DOI: 10.5061/dryad.jh9w0vtd7
title: Satellite telemetry data for Egyptian Geese in southern Africa

description: This archive contains all currently available satellite GPS telemetry data
 for Egyptian Geese in southern Africa over the period from 2008 to 2016.
 The data were collected with two primary aims: (1) to understand the
 movement ecology of this species; (2) to better evaluate the potential
 role of Egyptian Geese in spreading avian influenza in southern Africa.
 Data colelction was undertaken in several phases. The first phase focused
 on just three sites (Manyame, Barberspan, Strandfontein) and occurred at
 the same time as a series of extensive bird counts and captures. Birds
 captured during this period were tested for avian influenza. We also
 undertook an extensive colour-ringing exercise on Egyptian Geese during
 the first phase. The second phase of the program involved extending our
 activities to some new locations (Voelvlei, Jozini) to test specific
 hypotheses about movement and the timing of moult, and to improve the
 generality of our findings. The third phase involved a translocation
 experiment in which six birds were moved from Barberspan to Strandfontein.
 The data have been analysed and published in a number of different venues
 and publications, as listed in the associated metadata.
description: We tagged birds with satellite GPS PTTs (Microwave Telemetry) at
 three different latitudes in areas located along a north-south gradient
 running from Lake Manyame in Zimbabwe (-17.846S, 30.601E; near Harare)
 through Barberspan (-26.590S, 25.589E; NW Province of South Africa) to
 Strandfontein (-34.086S,18.516E; on the edge of False Bay, near Cape
 Town). These data were later complemented with smaller numbers of tagged
 birds at Voelvlei (-33.337S, 19.036; Western Cape, north of Cape Town) and
 Jozini Dam (-27.417S, 31.967E; Kwazulu-Natal, West of St. Lucia). The
 tagging locations span 17 degrees of latitude (approximately -17 to -34
 degrees S) and the ends of the transect are situated approximately 2,200
 kilometres apart. Lake Manyame and Jozini Dam fall in a typical summer
 rainfall region; Barberspan receives variable but dominantly summer
 rainfall; and Strandfontein and Voelvlei are in South Africa’s winter
 rainfall region.  Birds were captured at each study
 site using walk-in traps, mist nets, and a cannon net. We tagged
 individual birds from different traps and typically spread captures over
 several days to ensure that two birds from the same flock were not tagged.
 We deliberately selected known wing feather moulting sites for the study
 and tried where possible to place transmitters on adult birds that had
 recently moulted but had not completely regrown their wing feathers, for
 three main reasons: (1) so that we would know definitively that the bird
 was tagged at a moulting site; (2) birds that moult in a given location
 are more likely to be part of a local population, and hence to behave
 typically for that region, rather then being transient, lost, or vagrant
 individuals; and (3) since these birds do not moult their back feathers
 until the following year, tagging recently moulted birds extends the time
 until potential regrowth of trimmed back feathers over the solar panel of
 the PTT.  Transmitters were attached to birds using a
 backpack harness made out of teflon ribbon, as described by Cumming
 & Ndlovu. We used 30g transmitters for Egyptian Geese (mean adult
 weight of tracked birds 2299g, standard deviation 432.46g). Transmitters
 were set to capture GPS location data every two hours (30g PTTs) and
 transmit data to the Argos satellite every 3 days. Six of the birds in the
 dataset were captured at Barberspan and translocated to Strandfontein
 before release, as described in the Diversity & Distributions
 paper to which this archive is linked. This experiment was designed to
 shed light on the navigation capacity of Egyptian Geese.
 The data given here are unprocessed apart from conversion from
 the Argos format to a more readable format, using Microwave
 Telemetry's conversion software; and splitting any files from the
 same transmitter where they were collected from different birds. The
 associated R code on Zenodo repeats the analyses given in the Diversity
 & Distributions paper.
description: The data are high-quality GPS fixes with a typical accuracy of
 10-15m. In several cases there are gaps in transmissions as a result of
 transmitters not recording for periods of up to several months, then
 resuming (we assume, due to feather covering up solar panels and/or birds
 moving into conditions where solar panels were more exposed). Note that
 the data set also includes several cases in which the PTT was removed from
 one bird and placed on another. We have divided these into separate data
 sets as explained in the relevant papers.