This function creates a bird description object, which is basically just a list with predefined variable names. It is named a bird object, but could also contain a description of a bat or insect. Minimal input required to construct a bird are body mass, wing span and wing area (or wing aspect ratio). Other required variables will then be given default values, or they will be estimated from allometric relations from literature.
Bird(massTotal, wingSpan, wingArea, ...)bird object with variables required by the various power estimating functions (e.g. computeFlappingPower).
Total mass that needs to be lifted in flight in kg
The maximum distance between the wingtips in meters
The area of the fully stretched wings including the root area (left wing, right wing and area in between the wing roots)
Any other properties of a valid bird object (see details)
Marco Klein Heerenbrink
This function sets up a list of properties of a bird. This definition of the bird is then used by the other functions in the package to estimate flight performance. At least three properties need to be specified: massTotal, wingSpan and wingArea. Either wingSpan or wingArea could be replaced by aspectRatio; the missing variable will then be computed. If no other properties are specified, default values will be used. Wingspan and wingarea should be measured from the maximally stretched out wing as described in Pennycuick (2008): wingspan as the maximum distance between the wingtips and wingarea as the area from a trace including the root area (where the body is).
To specify custom properties, these can simply be added as additional arguments to the function. Note that massTotal needs to be the sum of massLoad, massFat and massEmpty. The function will recompute the total mass if the specified masses are inconsistent. Allometric relations use the empty weight. Muscle mass is part of the empty mass, and as such it is represented by muscleMass as a fraction. It is used in the estimation of the mechanical power available for flight (together with the muscle properties coef.activeStrain and coef.isometricStress). The variable type is used for selected allometric relationships that are specific to that particular group. Currently, bodyFrontalArea distinguishes between 'passerine' and anything else and basalMetabolicRate distinguishes between 'passerine', 'seabird', 'bat' and anything else.
name | String | Common name |
name.scientific | Sring | Scientific name |
source | String | Source for information |
massLoad | Numeric | Additional mass the bird is carrying (kg); 0 |
massFat | Numeric | Fat mass, i.e. fuel (kg); 0 |
massEmpty | Numeric | Empty mass, i.e. total mass - fat mass - load mass (kg) |
muscleFraction | Numeric | Fraction [0,1] of empty mass that makes up flight muscle; 0.17* |
type | String | Type of bird 'other'*, 'passerine'*, 'seabird', 'bat' |
bodyFrontalArea | Numeric | Reference body frontal area used for body drag (m2) |
wingbeatFrequency | Numeric | Typical wingbeat frequency (Hz) |
coef.profileDragLiftFactor | Numeric | Coefficient for lift dependent profile drag; 0.03 (Klein Heerenbrinkn et al. 2015) |
coef.bodyDragCoefficient | Numeric | Drag coefficient related to body frontal area; 0.2** |
coef.conversionEfficiency | Numeric | Efficiency Chemical to Mechanical energy; 0.23* |
coef.respirationFactor | Numeric | Multiplyer for metabolic overhead respiration; 1.1* |
coef.activeStrain | Numeric | Muscle duty cycle factor; 0.26* |
coef.isometricStress | Numeric | Maximum force produced per cross section muscle (Pa); 400000 (upper limit from Pennycuick & Rezende 1984) |
basalMetabolicRate | Numeric | Minimum energy consumption required for sustain life functions (W) *. |
* as in Flight 1.25 (Pennycuick 2008)
** Large body of data supporting higher body drag coefficients (>0.2) than in Flight 1.25 (0.1), e.g. Pennycuick et al. (1988), Hedenström & Liechti (2001), Henningsson & Hedenström (2011) and KleinHeerenbrink et al. (2016)
Hedenström, A. & Liechti, F. (2001) Field estimates of body drag coefficient on the basis of dives in passerine birds. J. Exp. Biol. 204, 1167–75.
Henningsson, P. & Hedenström, A. (2011) Aerodynamics of gliding flight in common swifts. J. Exp. Biol. 214, 382–93. tools:::Rd_expr_doi("10.1242/jeb.050609")
Klein Heerenbrink, M., Johansson, L. C. & Hedenström, A. (2015) Power of the wingbeat: modelling the effects of flapping wings in vertebrate flight. Proc. R. Soc. A 471. tools:::Rd_expr_doi("10.1098/rspa.2014.0952")
KleinHeerenbrink, M., Warfvinge, K. & Hedenström, A. (2016) Wake analysis of aerodynamic components for the glide envelope of a jackdaw (Corvus monedula). J. Exp. Biol. 219, 1572–1581. tools:::Rd_expr_doi("10.1242/jeb.132480")
Pennycuick, C. J. & Rezende, M. A. (1984) The specific power output of aerobic muscle, related to the power density of mitochondria. J. Exp. Biol., 108, 377–392.
Pennycuick, C. J., Obrecht III, H. H. & Fuller, M. R. (1988) Empirical estimates of body drag of large waterfowl and raptors. J. Exp. Biol. 135, 253–264.
Pennycuick, C. J. (2008). Modelling the flying bird. Amsterdam, The Netherlands: Elsevier.
computeAvailablePower, computeChemicalPower, computeFlappingPower, computeBodyFrontalArea, etc.
myBird = Bird(
massTotal = 0.215,
wingSpan = 0.67,
wingArea = 0.0652,
name = 'jackdaw',
type = 'passerine'
)
print(myBird)
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