Data from: Different migration patterns of Wahlberg’s Eagles Hieraaetus wahlbergi across Africa
Data files
Oct 01, 2024 version files 108 MB
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README.md
2.73 KB
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WAEA_jab.csv
108 MB
Abstract
Intra-Africa movements of most African migratory birds remain an enigma. We describe the migrations of Wahlberg’s Eagle Hieraaetus wahlbergi using GPS-GSM transmitters on adult eagles in their South African (n=3) and Kenyan (n=7) breeding areas between 2018-2022. The dataset included 57 migratory tracks, 29 post-breeding and 28 pre-breeding. We found long-distance (LDMs; from South Africa) and short-distance (SDMs; from Kenya) migratory populations using common non-breeding areas centered in the Sudans and Central African Republic. The timing of annual phases was similar, but LDMs departed on their pre-breeding migration on average later than SDMs (13 Aug vs 31 July) and arrived later on their breeding grounds (13 Sep vs 10 Aug). Conversely, the average departure date on the post-breeding migration was 4 April for SDM and 23 March for LDMs. LDMs spent significantly less time of the year than SDMs on breeding grounds (44% vs 57%), and slightly but not significantly more time (40% vs 38%) on non-breeding areas. The post-breeding migration distance was on average 3413.9 ± 170.9 km for LDMs and 491.9 ± 158.5 km for SDMs. At non-breeding areas, LDMs reached more northerly latitudes than SDMs, increasing the pre-breeding migration distance to 4495.9 ± 372.5 km for LDMs versus 1701.9 ± 167.3 for SDMs. Daily flight distances back to the breeding areas averaged 153.4 ± 130.3 km for LDMs and 167.4 ± 122.3 km for SDMs and to non-breeding areas were shorter for SDMs (124.8 ± 113.0 km) than LDMs (178.0 ± 134.4 km). Migration speed was similar across populations and for pre- and post-breeding migrations. LDMs used more stopover days than SDMs. We conclude that Wahlberg’s Eagles from different parts of Africa have adapted their migration to differences in timing of the breeding season, distance of travel, and resources in the landscapes encountered during migration.
README: Different migration patterns of Wahlberg’s Eagles Hieraaetus wahlbergi across Africa
https://doi.org/10.5061/dryad.ffbg79d47
Description of the data and file structure
Data from: Different migration patterns of Wahlberg’s Eagles Hieraaetus wahlbergi across Africa
Access this dataset on Dryad: https://doi.org/10.5061/dryad.ffbg79d47
This dataset was downloaded, with permission from the researchers, from Movebank. Here we provide only the columns useful for analysis. Due to the number of analyses performed in the manuscripts, we only provide the raw data here.
Column heading description:
barometric height: Altitude estimated by a barometric pressure sensor on the tag.
Units: meters
battery charge percent: The battery charge as a percentage of full charge.
Units: percent
GPS fix type: The type of GPS fix.
Allowed values are 1 = no fix;
2 = 2D fix (altitude typically not valid);
3 = 3D fix (altitude typically valid).
GPS HDOP: Horizontal dilution of precision provided by the GPS.
Units: unitless
GPS maximum signal strength: The signal reception strength of the strongest GPS satellite of those used to calculate the location estimate.
Units: dBm
GPS satellite count: The number of GPS satellites used to estimate the location.
Units: count
GPS time to fix: The time required to obtain the GPS location fix.
Units: seconds
ground speed: The estimated ground speed provided by the sensor or calculated between consecutive locations.
Units: m/s
heading: The direction in which the tag is moving, in decimal degrees clockwise from north, as provided by the sensor or calculated between consecutive locations. Values range from 0-360: 0 = north, 90 = east, 180 = south, 270 = west.
Units: degrees clockwise from north
height above mean sea level: The estimated height of the tag above mean sea level, typically estimated by the tag. If altitudes are calculated as height above an ellipsoid, use 'height above ellipsoid'.
Units: meters
location lat: The geographic latitude of the location as estimated by the sensor.
Units: decimal degrees, WGS84 reference system
location long: The geographic longitude of the location as estimated by the sensor. Positive values are east of the Greenwich Meridian, negative values are west of it.
Units: decimal degrees, WGS84 reference system
timestamp: The date and time corresponding to a sensor measurement or an estimate derived from sensor measurements.
Format: yyyy-MM-dd HH:mm:ss.SSS
Units: UTC
trackId: Individual bird identifier.
timezone: Time zone of the location.