Defining marine habitat use by seabirds

Overview

Aotearoa New Zealand waters support the greatest diversity of seabirds on Earth, including rare and endangered species, such as albatrosses, petrels and shearwaters. It is critical that we know the number of birds, where they live and their migration patterns. 

Using boats to survey bird populations and collect detailed data about seabird distributions is extremely expensive. We investigated whether cheaper, modelling methods can produce accurate estimates of which areas of the ocean are important for seabirds and how many there are. Our model uses information about the types of environments where seabirds live. For example, we know that some species prefer coastal habitats and others prefer ocean habitats. We compared these species-specific relative environmental suitability models with models that are built on location data from seabird sightings or electronic tags.

In preparation for model development, we processed large volumes of seabird tracking data. Campbell albatrosses are a New Zealand endemic species that breeds only at Campbell Island. We have discovered that the range of their migration is much further than we thought. Some migrate to South America following breeding, while others remain close to New Zealand or Australia. This new information about their migration patterns has significant implications for assessing the risk of fishing activity to this species. For example, birds choosing to migrate to South America will be exposed to different levels of fishing risk compared to birds remaining in Australasia.

Our novel approach has the potential to produce new information about how seabirds use the marine environment. This could help gauge how threats in the marine environment may affect these high-profile species and inform New Zealand Government policies.