Data from: drones as a tool to study and monitor endangered Grey Crowned Cranes (Balaerica regulorum): behavioural responses and recommended guidelines

Demmer, Carmen1 ; Demmer, Stuart2 ; McIntyre, Trevor1

Published Feb 28, 2024 on Dryad. https://doi.org/10.5061/dryad.tdz08kq59

Data files

Feb 28, 2024 version files 123.83 KB

0_Drone_deploy_distance_assessment.csv

18.76 KB
1_Method_comparrison.csv

28.88 KB
2_On-foot_method_assessment.csv

10.92 KB
3_Drone_method_assessment.csv

24.62 KB
4_1_Flock_on-foot_method_assessment.csv

6.76 KB
4_2_Flock_drone_method_assessment.csv

15.84 KB
5_Approach_angle.csv

9.04 KB
README.md

9.01 KB

Abstract

These data detail the results of an investigation into the impact of drones and on-foot approaches on the behaviour of the endangered Grey Crowned Crane (Balearica regulorum). In total, 313 drone flights and 56 on-foot approaches were conducted over three different Grey Crowned Crane group types - pairs (110 flights, 26 on-foot), families (66 flights, 7 on-foot), and flocks (110 flights, 23 on-foot). Response data describe the number of birds exhibiting a particular behaviour (1 - no behaviour change, 2 - heads raised to observe surroundings, 3 - wings raised, 4 -moving away, and 5 - flying away) based on a photograph taken during the approach. Predictor data include the distance between the drone or on-foot observer and the bird grouping and a description of the group type. The number of individuals in the group can be inferred from the response data.

README: Data from: drones as a tool to study and monitor endangered Grey Crowned Cranes (Balaerica regulorum): behavioural responses and recommended guidelines

This README file was generated on 2024-02-27 by Stuart Demmer.

GENERAL INFORMATION

Title of Dataset: Drones as a tool to study and monitor endangered Grey Crowned Cranes (Balearica regulorum): Behavioural responses and recommended guidelines
Author Information
A. Principal Investigator Contact Information
Name: Carmen Rosa Demmer
Institution: University of South Africa
Address: Howick, KZN South Africa
Email: carmenrdemmer@gmail.com

B. Associate Contact Information
Name: Stuart Demmer
Institution: NA
Address: Howick, KZN South Africa
Email: stuart.demmer@gmail.com

B. Supervisor Contact Information
Name: Trevor McIntyre
Institution: University of South Africa
Address: Pretoria, GAU South Africa
Email: mcintt@unisa.ac.za
Date of data collection (single date, range, approximate date): 2022-2023
Geographic location of data collection: Southern Drakensberg, KwaZulu-Natal, South Africa
Information about funding sources that supported the collection of the data: No formal funding

SHARING/ACCESS INFORMATION

Licenses/restrictions placed on the data: CC0 1.0 Universal (CC0 1.0) Public Domain
Links to publications that cite or use the data:

Demmer, C. R., Demmer, S., & McIntyre, T. (2024). rones as a tool to study and monitor endangered Grey Crowned Cranes (Balearica regulorum): Behavioural responses and recommended guidelines. Ecology and Evolution. https://doi.org/10.1002/ece3.10990

Links to other publicly accessible locations of the data: None
Links/relationships to ancillary data sets: None
Was data derived from another source? No
A. If yes, list source(s): NA
Recommended citation for this dataset:

Demmer, C. R., Demmer, S., & McIntyre, T. (2024). Data from: Drones as a tool to study and monitor endangered Grey Crowned Cranes (Balearica regulorum): Behavioural responses and recommended guidelines. Dryad Digital Repository. https://doi.org/10.5061/dryad.tdz08kq59

DATA & FILE OVERVIEW

File List:

A) 0_Drone_deploy_distance_assessment.csv
B) 1_Method_comparrison.csv
C) 2_On-foot_method_assessment.csv
D) 3_Drone_method_assessment.csv
E) 4_1_Flock_on-foot_method_assessment.csv
F) 4_2_Flock_drone_method_assessment.csv
G) 5_Approach_angle.csv

Relationship between files, if important: None
Additional related data collected that was not included in the current data package: None
Are there multiple versions of the dataset? No
A. If yes, name of file(s) that was updated: NA
i. Why was the file updated? NA
ii. When was the file updated? NA

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DATA-SPECIFIC INFORMATION FOR: 0_Drone_deploy_distance_assessment.csv

Number of variables: 3
Number of cases/rows: 516
Variable List:

* behaviour_type: type of behaviour displayed

* proportion: proportion of birds in the grouping that displayed the behaviour type

* drone_deploy_distance: distance from drone deployment site to bird grouping (in meters)

Missing data codes: None
Specialized formats or other abbreviations used: None

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DATA-SPECIFIC INFORMATION FOR: 1_Method_comparrison.csv

These are the data used to determine the average distance at which observations were able to be made between two monitoring methods; dones and on-foot approaches.

Number of variables: 5
Number of cases/rows: 804
Variable List:

* subject_grouping_id: id of bird grouping

* group_type: bird grouping type

* monitoring_method: type of monitoring method used when approaching the bird groupings

* behaviour_type: type of behaviour displayed by the grouping

* distance: distance at which the behaviour type was displayed (in meters)

Missing data codes: NA (data not available)
Specialized formats or other abbreviations used: None

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DATA-SPECIFIC INFORMATION FOR: 2_On-foot_method_assessment.csv

These are the data used to determine the distance at which different behaviours were displayed by the birds when approached on-foot.

Number of variables: 6
Number of cases/rows: 288
Variable List:

* subject_grouping_id: id of bird grouping

* group_type: type of bird grouping

* monitoring_method: type of monitoring method used

* behaviour_type: type of behaviour exhibited by a proportion of the birds in the grouping at the given distance

* proportion: proportion of birds in the grouping exhibiting the behaviour type

* distance: distance of the observer to the bird grouping where the observation was made (in meters)

Missing data codes: NA (data not applicable)
Specialized formats or other abbreviations used: None

#########################################################################

DATA-SPECIFIC INFORMATION FOR: 3_Drone_method_assessment.csv

These are the data used to determine the distance at which different behaviours were displayed by the birds when approached by a drone.

Number of variables: 5
Number of cases/rows: 516
Variable List:

* group_type: type of bird grouping

* monitoring_method: type of monitoring method used

* behaviour_type: type of behaviour exhibited by a proportion of the birds in the grouping at the given distance

* proportion: proportion of birds in the grouping exhibiting the behaviour type

* distance: distance of the drone to the bird grouping where the observation was made (in meters)

Missing data codes: None
Specialized formats or other abbreviations used: None

#########################################################################

DATA-SPECIFIC INFORMATION FOR: 4_1_Flock_on-foot_method_assessment.csv

These are the data used to determine the change in behavioural response by grey crowned crane flocks of different sizes to on-foot approaches.

Number of variables: 6
Number of cases/rows: 158
Variable List:

* group_type: type of bird grouping

* monitoring_method: type of monitoring method used

* behaviour_type: type of behaviour exhibited by a proportion of the birds in the grouping at the given distance

* flock_size: the total number of birds in the flock

* proportion: proportion of birds in the grouping exhibiting the behaviour type

* distance: distance of the drone to the bird grouping where the observation was made (in meters)

Missing data codes: None
Specialized formats or other abbreviations used: None

#########################################################################

DATA-SPECIFIC INFORMATION FOR: 4_2_Flock_drone_method_assessment.csv

These are the data used to determine the change in behavioural response by grey crowned crane flocks of different sizes to drone approaches.

Number of variables: 6
Number of cases/rows: 286
Variable List:

* group_type: type of bird grouping

* monitoring_method: type of monitoring method used

* behaviour_type: type of behaviour exhibited by a proportion of the birds in the grouping at the given distance

* flock_size: the total number of birds in the flock

* proportion: proportion of birds in the grouping exhibiting the behaviour type

* distance: distance of the drone to the bird grouping where the observation was made (in meters)

Missing data codes: None
Specialized formats or other abbreviations used: None

#########################################################################

DATA-SPECIFIC INFORMATION FOR: 5_Approach_angle.csv

These are the data used to assess the reponse of breeding grey crowned crane parents with offspring (either nesting or with hatchlings) to drone approaches from two angles.

Number of variables: 4
Number of cases/rows: 315
Variable List:

* nest_site_id: the ID of the nest site being measured

* breeding_stage: the stage of nesting, either before ("During nesting") or after eggs are hatched ("After nesting")

* approach_angle: the angle at which the drone was flown while approaching the nest (vertical = approx. 90°, diagonal = approx. 45°)

* disturbance_type: the level of disturbance experienced by the grouping because of the approach (1 = minor - no response, looking , 2 = modertate - standing, wings raised or walking away, 3 = major flying away)

Missing data codes: None
Specialized formats or other abbreviations used: None

Methods

Experiment 1: Monitoring method comparison experiment

Trial observations included recording the behavioural cues of GCC groupings (pairs, families, and flocks) in response to either of the two monitoring methods (on-foot, drone) across various distances and flight heights. Behavioural cues were categorised as follows: no behaviour change (1), heads raised to observe surroundings (2), wings raised (3), moving away (4), and flying away (5) (Figure 1). All trial observations were undertaken by the same observer and care was taken to wear similarly coloured clothing for each of the trials.

On-foot monitoring

Upon locating a GCC grouping, the observer approached the group at a constant walking speed of approximately 1 m.s^-1, making a reasonable effort not to disturb the grouping (e.g., avoiding noises and sudden movements). Observations were noted at the start of each trial, every 10– 15^th step thereafter, and again if any change in GCC behaviour was observed. Each observation included measuring the distance between the observer and the grouping using a range finder (Vortex Crossfire HD LRF-CF1400 Rangefinder) and taking a photograph (Nikon D7200 with 100-400mm Sigma lens) of the group which enabled post hoc behaviour coding. Observations were recorded until groupings displayed a type 5 response (flying away).

Drone methodology

The drone pilot positioned herself at least 100 m from GCC groupings before drone take-off and at a similar altitude to the GCC grouping. On rare occasions the pilot found it practically impossible to position herself at 100 m, but all drone experimental approaches were conducted from distances of at least 80 m from the GCC groupings. The drone was deployed from the pilot’s location to a randomly pre-selected flight height (10, 30, 50, or 70 m above the deploy point), then flown over the grouping at the selected flight height at a speed of 5 m.s^-1 with video recording activated to facilitate post hoc behaviour coding. After reaching the grouping, the drone was flown ± 80 m beyond the grouping and then returned to the deploy point to avoid flying over the grouping during the return flight. All drone flights were conducted using a standard Mavic Air 2S drone (DJI Technology Co., Shenzhen, China) (595 g, 1-inch 20MP sensor, 8× zoom, 65dB low noise propeller).

The precise height of the drone above the grouping was difficult to determine in situ as the drone only reports flight height relative to the take-off point. The flight height above GCC groupings was therefore determined post-hoc by extracting altitude values for the drone deployment and subject locations from a high-resolution (± 2 m) digital elevation model of the study area using the coordinates as recorded by the drone’s Global Positioning System.

Data collection from each grouping continued until a maximum of four trials had been recorded (with a 10-minute interval to allow birds to return to their prior behaviour) or until the subjects exhibited a type 5 response. As a precaution, the drone was always flown manually to allow the pilot to easily manoeuvre and control the drone to avoid any potentially aggressive behaviour from the target or non-target species in the study area. Each site was scanned for non-target species using binoculars before beginning a drone mission. Whilst in flight, the pilot remained aware of any new individuals of the target or non-target species entering the site. As far as practically possible, we avoided flights over any non-target species. If any non-target species displayed discomfort in the presence of the drone, the pilot avoided flying whilst that species was near the flight route; and if territorial, future flights at that site were terminated.

Post-hoc behavioural coding

Video and photo footage were assessed post hoc by a single person. Each photo taken during the on-foot monitoring experiment was considered an observation. From each video recorded during the drone monitoring experiment the frame directly above the grouping was extracted and used as the observation. If birds responded with a type 5 response before the drone reached the grouping, the frame closest in time was used to determine the position of the drone whilst focusing on the initiated flight response of the grouping. For each observation, each bird’s behaviour was identified and the total number of subjects displaying each of the five behaviours was recorded for each observation.

Experiment 2: Nesting approach experiment

We identified breeding behavioural cues consisting primarily of a lone crane foraging close to a water body or wetland. A drone flight was initiated to locate either a nest site or the breeding birds themselves. If either of these were located, we considered it an observation. At ± 20 m from the subject, the drone was lowered to a flight height of ± 20 m. The drone was then manoeuvred towards the subjects either by flying diagonally (an angle of ± 45°) or vertically (flying horizontally until above the subjects and then descending at an angle of ± 90°), slowly descending until ± 7.5 m from the subjects. Because of the limitations of determining distances in situ via the drone the distances given here are approximate. Video recording was enabled throughout the approach to facilitate post hoc behavioural coding as follows; (1) little disturbance (either looking, remaining sitting, holding ground, or standing up), (2) moderate disturbance (raising wings, walking, or running away from offspring), or (3) major disturbance (flying away from offspring).