, 35-d and 49-d. Genotype affected (p<0.05) all the body measurements at 21-d, 35-d and 49-d. Gestation length affected (p<0.05) all the body measurements except for NTS at 21-d and HG at 49-d respectively. Season of birth also influenced (p<0.05) all the body measurements except for LE 21-d. Parity and sex had no effect (p>0.05) on BW, NTS, STL, HG, TL and LE. It was concluded that genotype, gestation length and season influenced BW and body dimensions of the two breeds of rabbit and their crosses while parity and sex had no effect.

scholarly journals Elastic energy savings and active energy cost in a simple model of running

2021 ◽  
Vol 17 (11) ◽  
pp. e1009608
Author(s):  
Ryan T. Schroeder ◽  
Arthur D. Kuo
Keyword(s):  
Elastic Energy ◽  
Energy Cost ◽  
Energy Savings ◽  
Mechanical Energy ◽  
Metabolic Cost ◽  
The Body ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Mass Model ◽  
Human Running

The energetic economy of running benefits from tendon and other tissues that store and return elastic energy, thus saving muscles from costly mechanical work. The classic “Spring-mass” computational model successfully explains the forces, displacements and mechanical power of running, as the outcome of dynamical interactions between the body center of mass and a purely elastic spring for the leg. However, the Spring-mass model does not include active muscles and cannot explain the metabolic energy cost of running, whether on level ground or on a slope. Here we add explicit actuation and dissipation to the Spring-mass model, and show how they explain substantial active (and thus costly) work during human running, and much of the associated energetic cost. Dissipation is modeled as modest energy losses (5% of total mechanical energy for running at 3 m s-1) from hysteresis and foot-ground collisions, that must be restored by active work each step. Even with substantial elastic energy return (59% of positive work, comparable to empirical observations), the active work could account for most of the metabolic cost of human running (about 68%, assuming human-like muscle efficiency). We also introduce a previously unappreciated energetic cost for rapid production of force, that helps explain the relatively smooth ground reaction forces of running, and why muscles might also actively perform negative work. With both work and rapid force costs, the model reproduces the energetics of human running at a range of speeds on level ground and on slopes. Although elastic return is key to energy savings, there are still losses that require restorative muscle work, which can cost substantial energy during running.

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