Southern Influx of the Pantropical Bulwer's Petrel Bulweria bulwerii into the Tasman Sea

Seabirds exploit marine habitats for resources, responding to many complex environmental signals that ultimately drive their distributions. Occasionally, influxes of seabird species to regions outside their normal range occur and determining the drivers of these patterns can aid in understanding their ecology and their conservation. I documented five birdwatching observations of Bulwer’s Petrel Bulweria bulwerii in the Tasman Sea between 24 January and 08 March 2020, roughly 2000 km south of their core range. Based on demographic, environmental, and anecdotal observations of seabirds, cetaceans, and bait fish, I suggest that the influx was most likely resource-driven, rather than accidental, age-related, or directly linked to adverse weather. Increasingly frequent observations of Bulwer’s Petrel off eastern Australia may also indicate a southward distributional shift in this pantropical seabird, and monitoring of this potential shift will depend on the documentation of further observations.