# Environmental Features Associated With At‐Sea Sightings of Snow Petrel Pagodroma nivea in East Antarctica

## TL;DR

This study identifies environmental factors linked to Snow Petrel sightings in East Antarctica and compares data collection methods for modeling their presence.

## Contribution

The study introduces a comparison of data recording methods for modeling Snow Petrel presence in East Antarctica.

## Key findings

- Snow Petrel presence is associated with shallower bathymetry, increasing sea-ice coverage, decreasing sea-surface height, and increasing wind speed.
- Effort-quantified models were more robust than presence/absence models, showing higher deviance explained and narrower confidence intervals.
- Environmental associations may reflect foraging strategies targeting biologically productive areas in the Southern Ocean.

## Abstract

Over the last 70 years, seabird populations have declined by up to 70%, and represent the most endangered group of birds globally. When compared to other seabird species, there is little known about the Snow Petrel (
Pagodroma nivea
) and its marine habitat use—especially in East Antarctica. To better understand what drives Snow Petrel presence within this region, we modeled vessel‐based observations of the Snow Petrel against remotely sensed environmental data using binomial generalized additive models (GAMs). Throughout the 16‐year study period (1991–2006), Snow Petrel presence was associated with areas exhibiting shallower bathymetry, increasing sea‐ice coverage, decreasing sea‐surface height, and increasing wind speed. We then used a subset of the Snow Petrel data to generate a population density map and compare model outputs when data recording methods differ. Specifically, we tested how outputs change when inputs are binomial (presence/absence) versus when inputs include count and effort data. The outputs from both effort‐quantified and presence/absence models identified similar environmental drivers of Snow Petrel presence. However, the effort‐quantified models were more robust, yielding higher deviance explained values and narrower confidence intervals around the environmental variables associated with Snow Petrel presence. Snow Petrel interactions with the tested environmental variables may be driven by associated biological processes—specifically, foraging strategies that target niche areas of high biological productivity in the Southern Ocean. Our study provides an important baseline to compare the likely future distribution of Snow Petrels under different climate change scenarios.

Over the last 70 years, seabird populations have declined by up to 70% across the globe. Compared to other seabirds, little is known about Snow Petrels and their marine habitat use—especially in East Antarctica. This study addresses the former knowledge gap while simultaneously comparing how outputs differ when data collection methods vary.