Consequences of using conspecific attraction in avian conservation: A case study of endangered colonial waterbirds

Published source details Ward M.P., Semel B., Jablonski C., Deutsch C., Giammaria V., Miller S.B. & McGuire B.M. (2011) Consequences of using conspecific attraction in avian conservation: A case study of endangered colonial waterbirds. Waterbirds (formerly Colonial Waterbirds), 34, 476-480.
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Summary

Provide artificial nesting sites for ground and tree-nesting seabirds

A replicated study in 2002–2010 in wetlands in Illinois and Missouri, USA (Ward et al. 2011) reported that artificial islands and rafts were used by Forster’s terns Sterna forsteri and least terns Sternula antillarum, but typically only after decoys and vocalizations were installed. In years without decoys/vocalizations, artificial nesting structures were used in only 2 of 9 cases (two terns present each year). No nesting occurred. In subsequent years with decoys/vocalizations, artificial nesting structures were used in 9 of 9 cases (2–67 terns/site/year). Terns created nests in 8 of 9 cases (4–131 nests/site/year) and produced fledglings in 4 of 9 cases (12–149 fledglings/site/year). The study monitored an artificial island (geotextile and dredge spoil), an artificial floating sandbar and 12 floating nesting platforms, across four sites beyond the known recent breeding range of both tern species. These were monitored every 4–7 days during the tern breeding season, in 1–4 years without decoys/vocalizations then 1–4 years with them.

Use vocalisations to attract birds to safe areas

A replicated, before-and-after study in 2002–2010 in wetlands in Illinois and Missouri, USA (Ward et al. 2011) found that all sites with playback of conspecific calls and decoys were used by adult terns (Forster’s terns Sterna forsteri or least terns Sternula antillarum) and that most supported successful breeding in the first year, but not subsequent years. In the year before using vocalizations/decoys, terns (two) were seen at only one of five sites. There were no nests. In the first year of using vocalizations/decoys, terns were seen at all five sites (7–67 birds/site). Nests were made at four of five sites (4–57 nests/site). Fledglings were produced in three of four sites (14–159 fledglings/site). In subsequent years with vocalizations/decoys, birds were observed in six of seven cases and nested in five of seven cases, but breeding success was much lower: fledglings (12) were produced in only one of seven cases. The study observed strong predation in these subsequent years. The study used five artificial islands or rafts: four with Forster’s tern decoys and intermittent vocalizations; one with least tern decoys and continuous vocalizations. Vocalizations/decoys were used from mid-April each year. Sites were monitored every 4–7 days during the tern breeding season, in one year without decoys/vocalizations then 1–4 years with them.

Use decoys to attract birds to safe areas

A replicated, before-and-after study in 2002–2010 in wetlands in Illinois and Missouri, USA (Ward et al. 2011) found that all sites with decoys and playback of conspecific calls were used by adult terns (Forster’s terns Sterna forsteri or least terns Sternula antillarum) and that most supported successful breeding in the first year, but not subsequent years. In the year before using decoys/vocalizations, terns (two) were seen at only one of five sites. There were no nests. In the first year of using decoys/vocalizations, terns were seen at all five sites (7–67 birds/site). Nests were made at four of five sites (4–57 nests/site). Fledglings were produced in three of four sites (14–159 fledglings/site). In subsequent years with decoys/vocalizations, birds were observed in six of seven cases and nested in five of seven cases, but breeding success was much lower: fledglings (12) were produced in only one of seven cases. The study observed strong predation in these subsequent years. The study used five artificial islands or rafts: four with Forster’s tern decoys and intermittent vocalizations; one with least tern decoys and continuous vocalizations. Decoys/vocalizations were used from mid-April each year. Sites were monitored every 4–7 days during the tern breeding season, in one year without decoys/vocalizations then 1–4 years with them.