2016 Northeastern Naturalist Notes Vol. 23, No. 3 N22 J.D. Monk, A. DeRose-Wilson, J.D. Fraser, D.H. Catlin, and S.M. Karpanty Observations of Fish Consumption by Piping Plovers Julia D. Monk1,*, Audrey DeRose-Wilson1, James D. Fraser1, Daniel H. Catlin1, and Sarah M. Karpanty1 Abstract - Between April 2014 and August 2015, we observed 4 Charadrius melodus (Piping Plover) consume small, dead fish, including Anchoa mitchilli (Bay Anchovy) on New York barrier islands. These observations are among the first documented evidence of vertebrate prey in Piping Plover diets. While fish consumption is an opportunistic and infrequent occurrence, this behavior may supplement important nutrients in the diet of Piping Plovers in areas without access to high-quality food resources. Further diet analyses are necessary to understand the importance and relative contribution of fish as a prey resource for endangered Piping Plovers. Charadrius melodus (Ord) (Piping Plover) is a shorebird that was listed for protection under the US Endangered Species Act in 1986 (USFWS 1996). Many studies have sought to identify factors that promote Piping Plover reproductive success and population growth in order to inform conservation (Catlin et al. 2015, Cohen et al. 2009, Gaines and Ryan 1988, Goldin and Regosin 1998, Loegering and Fraser 1995). Food abundance and foraginghabitat quality have been identified as significant drivers of Piping Plover reproductive output (Cohen et al. 2009, Loegering and Fraser 1995). As a result, evaluations of habitat suitability frequently incorporate assessments of potential foraging sites and comparisons of prey availability as determinants of high-quality habitat (Catlin et al. 2012, Elias et al. 2000, Nordstrom and Ryan 1996). Studies of foraging-habitat quality generally use arthropod abundance as an index of food availability because the Piping Plover diet is thought to consist mainly of arthropods and marine invertebrates (Elliott-Smith and Haig 2004). However, because the Piping Plover’s threatened status restricts the collection of specimens and disturbance of live individuals, few studies have directly measured the contents of the species’ diet (Elliott-Smith and Haig 2004, Majka and Shaffer 2008). Cuthbert et al. (1999) dissected the gizzards of 4 dead Piping Plover chicks in northern Michigan and found that prey consisted entirely of insects including Hymenoptera, Coleoptera, and Diptera. Shaffer and Laporte (1994), and later Majka and Shaffer (2008), analyzed the contents of several fecal samples collected from the Canadian Atlantic Coast and found only invertebrates, mainly Coleoptera, Diptera, and Amphipoda species. To our knowledge, no published studies have documented vertebrate prey in the Piping Plover diet, although recently an otolith (a calcium carbonate structure found in the inner ear of fish) and a fish eye were detected in piping plover fecal samples (M. Levisen, South Carolina Department of Natural Resources, Charleston, SC, pers. comm.). Herein, we report novel observations of fish consumption by 4 individually marked Piping Plovers on New York barrier islands. Observations. From April 2014 to August 2015, we observed Piping Plover behavior for ~300 h at Cupsogue Beach County Park, Smith Point County Park, the Otis Pike High Dunes Wilderness, Robert Moses State Park, and Jones Beach State Park in New York; these observations were part of a larger study researching the effects of stormand human-created habitat change on Piping Plover demographics and behavior. We 1Department of Fish and Wildlife Conservation, 124 Cheatham Hall, Virginia Tech, Blacksburg, VA 24061. *Corresponding author email - juliadm2@vt.edu. Manuscript Editor: Peter Paton Notes of the Northeastern Naturalist, Issue 23/3, 2016 N23 2016 Northeastern Naturalist Notes Vol. 23, No. 3 J.D. Monk, A. DeRose-Wilson, J.D. Fraser, D.H. Catlin, and S.M. Karpanty documented 4 individual Piping Plovers consuming dead fish on 3 separate occasions. On 17 July 2014, we observed 2 individually marked 29-day-old Piping Plover fledglings each consuming dead Anchoa mitchilli (Valenciennes in Cuvier and Valenciennes) (Bay Anchovy) at a bayside ephemeral pool at Cupsogue Beach County Park, Westhampton Beach, NY. This foraging site was within 100 m of a Sternula antillarum (Lesson) (Least Tern) colony estimated at 162 pairs, and we suspect that terns had dropped several small fish on land, inside the area of moist bay-habitat just above the regular high-tide line inside the fencing demarcating the Piping Plover colony (K. Jennings, New York Department of Environmental Conservation, Stony Brook, NY, pers. comm.). As the Piping Plover fledglings foraged in this habitat, they pecked at the discarded dead fish and eventually swallowed them whole. During a 30-min observation, 1 fledgling consumed 10 fish, and the other fledgling consumed 1 fish. All fish were relatively small; we estimate that they ranged in size from 30 mm to 60 mm, based on a visual comparison to the Piping Plover’s bill length. However, it appeared that the fledglings consumed the fish with difficulty, pecking at the fish multiple times until they had maneuvered them into the proper orientation to swallow them whole. This foraging area was within the fledglings’ normal territory where we had observed them for 30 min each day since hatching, although as younger chicks, they had foraged closer to the ocean and about 50–100 m further from the active Least Tern colony. On 8 July 2015, we observed an individually marked adult male Piping Plover ingest a small fish (species unknown, likely also Bay Anchovy) that had washed up in the wrack in the Otis Pike Fire Island High Dunes Wilderness on the Fire Island National Seashore, Patchogue, NY. The male was foraging with his mate and 2 chicks along the ocean beach, and appeared to encounter and consume the dead fish opportunistically by swallowing it whole. This event occurred within the group’s normal foraging territory, where we had observed the adults and their brood for 30 min each day since the chicks hatched, and no Least Tern nests were nearby. On 14 July 2015, we observed an unmarked adult male Piping Plover similarly swallow whole a dead fish of unknown species along the ocean intertidal zone at Jones Beach State Park, Wantagh, NY; we did not regularly survey this site, and thus were unable to observe whether Piping Plovers at this site regularly consumed fish. Discussion. Our report is the first published record of vertebrate prey contributing to the diet of Piping Plovers. During our extensive behavioral observations, on the rare occasions that we saw these birds consuming fish, the fish were already dead and out of the water. In addition, the dearth of published reports of piscivory by Piping Plovers suggests that fish consumption is opportunistic and that vertebrates are not a significant component of the Piping Plover diet; however, scientific understanding of Piping Plover dietary selection may be incomplete. Previous fecal analyses characterized prey items by identifying relatively intact physical remains found in fecal matter (Majka and Shaffer 2008, Shaffer and Laporte 1994). This method does not allow for the identification of dietary components that degrade prior to defecation. Recently, novel methods of molecular scatology have allowed scientists to analyze fecal DNA and identify prey species (Deagle et al. 2007, Pompanon et al. 2011). DNA sequencing of Calidris pusilla (L.) (Semipalmated Sandpiper) feces revealed that the well-studied shorebird had a broader diet and consumed prey items from more-varied ecosystems than previous reports had suggested (Gerwing et al. 2016). Similar analyses of Piping Plover fecal DNA would provide information for a more precise understanding of the range of prey species that contribute to the Piping Plover diet. 2016 Northeastern Naturalist Notes Vol. 23, No. 3 N24 J.D. Monk, A. DeRose-Wilson, J.D. Fraser, D.H. Catlin, and S.M. Karpanty New York barrier islands are popular recreation destinations that experience heavy human use. The Piping Plover fledglings we observed consuming dead fish occupied an area with high levels of human disturbance, which may have limited their access to high-quality foraging habitat and the amount of time spent foraging (A. DeRose-Wilson, Virginia Tech, Blacksburg, VA, unpubl. data). Under those conditions, and in areas such as those near tern colonies where dead fish are deposited on shore, opportunistic fish-consumption may be an energetically efficient method of supplementing a depressed diet with nutrient-rich, easily caught prey. Future research is necessary to determine whether piscivory in Piping Plovers is influenced by lack of access to other prey or proximity to tern colonies; however, our observations indicate that the diet of Piping Plovers may be more flexible than previously suggested by the scientific literature. Acknowledgments. We thank E.L.B. Raphael and H.A. 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