Importation of plastic fragments into a seabird colony: accident or design, threat or benign?

Summary Plastic pollution affects marine ecosystems worldwide and poses risks for seabirds. Most recorded impacts on organisms are negative but, in some cases, the constructive use of plastic fragments or objects by birds has also been recorded. Small blue and green plastic fragments are found scattered among nests in a large (c.500,000 pairs) Sooty Tern Onychoprion fuscatus nesting colony on Bird Island, Seychelles. We investigated whether the fragments were being imported by the birds, and if so whether import was accidental or intentional. We found that Sooty Terns were the only seabird species to have plastic fragments in their nesting area and import of fragments varied seasonally and spatially. Throughout the colony, plastic fragments were imported during egg-laying, incubation, and chick-rearing, but import declined as chicks began to fledge. A part of the colony where all eggs were harvested for human consumption received more fragments than among undisturbed nests. We failed to find evidence of ingestion and excretion of fragments and suggest other avenues for investigation.

An ~1100 yr record of human and seabird occupation in the High Arctic inferred from pond sediments

Seabirds in the Canadian Arctic congregate in large colonies, producing oases of biological productivity and diversity in coastal regions. Here, we examined sterols, stanols, and stable isotopes (δ15N and δ13C) in three 14C-dated pond sediment cores near a large seabird colony and archaeological site on Devon Island (Nunavut, Canada), showing historical occupation by the seabirds and an ancient human (Thule or Norse) settlement over an ~1100 yr time period. Coprostanol in the sediment records captures the presence of humans at ca. 1150 CE, followed by their abandonment of the site by ca. 1300 CE. Increased seabird presence at this site after ca.1200 CE is indicated by increases in δ15N and cholesterol/sitosterol. Seabird population expansion is observed after ca. 1600 CE in δ15N and cholesterol/sitosterol profiles, coinciding with European whaling activities that expanded in the seventeenth through nineteenth centuries. Our study provides insights into human and seabird occupation in the High Arctic to inform archaeological and conservation efforts.

The Keepers of the Ghost Bird

This chapter focuses on the birds in Bermuda. Prior to 1600, it is estimated that half a million pairs of devil birds bred on Bermuda, making it, in essence, a gigantic seabird colony. The cedar trees that covered Bermuda were endemic and low-growing; they tilted in high winds, uprooting and leaving small cavities beneath. The birds used their black beaks, which ended in a graceful hook, to dig twelve-foot burrows beneath the trees, and used their webbed feet to push the dirt out behind them. The sailors called it the cahow after its sound. It would be centuries before it would emerge as a species of gadfly petrel — a sleek-bodied, hollow-boned soarer with three-foot-long, paddle-shaped wings. In 1906, Dr. Louis Mowbray, who would become the first director of the Bermuda Aquarium, found a live bird in a hole on one of the Castle Harbor Islands; he classified it as a Peale's petrel from New Zealand, blown off course. A decade elapsed before an ornithologist realized that Mowbray's live bird was actually the real thing: a Bermuda petrel.