ANARTIA

Publicación del Museo de Biología de la Universidad del Zulia ISSN 1315-642X (impresa) / ISSN 2665-0347 (digital)

Anartia, 30 (junio 2020): 67-71

Killdeer nesting in northern South America

Extending the breeding range: Killdeer nesting in coastal northern South America

Ampliando el rango reproductivo: anidación del playero gritón en la costa norte de Suramérica

Francisco J. Contreras1, Vanessa G. Salas2, Juan C. Fernández-Ordóñez3

& Adrián Naveda-Rodríguez4

1Programa de Ciencias Ambientales, Universidad Nacional Experimental Francisco de Miranda (UNEFM), Santa Ana de Coro, estado Falcón, Venezuela.

2Centro de Investigaciones en Ecología y Zonas Áridas, Universidad Nacional Experimental Francisco de Miranda (UNEFM), Santa Ana de Coro, estado Falcón, Venezuela.

3Fundación Científica ARA MACAO. Apartado 94, 2201 San Carlos, estado Cojedes, Venezuela.

4Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Mississippi State, MS 39762, USA.

Correspondence: F. Contreras: geogfranciscocontreras@gmail.com

(Received: 17-06-2020 / Accepted: 09-07-2020 / On line: 31-07-2020)

ABSTRACT

We provide the first evidence of Killdeer (Charadrius vociferus) as a resident species in coastal Northern South America. Our observations correspond to 17 sightings and one breeding record of Killdeer in the non-breeding range of northwest- ern Venezuela during the breeding seasons of 2019 and 2020.

Keywords: Charadrius vociferus, Falcon state, non-breeding range, Venezuela, wintering ground.

RESUMEN

Se muestra la primera evidencia del playero gritón (Charadrius vociferus) como una especie residente en la costa norte de Suramérica. Nuestras observaciones se basan en 17 avistamientos y un registro reproductivo en el noreste de Venezuela durante la temporada de anidación 2019 y 2020, el cual se encuentra fuera del área de anidación conocida previamente para la especie.

Palabras clave: áreas de invernada, Charadrius vociferus, distribución no-reproductiva, estado Falcón, Venezuela.

The Killdeer (Charadrius vociferus Linnaeus, 1758), a least concern plover of the family Charadriidae, has a disjunct distribution in the Americas with three recog- nized subspecies ( Jackson & Jackson 2020). C. vociferus vociferus is a partial migrant distributed in North America (breeding range) and northern South America and the Caribbean (non-breeding range), whereas C. vociferus peruvianus and C. vociferus ternominatus are residents in western South America (Ecuador, Peru and northwestern Chile), and the Greater Antilles, respectively (Restall et al.

2006, Conklin 2019, Schulenberg et al. 2019). Although the distribution of Killdeer subspecies is apparently well defined, molecular analyses suggest that this species was more abundant and widely distributed before the glacial period than today (Küpper & dos Remedios 2019).

The nominal subspecies is considered rare and vagrant in northern South America, particularly in Trinidad & Tobago, and Venezuela (Hilty 2003, Restall et al. 2006, Kenefick et al. 2019). Between 1945 and 2018 there have been 12 occurrence records in nine localities of four coastal

F. J. Contreras, V. G. Salas, J. C. Fernández-Ordóñez & A. Naveda-Rodríguez

and one Andean states of Venezuela, all but one occurring during the boreal winter months (Fig. 1, Table 1; Fried- man & Smith 1950, Hilty 2003, eBird 2020). This species is considered a partial migrant (Conklin 2019); therefore, it is not unusual recording it during the breeding season (March to September, Jackson & Jackson 2020) in north- ern South America non-breeding grounds as observed in Colombia and Morrocoy National Park in Venezuela (eBird 2020). Here, we report 17 sightings and one breed- ing record of Killdeer in northwestern Venezuela during the breeding seasons of 2019 and 2020.

Between April 2019 and June 2020, we conducted monthly ornithological surveys in a 1-km transect located in Sabana Larga, Colina County, Falcón State, Venezuela (11°26’ N, 69°35’ W, 10 m asl). Land cover in our tran- sect corresponds to a matrix of urban and highly disturbed xeric vegetation with temporary ponds of wastewater. On April 4, 2019 we photographed one adult Killdeer (Fig. 2A) that was foraging and performing short distance flights; subsequently, between May 2019 and March 2020 we recorded up to three adults simultaneously with the same behavior. In April and May 2020 two adults were observed performing distraction displays. On June 6 and 12, 2020 we observed five individuals (two adults, three juveniles, Fig. 2B-C), and we found an unhatched egg that was still protected by the distraction displays of the adults (Fig. 2D). The egg was laid on bare sandy soil, close

(ca. 20 cm) to a shoreline purslane (Sesuvium portulacas- trum L.). Birds, egg and distraction displays were consis- tent with previous descriptions for this species (Gochfeld 1984, Restall et al. 2006, Marchant et al. 2010, Chávez- Villavicencio et al. 2015).

Our monthly records, gathered for more than one year, constitute the first evidence of Killdeer as a resident spe- cies in Venezuela, and the second nesting record known for the species in northern South America. The Killdeer nest in Venezuela was located ca. 132 km SSE from a breed- ing pair in Bubali, Noord, Aruba (Prins et al. 2009), and ca. 860 km NE from a successful nest located at 2500 m. above sea level in Cundinamarca, Colombia (Castro-Var- gas et al. 2019). Whether these nesting records belong to any of the three recognized subspecies remains unknown. In either case, these findings suggest that this species could be extending its breeding range (Küpper & dos Remedios 2019).

The reasons for extending the breeding range or return- ing to a former range cannot be answered on the basis of three records. However, we speculate that climate change, resource availability, and/or competition could be influ- encing the decision of some individuals to remain on their previous non-breeding grounds throughout the year. Kill- deer population density seems to be regulated by space competition and resource stability during the breeding season ( Jackson & Jackson 2020). Finding areas with no

Figure 1. Occurrence records of Killdeer (Charadrius vociferus) in Venezuela. Black circles correspond to 12 records during the boreal winters of 1949-2019. Black triangle corresponds to 17 monthly records during the breeding and nonbreeding seasons of 2019 and 2020 and which are described here.

Killdeer nesting in northern South America

Table 1. Historical and contemporary occurrence records of Killdeer (Charadrius vociferus) in Venezuela.

F. J. Contreras, V. G. Salas, J. C. Fernández-Ordóñez & A. Naveda-Rodríguez

Figure 2. Photographic evidence of adult, juveniles and eggs of Killdeer during the breeding season of 2019 and 2020 in northwestern Venezuela. Picture A: adult recorded on April 4, 2019. Pictures B to D: juveniles and egg recorded on June 9, 2020.

intraspecific competition and year-round stable weather and food resources, such as northern South America, could explain why some individuals from a migrant popu- lation are not returning to their former breeding grounds.

Killdeers and their distraction displays during breeding are conspicuous; thus, it is unlikely that this species had gone undetected as a breeder in Venezuela. As suggested by Nol (2019), “Plover researchers are encouraged to al- ways report the stage of the annual cycle of their study period, especially in studies reporting distributions of par- tial migrants or sedentary species.” We extend this recom- mendation to birdwatchers whose observations of species natural history reported in their lists are highly valuable to our understanding of bird biology.

ACKNOWLEDGEMENTS

We thank Rómulo García for his assistance during field surveys. We are also grateful to two anonymous

referees for helpful assistance revising an early version of this report.

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