Prevalence and composition of fishing gear debris in the nests of northern gannets (Morus bassanus) are related to fishing effort

Distribution and abundance of baling twine in the landscape near Osprey (<em>Pandion haliaetus</em>) nests: implications for nestling entanglement

“…We lacked information on the age of nests, but it appeared that larger nests, which were presumably older, contained more twine; however, the limited sample of seven nests made this inference tentative. Although we found a variety of anthropogenic materials in nests, the largest component was baling twine, and such selectivity has been noted in a diversity of bird species from seabirds to raptors to passerines (e.g., Antczak et al 2010;Sergio et al 2011;votier et al 2011;Bond et al 2012). Whereas the cost of using baling twine in Osprey nests was clear, any potential benefits have yet to be determined (e.g., conspecific signaling; Sergio et al 2011).…”

“…Similar variation was reported in the mass of plastics found in five nests constructed by Northern Gannets (votier et al 2011). Several proximate factors have contributed to the extent that artificial materials are used in nest construction or as nest adornments: abundance in the environment (Blem et al 2002;Bond et al 2012), age of the nest (votier et al 2011;Bond et al 2012), and age of the nest builder (Sergio et al 2011). On the yellowstone River, no relationship existed between the amount of twine found in the landscape and the amount found in Osprey nests.…”

“…We are also identifying what we believe are significant sources of the twine that ends up along roads (e.g., feedlots). Polypropylene baling twine degrades slowly and clean-up efforts along roads and in pastures and feedlots will have to be coordinated for decades to reduce dangers to Ospreys (see also Ryan et al 2009;Bond et al 2012). It appears that farmers and ranchers are slowly switching from using twine to bale hay and straw to using plastic netting or wraps.…”

“…While driving between nests, we often observed remnants of baling twine along the shoulders of secondary roads. The prevalence of plastic string, rope, and twine in the environment surrounding nests has been cited as a reason for their occurrence in nests (Blem et al 2002;Antczak et al 2010;Bond et al 2012), and our observations prompted us to investigate the abundance of discarded baling twine in the landscape surrounding Osprey nests. Our objectives were to estimate and com-ThE cANADIAN pare the amount of twine along roads near Osprey nests across a gradient from rural to urban landscapes and to assess the relation between the presence of twine in nests and the amount of twine found along roads near nests.…”

“…Because plastics degrade slowly, using the percentage of nests containing plastics as an index of their abundance in the environment over time requires both a constant search effort and knowledge of bird population trends (Ryan et al 2009). Moreover, the presence of plastics in large, long-lasting nests suggests that such an index is best considered over decades rather than years (Bond et al 2012). Although some individuals within a species benefit by signaling conspecifics through the use of artificial nesting materials (hansell 2000), plastic rope and twine present a potential risk of nestling and adult entanglement.…”