Anarhynchus nivosus

Species in this genus were formerly placed in Charadrius, but Charadrius as previously constituted was paraphyletic with respect to Vanellus (Baker et al. 2007, Barth et al. 2013, Dos Remedios et al. 2015, Cerný and Natale 2022) (AOS 2024).

Genetic analyses support the recognition of three subspecies (nivosus, tenuirostris, occidentalis), but resulted in changes to the geographic distributions. Specifically, breeding populations in Florida and along the Gulf of Mexico coast were reassigned from subspecies tenuirostris to subspecies nivosus (Funk et al. 2007, D'Urban Jackson 2020).

This species formerly was treated as conspecific with C. alexandrinus [Kentish Plover] of Eurasia (AOU 1983, 1998), but it is now separated on the basis of differences in male advertisement calls, morphology, and mitochondrial and nuclear DNA, which indicate that the African C. marginatus [Whitefronted Plover] is more closely related to C. alexandrinus or C. nivosus than these two species are to each other (Küpper et al. 2009). Some sources consider Charadrius nivosus, C. alexandrinus, C. marginatus, and the Australian C. ruficapillus [Red-capped Plover] to constitute a superspecies (Vaurie 1965, Mayr and Short 1970, Sibley and Monroe 1990), whereas others include C. javanicus [Javan Plover] in this superspecies (Rittinghaus 1961, Wiersma 1996) (AOU 2011 and sources cited therein).

Large but discontinuous range extending from North America to South America; populations are scattered and declining in many areas, due to habitat loss/degradation, disturbance by humans, and/or impacts of non-native and native predators; much of overall population is concentrated in relatively few areas; many populations are vulnerable to declines resulting from factors associated with climate change.

Breeding range includes the following regions: North American Pacific coast from Washington south to Oaxaca (Mexico) (most numerous from San Francisco Bay south); Pacific coast of South America from Ecuador to Chile; inland areas of North America locally from Saskatchewan (irregular) and Montana (irregular) south to central Mexico; Gulf Coast from Florida to southern Mexico; and locally on islands of the Bahamas and Caribbean region (Page et al. 2009). Approximately 42 percent of all breeding Snowy Plovers in North America occur in only tow areas (Great Salt Lake, Utah, and Salt Plains National Wildlife Refuge, Oklahoma) (Thomas et al. 2012).

Nonbreeding range encompasses islands and coastal areas (and some inland sites) locally from southern Washington south to Chile, Gulf of Mexico coast of the United States and Mexico, Bahamas, Caribbean islands, and islands along northern South America (Page et al. 2009).

This species is represented by a large number of relatively small local populations.

Historical nesting range of the federally listed Pacific coast population included 87 sites (5 in Washington, 29 in Oregon, and 53 in California); currently nesting occurs apparently in only 28 sites (2 in Washington, 6 in Oregon, and 20 in California).

Revised designated critical habitat of the Pacific Coast distinct population segment encompasses 4 units in Washington, 9 units in Oregon, and 47 units in California; all but 9 of these 60 units are regarded as currently occupied by snowy plovers (USFWS 2012).

Poor reproductive success and probable negative effects on roosting and foraging plovers due to human disturbance (including recreational beach use and mechanical raking of beaches) are major problems in coastal areas of North and South America (USFWS 2007, Küpper et al. 2011).

Much habitat has been lost to beach-front development.

The spread of introduced beach grass limits the amount of suitable nesting habitat in some areas along the Pacific coast of North America. At the Great Salt Lake, Utah, expanding stands of the exotic common reed (Phragmites australis) eliminated extensive open areas previously used by nesting by snowy plovers (J. Cavitt, in litt., cited by Page et al. 2009). On the Great Plains, habitat has been lost to impoundments and invasion of non-native tamarisk (Hill 1993).

This species is increasingly vulnerable to predation and clutch loss from native and introduced mammals and birds (Page et al. 1995, 2009).

In Marin County, California, an unusually high proportion of clutches that failed to hatch contained high levels of mercury (Schwartzbach et al. 2005).

This species is vulnerable to oiling of the plumage as a result of oil spills (Mangan et al. 2001).

Snowy plovers sometimes have been injured or killed as a result of collisions or entanglement with fencing or netting used for predator exclosures (see Page et al. 2009).

Some populations are vulnerable to habitat loss/degradation and nest loss as a result of rising sea level and increased storm frequency/intensity or flooding associated with climate change.

The aggregation of breeding plovers at relatively few inland sites and along coastal beaches heavily used by humans make them continually vulnerable to population declines (Thomas et al. 2012).