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MEPS prepress abstract   -  DOI:

Desperate times call for desperate measures: non-food ingestion in starving seabirds

Lauren Roman, Scott Bryan, Natalie Bool, Leah Gustafson, Kathy Townsend

*Corresponding author:

ABSTRACT: Food deprivation may decrease selectivity in food choices, but can species cross a selectivity threshold whereby they ingest non-food (engaging in pica/lithophagia), and what are the implications? By examining carcasses of seabirds that ingested pumice of known provenance prior to death, we provide insights into whether wild animals starve because they have eaten non-food, or whether they eat non-food because they are starving. We investigated ingestion of pumice and plastic in carcasses of short-tailed shearwaters, Ardenna tenuirostris, following a significant starvation mortality event (wreck), during which millions of shearwaters died along the eastern Australian coastline in 2013. We found that 96.5% of 172 seabirds sampled had pumice or plastic in its stomach at the time of death. We used global location sensors (GLS) to track the 2013 shearwater migration and overlaid these tracks with the dispersing pumice raft from the 2012 eruption of the Havre underwater volcanic eruption. We determined that shearwaters in a starved state had ingested pumice 12-41 hours before death, indicating that starving or food-stressed seabirds exhibit reduced prey discrimination. The provenance of plastic was not known. Ingestion of non-food has serious implications for wildlife, particularly long-lived or migrating species. Additional risk to already nutritionally compromised animals includes dietary dilution, gastric foreign body obstruction and toxicity. With a projected increase in desperate times for wildlife, such as changing climate, marine pollution and over-exploitation of resources, this study has implications for the interaction of stressors, mass mortalities and exacerbation of existing threats to marine species.