Midwest Fish & Wildlife Conference 2018

AUTHORS. Laura Kearns, Anna Crouser, Emily Scott - Ohio Division of Wildlife

ABSTRACT. The Great Lakes population of common terns (Sterna hirundo) has been declining for several decades.  Many wildlife agencies have turned to using artificial nesting platforms (ANPs) to supplement the population.  The Ohio Department of Natural Resources – Division of Wildlife (ODNR) has been using ANPs to support nesting at two locations in Ohio since the early 1990s, but have faced many challenges, particularly predation.  Shifting the locations of the colonies has thus far been the most effective way to deal with excessive predation.  In 2007, the ODNR successfully shifted one of its colonies to a location approximately 15 miles away to deal with excessive fox snake predation.  In 2015-2016, the ODNR and USFWS shifted the location of the second Ohio colony to a location approximately 10 miles away, due to great horned owl predation.   Minimal efforts were made to encourage the terns to shift locations; only wooden common tern models were included on the ANPs to attract terns.   After use by only 4 pairs early in 2015, the colony increased to 84 pairs by the end of the summer.  Unfortunately, due to the late start of the colony and a bad storm at the end of June, only 18 chicks fledged.  In 2016 and 2017, breeding pairs have been slightly lower, at 69 and 79 pairs, respectively, but number of chicks fledged has increased considerably, to 82 and 69 chicks, respectively.  Unfortunately, great horned owls discovered the colony again in 2017, leading to lower chick numbers than in 2016.  While there is some risk to relocating tern colonies with ANPs, and this technique is limited by the availability of suitable locations, these data indicate that relocation can be done successfully with established colonies that use ANPs.