This study investigated the foraging niche of dimorphic males and females Westland petrel during the chick-rearing period. At-sea movements were recorded with GPS, behaviours and foraging behaviour were recorded with accelerometers, and trophic niche was inferred with stable isotopes (carbon, nitrogen). Altogether, these fine-scale data allowed to look at the foraging niche used by males and females.

Individuals were caught in accessible burrow nests (one individual per nest), weighed and equipped with data loggers. Then, the occupancy of these nests was checked until the return of the equipped individuals. At recapture, the data loggers were retrieved, and the individual weighed again, morphometrics and blood sample taken (whole blood stored in 70% ethanol, for stable isotopes analysis and genetic sexing).

The metada from the birds are provided in the uploaded file “Westland petrels individuals metadata”, and the parameters of the tracks in the file “Westland petrel tracks parameters”. The way the combined GPS and accelerometer data were analysed is described in the uploaded file “GPS and accelerometer data code”.