Piping Plover - U.S. Fish and Wildlife Service

WM 2.2.2.3 Factor C. Disease or predation:
Disease
Neither the final listing rule nor the recovery plans state that disease is an issue for the
species, and no plan assigns recovery actions to this threat factor. Although researchers
increased vigilance following detection of several cases of West Nile virus in breeding
Northern Great Plains piping plovers and Type E botulism in the Great Lakes breeding
population, the USFWS is not aware of instances of disease in nonbreeding piping
plovers. Of the 181 piping plovers submitted to the USGS National Wildlife Health
Center in Madison, Wisconsin, since 1986, 164 died from unknown causes, trauma, or
emaciation. In the southeastern U.S., the cause of death of one piping plover received
from Texas was emaciation (C. Acker, USGS, pers. comm. 2009). These data, obtained
from the National Wildlife Health Center do not include data from necropsies performed
on piping plovers by other laboratories.
Avian influenza testing is conducted on a large variety of shorebirds from most of the 50
states and associated islands. Only two documented samples were collected from live
piping plovers and sent to the Kissimmee Diagnostic Laboratory in Florida for avian
influenza testing in 2006. Both birds tested negative (M. Hines, USGS, pers. comm.
2009). The Department of the Interior has tested 14,261 shorebirds in the families of
Charadriidae and Scolopacidae since 2006. Bird species testing positive for low
pathogenic avian influenza consist of Pacific golden-plover (1), bar-tailed godwit (3),
dunlin (8), marsh sandpiper (1), red knot (1), sanderling (1), sharp-tailed sandpiper (1),
and western sandpiper (1) (Acker, pers. comm. 2009). Other laboratories have ongoing
shorebird testing, but results were not available for this review.
Based on information available to date, we conclude that West Nile virus and avian
influenza remain a minor threat to shorebirds, including the piping plover, on their
wintering and migration grounds.
Predation
The 2003 Great Lakes recovery plan expressed concern about the increase in predators
(fox, coyotes, dogs, and cats) that are present year-round on the wintering grounds.
Although not the subject of a specific recovery plan action, investigations into effects of
predation on nonbreeding piping plovers falls under Great Lakes recovery plan priority 1
action 2.16, i.e., identification and reduction of additional threats to winter populations.
The impact of predation on migrating or wintering piping plovers remains largely
undocumented. Except for one incident involving a cat in Texas (NY Times 2007), no
depredation of piping plovers during winter or migration has been noted, although it
would be difficult to document. Avian and mammalian predators are common
throughout the species’ wintering range. Predatory birds are relatively common during
fall and spring migration, and it is possible that raptors occasionally take piping plovers
(Drake et al. 2001). It has been noted, however, that the behavioral response of
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