Colonization of Hispaniola by Margarops fuscatus Vieillot (Pearly-eyed Thrasher)
Wayne J. Arendt1,*, María M. Paulino2, Luis R. Paulino2, Marvin A. Tórrez3, and Oksana P. Lane4
1International Institute of Tropical Forestry, USDA Forest Service, Sabana Field Research Station, HC 02 Box 6205, Luquillo, PR 00773, USA. 2Grupo Acción Ecológico, Calle Gabriel Garcia, No.105, Zona Colonial, Santo Domingo, Dominican Republic. 3Universidad Centroamericana (UCA), Instituto Interdisciplinario de Ciencias Naturales, Managua, Nicaragua. 4Biodiversity Research Institute, 276 Canco Road, Portland, ME 04103, USA. *Corresponding author.
Urban Naturalist, No. 23 (2019)
Abstract
Margarops fuscatus (Pearly-eyed Thrasher) is the Caribbean’s premier avian supertramp. Concurrent with urban development, it continues to expand its geographical and habitat range throughout the region, especially in the Greater Antilles. Through personal research, supplemented by relevant publications, unpublished results from others’ research and casual observations, as well as checklists including Pearly-eyed Thrasher sightings submitted to Cornell University’s eBird online database, we document the species’ apparent colonization of Hispaniola. Most sightings of pioneering Pearly-eyed Thrashers in Hispaniola have been made by “eBirders” from coastal urban sites, particularly from resorts, hotels, and golf courses. Historical and contemporary evidence and the recent colonization of several islands in the northern Caribbean and The Bahamas, strongly suggest that the Pearly-eyed Thrasher may very well attempt to gain a foothold on the North American continent in the near future as a result of the effects of global climate change pursuant to natural and anthropogenic disasters and accelerated urban development in the USA and the Greater Caribbean Basin. Natural and human-influenced habitat alteration often culminates in a reduction in avian species richness, thus opening an avenue for colonization by this intrepid avian supertramp.
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2019 Urban Naturalist No. 23 2019 URBAN NATURALIST No. 23:1–24 W.J. Arendt, M.M. Paulino, L.R. Paulino, M.A. Tórrez, and O.P. Lane
Colonization of Hispaniola by Margarops fuscatus Vieillot (Pearly-eyed Thrasher)
Wayne J. Arendt1,*, María M. Paulino2, Luis R. Paulino2, Marvin A. Tórrez3, and Oksana P. Lane4
Abstract - Margarops fuscatus (Pearly-eyed Thrasher) is the Caribbean’s premier avian supertramp. Concurrent with urban development, it continues to expand its geographical and habitat range throughout the region, especially in the Greater Antilles. Through per- sonal research, supplemented by relevant publications, unpublished results from others’ research and casual observations, as well as checklists including Pearly-eyed Thrasher sightings submitted to Cornell University’s eBird online database, we document the species’ apparent colonization of Hispaniola. Most sightings of pioneering Pearly-eyed Thrashers in Hispaniola have been made by “eBirders” from coastal urban sites, particularly from resorts, hotels, and golf courses. Historical and contemporary evidence and the recent colo- nization of several islands in the northern Caribbean and The Bahamas, strongly suggest that the Pearly-eyed Thrasher may very well attempt to gain a foothold on the North Ameri- can continent in the near future as a result of the effects of global climate change pursuant to natural and anthropogenic disasters and accelerated urban development in the USA and the Greater Caribbean Basin. Natural and human-influenced habitat alteration often culminates in a reduction in avian species richness, thus opening an avenue for colonization by this intrepid avian supertramp.
Introduction
There are 2 distinct and mutually exclusive life-history strategies in insular landbirds: (1) competitors and (2) colonizers. Island birds are either (1) highly com- petitive, k-selected (“high-S” or highly sedentary) species (MacArthur and Wilson 1967, Parry 1981) comprised of sustained populations of long-lived individuals living in stable environments that successfully compete for resources and produce few young, e.g., woodpeckers, parrots, and trogons; or (2) non-competitive, preem- inent colonizers comprised of often short-lived individuals that produce numerous offspring throughout their lives, undergo exponential population growth, and popu- late ephemeral or disturbed environments, e.g., flycatchers, pigeons, and Coereba flaveola (L.) (Bananaquit). Most colonizers are generalists, especially in terms of food and habitat (Diamond 1974, 1975; Diamond and Marshall 1977a, 1977b; Horn and Rubenstein 1986; see also several additional and pertinent citations in Arendt
1International Institute of Tropical Forestry, USDA Forest Service, Sabana Field Research Station, HC 02 Box 6205, Luquillo, PR 00773, USA. 2Grupo Acción Ecológico, Calle Gabriel Garcia, No.105, Zona Colonial, Santo Domingo, Dominican Republic. 3Universi- dad Centroamericana (UCA), Instituto Interdisciplinario de Ciencias Naturales, Managua, Nicaragua. 4Biodiversity Research Institute, 276 Canco Road, Portland, ME 04103, USA. *Corresponding author - waynearendt@gmail.com.
Manuscript Editor: Sabina Caula
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2006). Colonizers are collectively known as “tramps”, namely, A-tramps, B-tramps, C-tramps, D-tramps, and supertramps (Diamond 1974). A-tramps are most closely affiliated ecologically with high-S species, whereas supertramps are the antitheti- cal, prototypical colonizers. Margarops fuscatus Vieillot (Pearly-eyed Thrasher, hereafter also PETH or Pearly-eye) is the Caribbean’s premier supertramp (see Arendt 2006 and citations therein for more details).
By definition, although confined to species-poor islands and habitats, a super- tramp possesses the innate ability to disperse over a wide geographic area. Not surprisingly, the PETH inhabits at least 80 islands and cays throughout the Greater Caribbean Basin, from Rum Cay and San Salvador in the Southern Bahamas south to Bonaire in the Netherlands Antilles and islands off the northern coast of South America (IUCN Red List 2018). Overall, the Pearly-eyed Thrasher has a north– south geographical range of more than 3000 km (Arendt 2006). Yet, with the excep- tion of Puerto Rico, Pearly-eyes are noticeably absent from the larger, species-rich islands of the Greater Antilles such as Cuba, Jamaica, and (formerly) mainland Hispaniola, historically inhabiting only the smaller islands of the Lesser Antilles and the diminutive species-poor satellite islands in the Greater Antilles.
However, notwithstanding the previously documented range of the PETH, nu- merous fairly recent sightings on Hispaniola, mostly in coastal, urban areas (see Pearly-eyed Thrasher range map at: http://www.eBird.org/), testify to the fact that the PETH continues to expand its geographical and habitat range in the Greater An- tilles. Like other mimids, e.g., Mimus polyglottos (L.) (Northern Mockingbird), that share a strong mutualistic bond with humans and their highly developed environs (David et al. 1990, Farnsworth et al. 2011, Stiles 1982), the Pearly-eyed Thrasher also flourishes in species-poor anthropogenic settings wherein interspecific and dif- fuse competition are significantly reduced and diverse food sources (often human introduced) abound (Arendt 2006). Urban centers and suburbia are favored by pio- neering thrashers. Pearly-eyes are notorious for taking advantage of a wide variety of seeds, fruits, and their attendant insects found in cultured orchards, gardens, and ornamental plants dominating the landscape in urban settings, especially in and around golf courses, hotels and resort grounds (Arendt 2006, del Hoyo et al. 2005). Herein, our main objective is to document the Pearly-eyed Thrasher’s presence and apparent colonization of mainland Hispaniola and to chronicle the continued expan- sion of the Pearly-eyed Thrasher’s geographical and habitat range in the northern Caribbean, particularly the Turks and Caicos islands and the northern Bahamian islands, e.g., Great Exuma and New Providence.
Methods
Previous and contemporary avian research and casual observation on mainland Hispaniola
The authors, excluding O.P. Lane, have been surveying and banding birds throughout the Dominican Republic since 1976. As a Peace Corps volunteer as- signed to the Santo Domingo Natural History Museum (1976–1978), W.J. Arendt and his Dominican counterpart, Tomás A. Vargas Mora, conducted audio-visual
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surveys in a variety of habitats, from mangroves and thorn scrub to broadleaf and pine forests, throughout the Dominican Republic, multiple off-shore cays, and 2 nearby islands, Saona and Beata (see figure 1 in Arendt et al. [1979] for selected sites and geographical descriptions). In addition, they conducted mist-netting and banding operations in the city of Santo Domingo (1978, sector Gascue; #452 Avenida Bolivar: 18.46479°N, 69.92116°W) and surrounding pig farms, e.g., En- gombe—see Arendt and Vargas (1984) for sites and geographical coverage. Other netting and banding sites and habitats included dry forest (southeastern peninsula, Saona Island, Monte Cristi), pine forest (Valle Nuevo National Park, Constanza), and mangrove forest near Sánchez, Samaná Bay, from 1981 to 1988 (see Arendt 1992 for a general description of habitat types). Since 1995, working as biological consultants for several local and international organizations, M.M. Paulino and lat- er (in 2011) L.R. Paulino have been conducting surveys and mist-netting operations throughout the Dominican Republic: north—San Francisco de Macorís, Nagua, Puerto Plata, Bonao, Santiago, Jarabacoa; south—Pedernales, Barahona, Baní, Du- vergé, Neiba, Jimaní, San Cristóbal, Azua; east—San Pedro de Macorís, Higüey, Miches, Hato Mayor, Sabana de la Mar, Samaná, Monte Plata; west—Monte Cristi, Santiago Rodríguez, Dajabón, Elías Piña, Valverde Mao; and urban areas—Santo Domingo, San Francisco de Macorís, Jarabacoa, San Pedro de Macorís, San Cris- tóbal, and Monte Plata.
All Pearly-eyed Thrasher sightings included in Appendix 1 constitute data retrieved from the “eBird” online data base except 3 temporally widely scattered records from 1984 (Chandler S. Robbins and Tomás A. Vargas Mora), 2014 (María Milagros Paulino, Kate Wallace, Danilo Mejilla), and 2016 (María Milagros Pau- lino). Checklist dates ranged from the earliest (1995) through July 2018 (Fig. 1; eBird 2012). Descriptions of the specific sites at which Pearly-eyed Thrashers were encountered are recorded textually (herein or cited publications) and visually (eBird Species Map) at Cornell University’s international eBird online database (Sullivan et al. 2009).
The banding site at which a single unknown molt cycle, basic plumaged (UCB) adult male Pearly-eyed Thrasher was (a) mist-netted (19 February 2017), (b) measured and weighed using dial calipers accurate to 0.02 mm and weighed with a 300-g spring scale with 0.05-g increments (Table 1), and (c) photographed (Fig. 2) was located within the Plaza de Cultura (sector Gascue) of Santo Domingo
Table 1. Morphometrics of an unknown molt cycle, basic plumaged (UCB) adult male Pearly-eyed Thrasher captured on 19 February 2017 within the Plaza de Cultura (Gascue sector) Santo Domingo, Dominican Republic. Body mass is measured in grams (g), longitudinal characters in millimeters (mm). The wing chord and body mass corroborate that this bird is a male and it hatched near sea level (Arendt 2006:figure 5.2). It was first observed on 8 October 2016 and singing on subsequent surveys in 2018.
Culmen
Length Width Depth Body mass Wing Chord Primary 9 Tarsus Tail
Measurment 17.35 6.65 8.9 97 136 85 36.35 105
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(18.47204°N, 69.90735°W). The capture of the adult male Pearly-eyed Thrasher was part of our ongoing (2014–present) USAID/DR–USDA Forest Service/IITF Santo Domingo ULTRA green area avian research project. From 2015 to pres- ent, we (W.J. Arendt, M.M. Paulino, L.R. Paulino) have been conducting avian point-counts associated with the US Forest Service iTree program (https://www. itreetools.org/). Some 80 avian count plots are distributed about equally among 4 sectors of Santo Domingo (Zona Colonial, San Carlos, Ciudad Nueva, Gascue).
In addition to our personal research and the inclusion of eBird sightings, to include a more comprehensive history of the Pearly-eye’s presence (or absence) throughout Hispaniola, we gleaned pertinent information from published references (e.g., Keith et al. 2003; Latta et al. 2006; Woods and Ottenwalder 1983, 1986; see also Arendt 2006 for several additional sources) and asked fellow avian researchers and birders for pertinent information regarding their research studies and birding
Figure 1. Map of Pearly-eyed Thrasher encounters (sightings and mist nettings) on mainland Hispaniola. Numbers refer to the geographical coordinates (latitude north and longitude west) of each encounter. See Appendix 1 and Table 2 for details.
Figure 2 (folowing page). Photos taken 19 February 2017 of an unknown molt cycle, basic plumaged (UCB) adult male Pearly-eyed Thrasher captured in a mist net within the Plaza de Cultura, Gascue sector, Santo Domingo, Dominican Republic. (A) In hand: Note the dis- tinct, white malar streak, pronounced “chevrons” of the breast and the definitive white abdomen; (B) In tree: Note the previously mentioned characters, plus the extensive white on the underside of the rectrices (photos by Luis R. Paulino).
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Figure 2. [Caption on preceding page.]
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Table 2. Additional information pertaining to Pearly-eyed Thrasher (PETH) encounters (mist netting and reports by researchers, local residents and eBirders) on mainland Hispaniola: site reference points as shown in Figure 1, coordinates (latitude and longitude), time frame, source, number of persons reporting and thrashers observed. [Table continued on following page.]
Latitude Point (°N)
1 18.332125
2 18.511109
3 18.714509
4 18.662961
5 18.518777
6 18.579833
7 18.458768
8 18.518317
9 18.493305
10 19.785684
11 18.376535
12 19.786464
13 18.377745
14 18.556926
15 18.515947
16 18.528776
17 18.516019
18 18.750533
19 18.528775
20 18.545315
21 18.547161
22 18.374431
23 19.292019
24 18.342883
25 18.335502
26 18.369188
27 18.369460
28 18.555421
29 18.517275
30 18.694708
31 18.694708
32 18.538911
33 18.423892
34 18.422124
35 18.559570
36 19.468028
37 18.701537
Longitude (°W)
68.811647
68.376589 68.450680 68.394719 68.323050 68.329333 68.400879 68.361502
Month Year
Date
3 Feb 1984
23, 25 Jan 1995 28 May 2003 30 May 2003 20 Feb 2003
16 Nov 2007
16 Nov 2007
26 Apr 2008
28 Jun 2009
11 Jan 2011
4 Dec 2011 23–24 Dec 2011 29, 31 Dec 2011 12 Jan 2012
4, 6 Jan 2013 6 Jan 2013
7 Jan 2013 12 Jan 2013 31 Mar 2013
12 May 2013
19, 22–24 May 2013 9, 13 Nov 2013 12–14 Nov 2013
2 Dec 2013
21 Dec 2013
9 Jan 2014
9 Jan 2014
10 Jan 2014
16 Jan 2014
22 Jan 2014
31 May 2014
18 Aug 2014 11 Mar 2015 14 Mar 2015 14 Mar 2015 29 Apr 2015 25 May 2015
Source
No. of per. PETH
11 11 4 69.953930 6
72.243433 68.846489 72.245128 68.847626 68.369808 68.377265 68.367741
68.379593 68.538004 68.367741 68.350794 68.351738 68.843722 69.186915 68.823037 68.812566 68.839774 68.840370 68.369336 68.373606 68.432937 68.432937
68.362727 68.921254 68.889927 68.367770 70.680440 68.437620
1 12 12 12 1 1 1
1 1 3 5 5
11 11 12 12
1 1 1 1 1 5
8 3 3 3 4 5
3
1 5 5
1984
1995
2003
2003
2003
2007
2007
2008
2009
2011
2011
2011
2011
2012
2013
2013
2013
2013
2013
2013
2013
2013
2013
2013
2013
2014
2014
2014
2014
2014
2014
2014
2015
2015
2015
2015
2015
Chandler S. Robbins, 2 1 Tomás A. Vargas Mora
Peter Adhemar 1 1 Andy & Mark Dettling 2 1 Andy & Mark Dettling 2 1 Olivier Langrand 1 4 Caribbean WorldBirds 1 1 Ted Goshulak 1 1 Tamie Bulow 1 1 Frank Bingham 2 1 Jim Zook 1 1 Gerry McChesney 2 2 Douglas Long 1 1 Robert Hirst 1 2 Jeffrey Climie 1 2 Mary Margaret Ferraro 1 1 Tim Healy, 2 1 Mary M. Ferraro
Tim Healy 13 1 Mike V. A. Burrell 1 1 Byron Swift 1 1 Lisa Williams 1 2 Pam Overmyer 1 2 Kevin Hannah 2 1 Jorge Brocca 1 3 Freya Uvarova 3 1 Paul Pratt 4 2 Mary M. Ferraro 16 1 Wesley Hochachka 1 1 Sarah Dzielski 5 2 Sarah Dzielski 5 1 Andrey Vlasenko 1 1 María Paulino, 3 2 Kate Wallace,
Danilo Mejilla
Robert Parsons 1 1 John Sullivan 2 1 John Sullivan 2 1 Stephen Brauning 2 1 Chris Corcino 1 1 Eduardo Costoya 1 1
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trips, e.g., time frame, locations, and any unpublished sightings they may have. Following, are summaries of research studies described by our colleagues:
Chris Rimmer, Kent P. McFarland, James Goetz and their associates at the Vermont Center for Ecostudies (VCE), conducted field studies on His- paniola from 1984 to 2018, many of which involved presence/absence surveys and/or intensive demographic studies of Catharus bicknelli (Ridgway) (Bicknell’s Thrush) throughout the Dominican Republic and in the La Selle and Macaya massifs of Haiti. More extensive protocols involved playback elicitation surveys of potential habitat, focusing on wet and mesic broadleaf forest. During all surveys, all other species were noted. Most surveys were conducted at mid- and high elevations, but some were conducted in low-elevation, wet, broadleaf forests (e.g., Parque Nacional Del Este, Los Haitises), including an urban site (Jardín Botánico Nacional). They also operated arrays of mist nets for short periods (usually 1–3 days) at a small number of sites during the course
Table 2, continued.
Latitude Point (°N)
38 18.545074
39 18.545208
40 19.292693
41 18.472040
42 19.291844
43 18.652263
44 18.517659
45 19.139958
46 18.544834
47 18.544835
48 19.056010
49 18.528776
50 18.293294
51 18.369189
52 18.345854
53 18.714227
54 18.734276
55 19.056010
56 18.804631
57 18.293294
58 18.377801
59 19.293869
60 19.056010
Longitude (°W)
Month Year
Date
12 Dec 2015 25 Dec 2015 27 Mar 2016 8 Oct 2016 19 Jan 2017 21 Jan 2017
13 Apr 2017
14 Jul 2017 15–22 Apr 2017 10 Dec 2017
8 Jan 2018
9 Jan 2018
16 Jan 2018
17 Jan 2018
20 Jan 2018
27 Jan 2018
4 Mar 2018
14 Mar 2018
15 Mar 2018
30 Mar 2018
31 Mar 2018 23–24 Jun 2018
25 July 2018
Source
No. of per. PETH
68.350738 12 68.351764 12 69.188508 3 69.907350 10 69.188515 1 68.365302 1
68.375776 4 71.070344 7 68.352125 4 68.352125 12 69.455190 1
68.367741 1 68.711439 1 68.839774 1 68.819548 1 68.447406 1 68.481047 3 69.455190 3 68.573678 3 68.711439 3 68.842449 3 69.202616 6
69.455190 7
2015
2015
2016
2016
2017
2017
2017
2017
2017
2017
2018
2018
2018
2018
2018
2018
2018
2018
2018
2018
2018
2018
2018
Geoffrey Groom 1 1 Isabel Apkarian 1 2 James Holdsworth 2 3 María Milagros Paulino 2 1 Daniel Gagné 1 1 Doris Guimond, 1 1 Claude Gagnon
Marta Curti 2 1 Jonathan Oliveras 1 1 Scott Stafford 3 2 David Bernstein 1 5 John C Cobb, 3 1 Julio Salgado
Ryan Larson 2 2 Simon Best 3 3 Robert Ruvolo 2 1 Daniel Gagné 1 1 Brian Menker 1 1 Justin Streit 1 1 Adam Winer 3 1 Elizabeth Geissler 1 2 John Hull 3 1 John Hull 1 1 Maximo Marcos Peña, 2 1 Roca Eladio Fernández
Eric Baldo 1 1
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of these extensive surveys (e.g., in Valle Nuevo, Los Haitises, Sierra de Neiba, Reserva Científica Ebano Verde, Loma Quita Espuela [LQE], Guaconejo, La Visite, Macaya). Some of these sites were sampled in just 1 winter (Valle Nuevo [Constanza], Los Haitises, Neiba, Guaconejo), whereas others were sampled during multiple winters (LQE, La Visite, Macaya). Intensive mid-winter mist netting and banding were carried out from 1995 to 2010 at 2 sites in the Sierra de Bahoruco (Pueblo Viejo and Palo de Agua; Lloyd et al. 2016). At both sites, arrays of nets were oper- ated, and all resident birds were captured and banded during the avian breeding seasons of May 2005 and 2006 (Townsend et al., in press).
James Goetz, in addition to conducting extensive surveys for Bicknell’s Thrush throughout the Dominican Republic (excluding the North West) and at all elevations (1997–2002), from 2008 to 2018 he birded many sites on the ~60-km La Selle Ridgeline chiefly above 1200 m in southeast Haiti, in the 3 national parks: La Visite, and Units 1 and 2 of Forêts des Pins.
Joseph M. Wunderle Jr. and Steven C. Latta carried out collaborative stud- ies as part of a US Forest Service/IITF research project at mid- to high elevations in the La Vega Province of the Dominican Republic from 1992 to 1995 in coffee plantations and pine forest at multiple locations (Con- stanza, Ebano Verde, Manabao, and Jarabacoa).
Steven C. Latta, working for the National Aviary in Pennsylvania, has con- ducted personal research across the southern slope of the Sierra de Ba- horuco, Pedernales Province, along a gradient from low-elevation thorn scrub to mid-elevation dry forest and high-elevation pine forest from 1996 to present, and in the La Joya, Duarte Province, at mid-elevation cacao plantations and riparian habitat from 2006 to present.
Sean Christensen, affiliated with the Universite Lumiere, has lived full-time in Cayes, Haiti, from January 2009 to the present. He has birded exten- sively in the following departments: du Sud, Grand-Anse, Nippes, Ouest, Sud-Est, Nord and Nord-Est (Plateau Central, Artibonite), including 2 excursions to Labadie on the northern coast. Habitats that Sean visited include urban (Port-au-Prince, Cap-Haïtien, Cayes, Jérémie, Carrefour), fertile plains (Les Cayes), mangrove forest, coastal, satellite islands (Île-à-Vache, Caye Ramier, Grosse Caye), mountain forest and mountain savanna-type habitat as well as xeric habitat.
Anderson Jean and Maxon Fildor, 2 Haitian-born birders and active members of the “Jeunes en Action pour la Sauvegarde de l'Ecologie”, have been studying and observing birds together in Haiti and the Dominican Republic since 2006. In Haiti, they have visited almost every area important to birds and most major habitats, including wetlands (Lagon aux Boeuf, and Baie de Mancenille in the northeast near Fort-Liberté; Trou Caïman, and Lac Azuéi in the west near Port-au-Prince; the Baie des Flamands, Étang Laborde, Étang Droite, and the Île-à-Vache mangroves in the south near Les Cayes) as well as dry forest in Belle-Anse and Anse-à-Pitres in the
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southeast. At high elevations, they have visited all the remaining karst limestone cloud forest in the Massif de la Hotte (Morne Grand Bois, Morne Deux Mamelles, Morne Grande Colline, Macaya, Ti l'Étang [Department of Grande-Anse]) and in the Massif de La Selle (Morne La visite, Morne La Selle, Forêt des Pins). In the Dominican Republic, they have observed birds in the Ébano Verde Scientific Reserve (Constanza), Los Haitises, Loma El Alto de Canela, and the Sierra de Bahoruco mountains.
Spatial and numeric statistical analysis
We used R (R Core Team 2017) and its “adehabitatHR” package to estimate the Pearly-eyed Thrasher’s distribution throughout Hispaniola (Calenge 2006). We used the package MASS to correlate the number of eBird checklists with the number of new sightings. For the correlation, log-transformed data were entered into a linear generalized model and, after deriving the mathematical residuals, we evaluated the results of the model against the response variable (new checklists). The “adehabitatHR” package was originally designed to quantify home range (Calenge 2015), but in this instance, we used the Kernel UD model (UD = utilization distribution) considering “the use of space from a purely spatial point of view” (Calenge 2015:59), not taking time into account. Our analysis helps to visualize a thermal map of the locations through the probability of density, according to the coordinates (x, y).
Results
Pearly-eyed Thrasher presence–absence on mainland Hispaniola
Historically, information on the presence of the Pearly-eyed Thrasher on the main island of Hispaniola is scant and ambiguous. Avian specimen collectors and museum curators listed the species occurrence on Hispaniola in general terms only (see Arendt 2006:appendix 3 for more details). Contrarily, the contemporary his- tory of the Pearly-eyed Thrasher’s presence or absence on Hispaniola has been documented in more detail, owing to more than 100 combined years of concerted effort on the part of researchers, birders, and casual observers throughout the Do- minican Republic and Haiti. The Pearly-eyed Thrasher remained undetected during 2 years of ornithological surveys conducted in eastern Dominican Republic from 1974 to 1976 (Keith et al. 2003) and during 12 years of surveys (1976–1988) car- ried out by W.J. Arendt and T.A. Vargas Mora in all major habitat types, ranging from urban and coastal dry forest to remote broadleaf, pine, and mangrove forests throughout mainland Hispaniola, multiple off-shore cays and 2 nearby islands (Saona, Beata). Likewise, no Pearly-eyed Thrashers were captured or detected during 23 years (1995–present) of personal and collaborative avian surveys and mist-netting conducted by M.M. and L.R. Paulino in most habitats, including urban, in the Dominican Republic. Moreover, neither did several other avian researchers capture or otherwise detect Pearly-eyed Thrashers during their collective years of research and observations, e.g., 34 years (1984–2018) by the Vermont Center for Ecostudies Group (VCE), which conducted numerous studies in most habitats,
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including urban, throughout the Dominican Republic and parts of Haiti; or during the 26 combined years (1992–2018) of collaborative and personal research carried out by J.M. Wunderle Jr. and S.C. Latta at their numerous study sites located along a coastal to highland elevational gradient encompassing most habitats in the Domini- can Republic (sources: C.C. Rimmer, K. McFarland and J. Goetz, VCE, Vermont, USA, 2018 pers. comm.; J.M. Wunderle Jr., USFS/IITF, San Juan, PR, USA, and S.C. Latta, National Aviary, Pittsburgh, PA, USA, 2018 pers. comm.). In Haiti, no Pearly-eyed Thrashers were detected by Sean Christensen, a volunteer, regional reviewer for eBird, who has searched for birds in that country for almost a decade (2009–present). To date, he has observed 167 species in Haiti and has submitted 405 checklists to the online eBird data repository. (Sean Christensen, Universite Lumi- ere, Cayes, Haiti, 2018 pers. comm.). Likewise, Anderson Jean and Maxon Fildor have not encountered the Pearly-eyed Thrasher during their 12 years (2006–present) of studying and searching for birds in Haiti (A. Jean and M. Fildor, Jeunes en Action pour la Sauvegarde de l'Ecologie en Haïti [JACSEH], 2018 pers. comm.).
In modern times, the Pearly-eyed Thrasher was first documented on Hispan- iola’s “terra firma” in 1984 in dry forest within Parque Nacional Del Este in southeastern Dominican Republic when an individual was captured in a mist net set by C.S. Robbins and T.A. Vargas Mora (Wiley and Ottenwalder 1990). A small “resident” population was discovered in a large (2–3 km) patch of secondary scrub forest near Punta Cana in 1999 (Keith et al. 2003, Latta et al. 2006). Thereafter, commensurate with rapid urban development and the establishment of numerous resorts and vacation spots, particularly along the eastern and southeastern coasts (Fig. 1), Pearly-eyed Thrasher sightings increased substantially by 2013, especially near urban centers (Appendix 1; Figs. 1, 3) and in close vicinity of resorts, hotels,
Figure 3. Total number of Pearly-eyed Thrashers reported (sightings and mist nettings) each year on mainland Hispaniola.
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and adjacent manicured grounds, as well as heavily populated suburbs, especially in the Punta Cana area (Appendix 1; Figs. 1, 4, 5). By the year 2018, there was a positive correlation of new sites with the number of posted eBird checklists noting the Pearly-eyed Thrasher’s continually increasing presence (R2 = 0.67, P = 0.0002).
More than 100 people have documented the Pearly-eyed Thrasher’s presence on mainland Hispaniola since 1984 (Appendix 1, Table 2). Two-thirds of the Pearly-
Figure 4. Counts of Pearly-eyed Thrasher encounters (sightings and mist nettings) by set- ting (defined as the nature of the surroundings and environment) and locale (geographical location). Settings: CRL (coastal rural; natural habitat); CRT (coastal resort; anthropically altered habitat; for all locales, this includes any combination of natural and manicured green habitat as well as gray habitat, e.g., cement, asphalt, stone and any other non-biotic material associated with hotels, restaurants, adjacent grounds, and all other affiliated infrastructure); CSU (coastal suburbs; a combination of natural and manicured green and gray habitat); IRL (interior rural; natural habitat); IRT (interior resort; a combination of natural and manicured green and gray habitat; and ISU (interior suburbs; a combination of natural and manicured green and gray habitat). Locales: BÁVA (Bávaro, La Altagracia Province); BHIB (Baya- hibe, La Romana Province); HATO (Mayor Province); LABA (Labadie, Haiti, Nord Depart- ment); LAGAL (Las Galeras, Samaná Province); LAROM (La Romana Province); NPAB (Parque Nacional Armando Bermúdez, Santiago Province); PNEST (Parque Nacional Del Este, La Altagracia Province); PUCA (Punta Cana, La Altagracia Province); STDO (Plaza de Cultura and Jardín Botánico, Santo Domingo city, Nacional, Distrito Nacional); STGO (Santiago city, Santiago Province).
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2019 Urban Naturalist No. 23 W.J. Arendt, M.M. Paulino, L.R. Paulino, M.A. Tórrez, and O.P. Lane
eyed Thrasher sightings were from resorts and in the vicinity of hotels (n = 40), with only a third of the sightings originating from suburban or rural communities combined (n = 20). The difference was significant at alpha = 0.05 (proportions test: z = 2.078, P = 0.038). Only 5 sightings were reported from rural areas, 2 from coastal sites within Parque Nacional Del Este, 2 recent (2018) records from the in- terior of Parque Nacional Del Este, and 1 in 2017 from Parque Nacional Armando Bermuda. Most sightings were made within the past 6 years, although there are 2 single records from 1984 and 1995 (Appendix 1, Table 2, Fig. 3). With the excep- tion of September, Pearly-eyed Thrashers have been reported in every month of the year (Fig. 6). Sightings in November, December, and January (n = 47) and March, April, and May (n = 27) account for 74 of the conservative minimum of 85 total sightings and constitute 87% of all sightings (Fig. 6). Very few (or no) sightings were documented during other months, which, in total, constitute half of each year (February and June–October).
Potential points of entry onto mainland Hispaniola by the Pearly-eyed Thrasher
With the exception of a couple of sightings on the northern coast of Haiti, and thus the possibility of a northern point of entry in western Hispaniola from the Bahamas, the kernel UD model has derived a point of concentration at the far eastern end of mainland Hispaniola in 2 municipalities, La Altagracia and La Romana (Fig. 5). These 2 municipalities host important tourism areas such as Punta Cana and several sites in and around La Romana, among others, where resorts and beach destinations are the main attractions.
Figure 5. The Pearly-eyed Thrasher’s probable point of entry onto mainland Hispaniola. The map is based on the division of the Dominican Republic’s 31 provinces and Haiti’s 10 departments, with longitude (west) and latitude (north) in decimal degrees. The legend to the right consists of an incremental scale and color scheme based on the probability of the Pearly-eyed Thrasher’s occurrence, in which white is the probability of non-occurrence (0), gradually intensifying to a solid, dark green, the probability of occurrence of at least one individual (1).
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Discussion
Pearly-eyed Thrasher presence–absence on mainland Hispaniola
In 1807, Vieillot listed the Pearly-eyed Thrasher as an inhabitant of “Saint- Dominique” (Hispaniola) and specifically stated observing the species in Haiti. Additionally, Cory (1891) listed the species from “San Domingo”, and Beebe listed it among 13 species from Haiti (Arendt 2006:appendix 3). However, the museum records of early field collectors are notoriously vague, incomplete, and sometimes incorrect. For example, Wetmore and Swales (1931) state that Beebe’s specimen had no information as to collection locality and was not listed by Beebe a year later in his birds of Haiti.
eBird Sightings are highly correlated with peaks in tourism
That most sightings of the Pearly-eyed Thrasher on Hispaniola are from popular tourist destinations during peak tourism seasons (November–January and March– May), attests to the fact that vacationing, international birders account for the ma- jority of those documenting the Pearly-eye’s presence and apparent colonization of Hispaniola. However, sustained and growing populations must be evident before one can say with confidence that the Pearly-eyed Thrasher has successfully colo- nized Hispaniola and is an established breeding resident of the island.
Most thrashers photographed by “eBirders” were males (Appendix 1). Ad- ditionally, the single thrasher that the current authors banded February 2017 and
Figure 6. Total number of Pearly-eyed Thrashers reported (sightings and mist nettings) each month on mainland Hispaniola.
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subsequently monitored (Table 1) was an adult male and, to date (September 2018), no female has been observed by our study group anywhere in the greater Santo Domingo area. The gender of the Pearly-eyed Thrasher observed in the Botanical Garden in 2009 was not reported (Appendix 1). Still, one study from Puerto Rico suggests that male Pearly-eyed Thrashers tend to disperse farther than females (Arendt 2006:figure 6.6). Additionally, the number of new sites where the Pearly- eyed Thrasher now occurs has increased concomitantly with the number of posted eBird checklists, but it is important to note that even though the number of new sites where the thrasher is now present has increased, the number of new municipalities where the bird now occurs has not increased in a similar fashion, reinforcing the fact most sightings are in municipalities dominated by tourism.
Despite the fact that most thrasher sightings originated from urban and suburban settings along the eastern and southern coasts of Hispaniola and vacation destina- tions frequented by local and international visitors alike, one must use discretion before concluding that the Pearly-eyed Thrasher is found only in, or even favors, anthropogenic habitats. Indeed, as outlined above, often the thrasher’s optimal habitat on several islands throughout its extensive range is densely foliated stands of broadleaf forest at mid- to high elevations. What is needed now is a continued, concerted effort to search for the species throughout the island, especially the in- terior and more remote natural areas; that is, those areas in which the species has not been observed for at least two centuries or so, and as documented by the early literature and substantiated by several avian researchers, birders, and others over the past several decades of study and observation.
Potential points of entry onto mainland Hispaniola by the Pearly-eyed Thrasher
Punta Cana may very well be the initial point of entry by the Pearly-eyed Thrasher onto mainland Hispaniola. This notion is strongly supported by the fact that the first small “resident” population was discovered in the Punta Cana area in 1999 (Keith et al. 2003, Latta et al. 2006). Furthermore, the density of points in Figure 1 and the higher probability of occurrence in Figure 5 clearly demonstrate that the eastern portion of Hispaniola (where Punta Cana and other large resorts are located) is where there is a much higher expectation of observing the species on the main island, with a demonstrably reduced probability towards the center of the island. However, the authors expect sightings in rural and forested areas to increase as the propagule coastal populations disperse inland.
Attributes and inaptitudes of an avian supertramp
Why doesn’t the Pearly-eye generally colonize and successfully compete on the larger islands of the Caribbean (and elsewhere in the region) or in species-rich habitats? Several inherent and extrinsic factors play key roles in the thrasher’s noticeable absence in these situations. One major factor is diffuse (also deemed in- direct or exploitation) competition (Arendt 2006, Schoener 1982), which is defined as any indirect conflict among species usually over obligatory resources such as food or nest sites (Diamond 1975, MacArthur et al. 1972). To its disadvantage, the Pearly-eye is a “jack-of-all-trades, master-of-none” generalist, particularly when
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one considers its holistic diet and near lack of habitat preference. The thrasher eats a wide variety of foods and is found in all major habitats from sea level to mountain summit. Yet, within the relatively small, often restrictive habitats found throughout the thrasher’s insular range, a high density of avian food and foraging specialists inhibits colonization by this generalist supertramp of species-rich large islands and habitats. Consequently, for several hundred years, diffuse competition along with interference competitive pressures, i.e., direct, physical, conflict often related to interspecific competition (Dondt 2012), may have kept the Pearly-eye from gaining a foothold on the once heavily forested, species-rich Hispaniola, which is the second largest island in the Caribbean and 7 times larger than Puerto Rico (Arendt 2006).
Disproving myths
Some argue that the Pearly-eyed Thrasher is an introduced or invasive species (CBT 2018), which is erroneous. It is a bona fide “natural” member of the Carib- bean avifauna. The thrasher’s presence in the Caribbean dates back more than 2000 years. The first evidence of the prehistoric occurrence of the Pearly-eyed Thrasher in the Caribbean comes from an archaeological site (subsequently destroyed by volcanism) located near Trant’s Bay, Montserrat, in the Lesser Antilles (Stead- man et al. 1984a). And fossilized bones of the Pearly-eye have been found in late Holocene deposits from the Burma Quarry, Antigua, Lesser Antilles (Pregill et al. 1988, Steadman et al. 1984b). Both discoveries confirm the thrasher has been in the region and at least proximate to the Greater Antilles for millennia. L.J.P. Vieillot (1807—corrected date 1808; Browning and Monroe 1991) collected the type speci- men of the Pearly-eyed thrasher in Puerto Rico. The type specimen remains in the Vieillot collection at the Musée de Histoire Naturelle in Paris.
Many associate the Pearly-eyed Thrasher with only ephemeral, disturbance-re- lated habitats and human-induced altered lands, e.g., habitats impacted by extreme weather events and anthropic development, because Pearly-eyes are commonly observed, and thrive, in such situations. But in addition to its urban disposition, as a habitat generalist, inhabiting several high-relief islands throughout the Caribbean, the Pearly-eyed Thrasher is frequently the most abundant landbird in the densest stands of broadleaf forest at mid- to high elevations, often comprising up to 60% (relative abundance) of the captures at high elevations in closed-canopy wet forest (Arendt 20006:chapter 4, figure 4.4). Moreover, on Tortola (British Virgin Islands), the Pearly-eye is most abundant in coconut plantations and also at mid- to high elevations, where it is the most numerous landbird in the taller, denser vegetation (Arendt 2006, Mirecki et al. 1977). It even frequents and breeds in bamboo stands in Puerto Rico (Arendt 2006).
Supertramp attributes enhanced through natural and human-induced disturbances
The Pearly-eye’s future as a species depends on its ability to adapt to the ever- changing conditions in natural and anthropogenic environments. The Pearly-eyed Thrasher’s fairly recent stronghold on mainland Hispaniola and its apparent on- going colonization attempt of Hispaniola mirrors that of its earlier promulgation
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throughout the main island of nearby Puerto Rico in response to that island’s ever-increasing urban development. For more than a century, Pearly-eyes were scarce and only patchily distributed in the lowlands and foothills of Puerto Rico. However, by the 1920s, resident biologists noted a steady increase in thrasher num- bers throughout the island. By the 1950s, thrasher populations had burgeoned and virtually covered the island, to elevations of several hundred meters in the Sierra de Luquillo mountains in the northeast (Arendt 2006:68). Arguably, urban devel- opment augmented thrasher populations by creating a plethora of food resources and nest sites for prospecting thrashers undergoing ecological release and niche expansion in a less competitive environment, resulting from reduced interspecific competition. In urban settings, there are fewer species and fewer individuals of each species with whom the Pearly-eye must compete for the vital resources necessary for survival (Arendt 2006:chapter 4).
Climate change as the catalyst for a supertramp’s potential foothold in North America
As the Supertramp Theory predicts (Diamond 1974), Pearly-eyed Thrasher num- bers will increase immediately following disturbance in areas devastated by natural and anthropogenic disasters such as hurricanes, prolonged droughts, deforestation, and urban development. Owing to the mounting effects of global climate change such as increasing number and frequency of heat waves, droughts, heavy precipita- tion and diluvial downpours, floods, deadly hurricanes, and extreme cyclonic events on a global scale, in the Greater Caribbean Basin and the Gulf of Mexico (Don- nelly and Woodruff 2007, Emanuel 2005, Goldenberg et al. 2001, Lugo 2008, NCA 2014), coupled with ever-increasing urban development throughout the region but notably rampant in the northern Caribbean (Arendt 2006: chapter 4, Stenseth et al. 2015) and principally in The Bahamas, it is only a matter of time (and a very short time) before the Pearly-eyed Thrasher reaches the mainland of the United States. Currently, Pearly-eyes are frequently sighted on Nassau and Great Abaco (eBird 2012), both fewer than 300 km from Miami, FL, USA. Once the thrasher reaches Grand Bahama, it is less than a 200-km trek to the US mainland. The growing number of severe cyclonic events laying waste to natural habitats and destroying the metropolitan areas of Florida and other southeastern states will exponentially increase the Pearly-eye’s chances of a successful colonization of the USA mainland in the near future.
Acknowledgments
We thank our colleagues and international birders who have kindly shared their unpub- lished information and, in particular, Chris Rimmer (VCE) for suppling contact information for additional birders, especially in Haiti; and Kent McFarland (VCE and eBird filter man- ager for Hispaniola) for ensuring we found all Pearly-eyed Thrasher eBird sightings through July 2018. We also thank the many “ebirders” who submitted checklists of their Pearly-eyed Thrasher sightings to eBird.org/, as well as Cornell University and its staff for creating the eBird platform and managing it online, thus, making it accessible to the world. We thank Editor Sabina Caula and the 3 anonymous reviewers for their constructive comments.
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We especially thank Jerry Bauer, International Cooperation Program Manager, of the US Forest Service International Institute of Tropical Forestry (USFS-IITF) for technical, administrative and logistical support, and the US Agency for International Development/ Dominican Republic for financial support through a Participation Agency Program Agree- ment (PAPA-AEG-T-00-07-00003) with the USFS-IITF.
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Appendix 1. Summary of Pearly-eyed Thrasher encounters (mist netting and reports by researchers, local residents, and eBirders) on main- land Hispaniola, including location, habitat (rural or urban), date, number reported (some with notes), and source. Numbers of individuals observed are the totals (or “minimum” totals) mist-netted, sighted, or entered in eBirder checklists. Some eBirders, rather than quantify the total number of individuals detected, simply placed an “X” in their checklist. Location and setting, i.e. the place or type of surroundings and environment): CRL (coastal rural); CRT (coastal resort: “resort” for all locales includes hotels, restaurants, adjacent grounds, and as- sociated settings); CSU (coastal suburbs); IRL (interior rural); ISU (interior suburbs)
Location and habitat
Date
Number reported and (notes)
Source
Haiti
Labadie (Nord) (CSU) Labadie (CRT) (Cap-Haitien)
12 November 2011 11 January 2011
1
Douglas Long Jim Zook
Dominican Republic
Hato Mayor (Paraíso Caño Hondo) (IRT) Samaná (Las Galeras) (CRT)
(El Pelícano Apart-Hotel)
La Romana Dreams La Romana Resort (CRT) Parque Nacional Del Este (IRL)
Punta Cana Dreams Resort (CRT)
Hato Mayor (Paraíso Caño Hondo) (IRT)
25 July 2018 23–24 June 2018
1 (“calling extensively”)
1 (heard singing in mango tree)
Eric Baldo
Maximo Marcos Peña Roca, Eladio Fernández)
John Hull
John Hull
Elizabeth Geissler
Adam Winer
Punta Cana Hard Rock Hotel (CRT) Punta Cana Bávaro Beach (CRT)
La Romana Dreams Dominicus (CRT) Bayahibe (Parqueo Principal) (CRT) Parque Nacional Del Este (IRL)
4 March 2018
27 January 2018 20 January 2018 17 January 2018 16 January 2018
9 January 2018
8 January 2018
10 December 2017
1 1 3 2 1 5
Justin Streit
Brian Menker
Daniel Gagné
Robert Ruvolo
Simon Best
Ryan Larson
John Cobb, Julio Salgado David Bernstein
Punta Cana Resort and Club (CRT)
Hato Mayor (Paraíso Caño Hondo) (IRT) Punta Cana (Club Med) (CRT)
31 March 2018 30 March 2018 15 March 2018 14 March 2018
1
1
2
1 (“2 seen prior day at hotel; this individual along the creek.”) 1 (photo of adult female, UCB) 1
1
(“6 in trees behind hut where they outfit and orient people for cable slide ...”)
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Location and habitat
Date
Number reported and (notes)
Source
Parque Nacional Armando Bermúdez (IRL) Punta Cana (Club Med) (CRT)
14 July 2017 15–22 April 2017
1
Jonathan Oliveras
Scott Stafford (party of 3, 20 April)
Punta Cana Ecological Found. (CSU) (Animal Farm)
Punta Cana (Blau Natura Park) (CRT)
16 April: UCBA male;
19 April: UCB male;
22 April: FCF male (singing) 13 April 2017
1 1 1
Marta Curti
Samaná (Las Galeras) (CRT)
21 January 2017 19 January 2017
(wooded area ~100 m SE of the Grand Paradise Resort)
Doris Guimond and Claude Gagnon
Daniel Gagné
(but only a photo of 1 individual)
Santo Domingo Plaza de la Cultura (CSU) Samaná Peninsula (Las Galeras) (CRT) (Amsha Marina and Resort)
8 October 2016 27 March 2016
1
María Milagros Paulino James Holdsworth
Punta Cana (Club Med) (CRT)
25 December 2015
3
(photo of one individual) (adult female, UCB)
2
(“a pair seen together”) (photo of immature female, SCF) 1
1
1
1
Isabel Apkarian
Punta Cana (Club Med) (CRT)
Bávaro (Barceló Palace Deluxe) (CRT) Santiago (Intellisys Corporation) (ISU) Punta Cana Village (CSU)
(near Punta Cana International Airport) La Romana Altos de Chavón (CSU)
12 December 2015 27 May 2015
29 April 2015
14 March 2015
Geoffrey Groom Eduardo Costoya Chris Corcino Stephen Brauning
La Romana 31 Barranca (CSU)
(gsolf cart from hotel to Altos de Chavón)
14 March 2015 11 March 2015
1
(photo of adult male, UCB) 1
John Sullivan John Sullivan
2
(min.) (photos 16, 19, 22 April)
2019 Urban Naturalist No. 23 W.J. Arendt, M.M. Paulino, L.R. Paulino, M.A. Tórrez, and O.P. Lane
22
Location and habitat
Date
Number reported and (notes)
Source
Punta Cana (CRT) Punta Cana (CRT)
18 August 2014 31 May 2014
1
Robert Parsons
María Paulino, Kate Wallace, Danilo Mejilla Andrey Vlasenko
Bávaro Grand Palladium Hotel (CRT) (Playa del Cortecito)
Punta Cana Resort and Club (CSU) (Forest Patch)
22 January 2014 16 January 2014 10 January 2014
2
(“observed near a restaurant”) 1
(2 photos: adult male, UCB) 1
Sarah Dzielski Sarah Dzielski
Punta Cana Village (CSU)
2
(eBird “Breeding Code P”: “Pair in Suitable Habitat”) (“Probable”)” 1
(“seen...in tree above restaurant”) 1
2
1
(“along beach trail near park [HQ]”)
Bayahibe (n. harbour restaurant) (CRT)
9 January 2014
Wesley Hochachka
Bayahibe (Parqueo Principal) (CRT) Parque Nacional Del Este (CRL) Bayahibe Playa Dominicus (CRT)
9 January 2014
21 December 2013 2 December 2013
Mary M. Ferraro Paul Pratt
Freya Uvarova
(Catalonia Gran Dominicus)
Samaná Grand Paradise Beach Res. (CRT) (Playa del Aserradero Las Galeras) Bayahibe (CRT)
3
(min.)
1
(min.) (photo: immature, sex?B)
Jorge Brocca Kevin Hannah Pam Overmyer
Punta Cana Club Med (CRT)
12–14 November 2013
9, 13 November 2013
19, 22–24 May 2013 2
Punta Cana Club Med (CRT)
12 May 2013
(min.) (“seen at 2...locations in [the] resort.”)
Lisa Williams
Punta Cana Resort and Club (CSU) Rancho Punta Cana Boogie (CRT) Punta Cana Ecological Found. (CSU) Punta Cana Resort and Club (CRT)
31 March 2013 12 January 2013 7 January 2013 6 January 2013
2 (“in dense shrubs X 1 1 1
around resort”)
Byron Swift
Mike V.A. Burrell
Tim Healy
Tim Healy and Mary M. Ferraro
2019 Urban Naturalist No. 23 W.J. Arendt, M.M. Paulino, L.R. Paulino, M.A. Tórrez, and O.P. Lane
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Location and habitat
Punta Cana Ecological Found. (CSU)
Date
4, 6 January 2013
Number reported and (notes)
Source
Mary Margaret Ferraro
Punta Cana Village (CSU)
La Romana Dreams Hotel (CRT)
12 January 2012
29, 31 December 2011
1 (min.) 2
Jeffrey Climie Robert Hirst
La Romana Dreams Resort (CRT)
(Playa Bayahibe)
Santo Domingo Jardín Botánico Nacl. (CSU) Punta Cana Club Med (CRT)
Punta Cana (CRT)
(Grounds of the Grand Palladium)
Bávaro Resort)
Punta Cana (CRT)
(grounds of the Grand Palladium)
Bávaro Resort)
Bávaro Beach (CRT)
Punta Cana Iberostar Hotel (CRT)
Punta Cana (CRT)
4 December 2011
2
(“along nature trail...”) 1
X
1
Punta Cana Ecological Reserve (CSU) (forest)
Guaraguao Parque Nacional Del Este (CRL)
25, 26 February
3 February 1984 1
Peter Adhemar
28 June 2009
26 April 2008
16 November 2007
Frank Bingham
Tamie Bulow Caribbean WorldBirds
16 November 2007
X
Ted Goshulak
(min.) (near Punta Cana International Airport)
2
(min.) (2nd day) “2 birds in close vicinity squabbling”)
Gerry McChesney
X
X
4
(“2 inds. obs.”) (to assume that 2 additional thrashers were heard) 23, 25 January 1995 X
Andy Dettling
Andy and Mark Dettling Olivier Langrand
30 May 2003
28 May 2003
20 February 2003
AThrashers in the photos and the mist-netted bird at the Plaza de Cultura were aged and sexed by a coauthor (WJA); ages were determined using molt and age classification codes derived by Wolfe et al. 2010:
FCF (first molt cycle, formative plumage)
(mist-netted in dry forest)
Chandler S. Robbins and Tomás A. Vargas Mora
2019 Urban Naturalist No. 23 W.J. Arendt, M.M. Paulino, L.R. Paulino, M.A. Tórrez, and O.P. Lane
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SCB (second molt cycle, basic plumage)
UCB (unknown molt cycle, basic plumage)
Gender (male, female) was determined by appendicular proportions, plumage differences and soft parts.
BKevin Hannah photo – this immature (FCF) individual retains remnants of a dark eye and fleshy commissure (gape), and it is in formative plumage—note the replaced second alula; the bird most likely hatched in early 2013; it shows “mixed” gender characteristics, although it is possibly an immature male, owing to 3 “male” characters: (1) prominent white malar streak; (2) rudimentary white margins of tertials, greater coverts and tail; (3) solid brown “chevron” pattern in the center of the ventral tract feathers, which contrast highly with their white centers and white feather margins. However, there are two apparent “female” characters, i.e., prominent, bulbous bill, and short tail in proportion to entire body length.