10.5061/DRYAD.CC2FQZ65T
Schultz, Hendrik
University of Auckland
Chang, Kevin
University of Auckland
Bury, Sarah
National Institute of Water and Atmospheric Research
Gaskett, Anne
University of Auckland
Dennis, Todd
Fiji National University
Ismar-Rebitz, Stefanie
GEOMAR Helmholtz Centre for Ocean Research Kiel
Southey, Ian
Birds New Zealand, South Auckland, NZ
Hohnhold, Rebecca
University of Auckland
Millar, Craig
The University of Auckland
Sex-specific foraging of an apex predator puts females at risk of
human-wildlife conflict
Dryad
dataset
2021
GPS tracking
brown skua
facultative scavenger
Movement and foraging ecology
New Zealand International Doctoral Research Scholarship*
N/A
Birds New Zealand Research Fund*
N/A
James Sharon Watson Conservation Trust*
N/A
University of Auckland
https://ror.org/03b94tp07
N/A
New Zealand International Doctoral Research Scholarship
Birds New Zealand Research Fund
James Sharon Watson Conservation Trust
2021-04-17T00:00:00Z
2021-04-17T00:00:00Z
en
3785977 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Urbanisation and anthropogenic alteration of ecosystems has led to
conflict between humans and wildlife. Such conflict is often observed in
apex predators. Although human-wildlife conflict has been extensively
studied, male/female differences in behaviour are rarely considered. We
investigated male/female differences in foraging behaviour of the
predatory/scavenging brown skua Catharacta antarctica lonnbergi breeding
on a New Zealand island nature reserve in proximity to farmland. These
skuas are subject to culling, when perceived as a threat to livestock. As
part of a long-term ecological study, we used high-resolution Global
Positioning System (GPS) devices to characterise the space-use of foraging
brown skuas. We also analysed stable isotopes of carbon (δ13C) and
nitrogen (δ15N) from modern and archived blood samples to investigate
possible changes in diet over the past ~30 years. Analysis of 100 GPS
tracks collected from 2014-16 demonstrated that males and females
consistently visited different habitats. Males spent most of their time
close to their breeding territory on the island nature reserve and females
frequently visited a farmed island approximately two kilometres away.
Consistent with this finding, we show that male and female skuas also
differed markedly in their diets: males specialised on burrow-nesting
white-faced storm petrels Pelagodroma marina (80%) with only a small
proportion of sheep remains Ovis aries (<6%) contributing to their
diet. In contrast, female diet comprised 27% white-faced storm petrels,
other seabirds (18%), and a relatively large proportion of sheep remains
(47%). Further, our data (186 blood samples from 122 individuals) show
that this male / female difference in diet has persisted at least since
1987. Because females fed disproportionally on sheep remains, they may be
more vulnerable to being culled by farmers. Importantly, our case study
suggests that intersexual differences in diet and foraging patterns can
have major implications for the reproduction and survival of apex
predators that interact with farming. We strongly suggest that intersexual
differences in behaviour should be considered when investigating
human-wildlife conflicts.
See published article.
Readme files – there are three archived datasets associated with this
publication. 01. Skua blood stable isotope data The first file contains
stable isotope data (d13C and d15N) from whole blood of brown skuas
(Catharacta antarctica lonnbergi) breeding on the Chatham Islands
(filename '01. Skua blood isotopes Schultz et al | J Anim
Ecol.xlsx'). The file contains the following information / columns:
SampleID Unique identifier for each blood sample Species Species
identifier (here brown skua) Tissue Type of tissue analysed (here blood
only) BirdID Unique identifier for each bird Sex Gender information Year
Sampling year Origin Indicates whether samples are modern (2014-16) or
archived (1987-1993) d15N Stable nitrogen isotope values d13C Stable
carbon isotope values d13CadjSuess Stable carbon isotope values adjusted
for the Suess effect 02. Prey muscle isotope data A second dataset
includes stable isotope values (d13C and d15N) from muscle tissue of
respective prey species (filename '02. Prey isotopes Schultz et al |
J Anim Ecol.xlsx'). The file contains the following information /
columns: SampleID Unique identifier for each blood sample Species Species
identifier Atomic.wt.C.N.ratio Atomic C:N ratio Mass.C.N.ratio Mass C:N
ratio d13C Stable carbon isotope values lipid.corrected.d13C Stable carbon
isotope values, mathematically corrected for lipid content d15N Stable
nitrogen isotope values Concdepd13C Concentration dependence for stable
carbon Concdepd15N Concentration dependence for stable nitrogen 03. Skua
GPS tracking data A third file includes GPS tracking data of brown skua
collected during the study period (2014-16) (filename '03. Skua GPS
Schultz et al | J Anim Ecol.xlsx'). The file contains the following
information / columns: BirdID Unique identifier for each bird Sex Gender
information NestID Unique identifier for each nest site NestDistanceHarv
Great Circle Distance from each respective location to the nest site Year
Sampling year Latitude Latitude in World Geodetic System (WGS84) format
Longitude Longitude in WGS 1984 format in World Geodetic System (WGS84)
format POINTX_CITM Longitude in Chatham Islands Transverse Mercator
projection POINTY_CITM Latitude in Chatham Islands Transverse Mercator
projection TripID Unique identifier for each trip (i.e. series of
consecutive locations outside a radius of 100m around the nest site)