Hummingbirds rapidly respond to the removal of visible light and control a sequence of rate-commanded escape maneuvers in milliseconds
Data files
Jul 16, 2024 version files 79.64 MB
-
Data_S1.mat
79.63 MB
-
README.md
2.97 KB
Abstract
Hummingbirds routinely execute a variety of stunning aerobatic feats, which continue to challenge current notions of aerial agility and controlled stability in biological systems. Indeed, the control of these amazing maneuvers is not well understood. Here we examined how hummingbirds control a sequence of maneuvers within milliseconds and tested whether and when they use vision during this rapid process. We repeatedly elicited escape flights in Calliope hummingbirds and removed visible light during each maneuver at various instants and quantified their flight kinematics and responses. We show that the escape maneuvers were composed of rapidly-controlled sequential modules including evasion, reorientation, nose-down dive, forward flight, and nose-up to hover. The hummingbirds did not respond to the light removal during evasion and reorientation until a critical light-removal time; afterward, they showed two categories of luminance-based responses that rapidly altered maneuvering modules to terminate the escape. We also show that hummingbird maneuvers were rate-commanded and required no active braking, i.e., their body angular velocities were proportional to the change of wing motion patterns, a trait that likely alleviates the computational demand on flight control. This work uncovers key traits of hummingbird agility, which can also inform and inspire designs for next-generation agile aerial systems.
Description of the Data and file structure
The mat file contains data from two birds used in the experiments (bird_1 and bird_2)
tSH: contains the data on the relationship between light removal time instance and time to stop and hover.
- logitRegg: logistic regression optimized parameters and critical light removal time instance.
- linearModel: Linear fit model for light removal time instance and time to stop and hover for Category II and Category III demonstrations.
- data: Raw data of light removal time instance and time to stop and hover. [time in milliseconds]
hoverData: Wing kinematics data during hovering before the start of escape maneuvers
- LWstr: Left-wing stroke angle [degree]
- LWdev: Left-wing deviation angle [degree]
- LWstr: Left-wing pitch angle [degree]
- RWstr: Right-wing stroke angle [degree]
- RWdev: Right-wing deviation angle [degree]
- RWstr: Right-wing pitch angle [degree]
- t: normalized time [0,1] for wing beat cycle [time in seconds]
kinematics: Complete bird kinematics during escape maneuver (Forward: Bird pitch down to forward flight, Pd-F after reorientation, Category I and III; Stopping: Bird pitch up to Hover, Pu-H after reorientation)
- Wing: wing kinematic is in format (Stroke, Deviation, Pitch) [degree]
- Body: variable represent a vector in the global frame while variable_b represent a vector in the body fixed frame [velocity in m/s and angular velocity in deg/s]
- Beak: The angular velocity of the beak [degree/sec]
- time: time stamps for each trials [seconds]
- type: weather the trial is a case of Forward or stopping
- Point: Raw 3D digitized data [m]
intendedTraj: Kinematic data for estimated intended trajectory during escape maneuver
- Y_mean & Y_sd: mean and stand deviation for the estimated trajectory the variables in Y are defined in the description
- Time_Align: The time stamps for the aligned kinematics [ms]
- SegUp: The index of end of upstroke in the “Time_Align” variable
- SegDown: The index of end of downstroke in the “Time_Align” variable
- Id: The raw aligned and unalign kinematic data (the index of each variable is mentioned in “Description” variable)
- Group: ‘Align_All_Cases’ means both data from all the trials were used for the alignment
- GroupName: ‘All_Cases’ = All the trials
WMP_analysis: Data for Wing Motion Primitive analysis
- wingBeatDistFromHover: Statistical distance of each wing beat from hover wing beat estimate [probabilistic distance]
- WMPs: Wing motion primitives for hover(H), evasion(PuB) and reorientation(R)
- wingBeatWMP: WMP magnitude in each wingbeat of all the demonstrations [degree]
- crossCorr: Cross-correlation analysis data for pitching and rolling
- AngRateFit: Data for the relationship between WMP magnitude and angular rates [degree/sec]