Intraspecific Variation in Plastic Ingestion by Seabirds and the Flux of Plastic Through Seabird Populations

Patterns of intraspecific variability of ingested plastic loads in seabirds were examined for species collected off southern Africa.The incidence of plastic pollution was shown to be increasing during the 1980s.Both large-and small-scale geographic variation in plastic loads occurred as a function of variable plastic density in the environment.Intergenerational transfer of plastic particles was identified as an important pathway for plastic flow in those species that accumulate plastic particles and feed their chicks by regurgitation.This pathway can account for higher plastic loads in nonbreeders and failed breeders than in birds that breed successfully, and such results need not indicate adverse effects from plastic ingestion.Intergenerational transfer resulted in annual cycling of plastic loads in successfully breeding birds.In species that do not regurgitate indigestible stomach contents, immature birds have the largest plastic loads and are most likely to exhibit adverse effects from plastic ingestion.