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

Abstract

Seacor, Renee, Kayhan Ostovar, and Marco Restani. 2014. Distribution and abundance of baling twine in the landscape near Osprey (Pandion haliaetus) nests: implications for nestling entanglement. canadian Field-Naturalist 128(2): 173-178.Polypropylene baling twine used by Ospreys (Pandion haliaetus) during nest construction creates a risk of entanglement for nestlings and adults on the yellowstone River, Montana. In 2013, we evaluated the abundance of twine in 2-km-radius buffer zones centred on 38 nests for three categories of road density. We found more twine per kilometre along roads in low (n = 19) and moderate (n = 13) road density nest buffer zones than in high road density nest buffer zones (n = 6). The estimated total amount of twine found along roads in nest buffer zones ranged from 0 to 2602 m and did not differ among road density strata. The percentage of Osprey nests containing twine was highest in low (63.2%) and moderate (61.5%) road density nest buffer zones and lowest (33.3%) in high road density buffer zones, which reflected a gradient from rural and suburban to urban landscapes. The estimated total amount of twine within a nest buffer zone did not predict whether a nest contained twine. The amount of twine found in seven nests destroyed by wind or power company personnel ranged from 0 to 206 m and was not correlated with the amount of twine found in their buffer zones. During the 2012 and 2013 breeding seasons, four of 120 nestlings (3.3%) became entangled in twine: two were cut free and fledged normally, one died, and one was euthanized. The abundance of twine in the environment surrounding nests and its slow rate of biodegradation mean that vigilance by citizen scientist nest monitors and assistance from power companies are the only short-term solution to reducing mortality resulting from entanglement.

The use of anthropogenic debris as nesting material by the greater thornbird, an inland–wetland-associated bird of South America

“…Filaments of plastics (thread, rope, fishing line, string) were frequently recorded in some nests, such as numbers 1, 3, and 7 (A and B groups; Table 1). These elements are particularly prone to cause entanglement of birds inside the nest and have been shown to lead to injuries or mortality in other species (Seacor et al 2014;Votier et al 2011). Although none of the nests studied here contained entangled fledglings, we suppose that the same risk exists for birds in freshwater (Blettler et al 2019) or terrestrial environments.…”

“…On the other hand, the use of plastic materials has evident negative consequences such as entanglement inside the nest, as well as the yet little-known reduction in bird fitness (Seacor et al 2014). How potential benefits balance the entanglement, ingestion, and toxin hazards of plastic nest materials is still unknown.…”

Factors determining the occurrence of anthropogenic materials in nests of the white stork Ciconia ciconia

“…Plastic string, fishing nets, and angling gear are resistant materials occurring in the sea (far from nest sites) as well in the nest (collected by adults). These items often cause entanglement, leading to mortality or injuries (Baker et al 2002 ; Seacor et al 2014 ). Entanglement has been recorded in 25% of 312 studied seabird species (Gall and Thompson 2015 ).…”

“…plastic strings, foil) is collected from agricultural lands as nesting material and incorporated into nests (Tryjanowski et al 2006 ). Plastic string is one of the most common anthropogenic materials used by terrestrial species as nesting material (Antczak et al 2010 ; Seacor et al 2014 ). This material has been commonly used in Polish agriculture since 1982 for tying, e.g.…”

Golden Eagle Preys upon Fledgling Osprey in Montana

“…I had banded the brood of three nestlings on 15 July 2014 and returned to the site because volunteer nest monitors were concerned that one of the nestlings had become entangled in baling twine. Twine entangled an estimated 3.3% of Osprey nestlings within the Yellowstone River watershed in 2012-2013 (Seacor et al 2014), so their concern was warranted. The monitors reported that two of the three nestlings had fledged and that the remaining offspring had material hanging from its feet that appeared to hinder flight.…”