Range Expansion and Breeding of White-cheeked Duck (Anas bahamensis) in the High Andes

Abstract

We review the distribution of White-cheeked Duck Anas bahamensis rubrirostris in mainland Ecuador and show that the species is expanding its range significantly. Contrary to published records, A. b. rubrirostris has been present in mainland Ecuador at least since the early 20th century, although probably in low numbers. During the 20th century, the species increased its range along the entire coastlands of Ecuador and nowadays, it has reached the coasts of Colombia. The species has also extended its presence along the Andes, and we report the first breeding records of A. b. rubrirostris in the Andes at altitudes between 2360 and 2440 m, the highest across the entire range of the species. We describe the transitioning plumage between duckling and juveniles, which has not been portrayed in detail before.

Full text

1
1
Range Expansion and Breeding of White-cheeked Duck (Anas bahamensis) 1
in the High Andes 2
3
DIEGO F. CISNEROS-HEREDIA1,2,3,4*, MIRJAYA IZURIETA1, EMILIA PEÑAHERRERA,1,2 AND 4
MAARTJE MUSSCHENGA4,5 5
1 Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales, 6
Quito 170901, Ecuador 7
2 Universidad San Francisco de Quito USFQ, Instituto de Biodiversidad Tropical iBIOTROP, 8
Museo de Zoología & Laboratorio de Zoología Terrestre, Quito, Ecuador 9
3 Instituto Nacional de Biodiversidad INABIO, Quito, Ecuador 10
4 Colectivo ciudadano AvesQuito, Quito, Ecuador 11
5 Universidad Central de Ecuador, Facultad de Filosofía, Carrera de Pedagogía de las 12
Ciencias Experimentales Química y Biología, Quito, Ecuador 13
* Corresponding author; e-mail: diego.cisnerosheredia@gmail.com. ORCID: 0000-0002-14
6132-2738 15
16
Abstract.—We review the distribution of White-cheeked Duck Anas bahamensis 17
rubrirostris in mainland Ecuador and show that the species is expanding its range 18
significantly. Contrary to published records, A. b. rubrirostris has been present in mainland 19
Ecuador at least since the early 20th century, although probably in low numbers. During the 20
20th century, the species increased its range along the entire coastlands of Ecuador and 21
nowadays, it has reached the coasts of Colombia. The species has also extended its presence 22
along the Andes, and we report the first breeding records of A. b. rubrirostris in the Andes at 23
altitudes between 2360–2440 m, the highest across the entire range of the species. We 24
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

2
2
describe the transitioning plumage between duckling–juveniles, which has not been portrayed 25
in detail before. 26
27
Keywords.—Anatidae, Anseriformes, distribution, Ecuador, nesting, plumage, urban 28
water reservoirs. 29
30
31
White-cheeked Duck (Anas bahamensis) is widespread but spottily distributed across the 32
Caribbean and South America, where it mainly inhabits brackish waters, mangrove swamps, 33
tidal creeks, estuaries, coastal lagoons, and inland freshwater wetlands, including reservoirs 34
and sewage ponds (Kear 2005, Erize et al. 2006, Johnsgard 2010, Carboneras and Kirwan 35
2020). Until the 20th century, highland regular records of A. bahamensis were only known at 36
Lake Alalay, Bolivia (2550 m), and accidental reports at 3700 m at Lake Poopó, Bolivia, and 37
at 4080 m in Junín, Peru (Bond and Meyer de Schauensee 1943; Fjeldså 1985; Fjeldså and 38
Krabbe 1990). Since the late 20th century, the species has started to disperse into the Andean 39
highlands of Colombia, Ecuador, and Peru (Schulenberg et al. 2007; Freile et al. 2013; 40
Astudillo et al. 2015; Freile et al. 2019a; Rodrıguez-Villamil and Álvarez-Moya 2020). 41
42
Three subspecies of Anas bahamensis are currently recognized: A. b. bahamensis 43
inhabiting the Caribbean and northern Atlantic coasts of South America, south to Brazil; A. b. 44
galapagensis, endemic to the Galapagos Archipelago; and A. b. rubrirostris from the Pacific 45
coasts and Southern Cone of South America (Kear 2005; Johnsgard 2010; Carboneras and 46
Kirwan 2020). Most information on the breeding biology of A. bahamensis is based on data 47
from A. b. bahamensis (Sorenson 1992; Sorenson et al. 1992; Kear 2005; Johnsgard 2010; 48
Davis et al. 2017). Accounts about the southern Anas b. rubrirostris report that nesting occurs 49
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

3
3
from April–September along the coasts of Ecuador (Marchant 1958, 1960; RSOLAB7 2020), 50
October–November in Argentina (Kear 2005), and November–February in Chile (Saratscheff 51
et al. 1991; Tala and Gabella 1991; Vilina 1995; Rubio C. 1998). 52
53
Knowledge on the distribution and breeding of many Ecuadorian waterbird species is 54
scarce, and breeding data has usually been inferred from studies from other areas. Herein, we 55
review the distribution range of Anas bahamensis rubrirostris in Ecuador and report the first 56
breeding records in the high Andes of South America. 57
58
METHODS 59
We made field observations during citizen science activities run by AvesQuito, a citizen 60
collective that promotes bird watching and urban bird ecology studies, and research projects 61
of Universidad San Francisco de Quito USFQ. We have periodically birdwatched since 2010 62
at the Cumbayá Reservoir, Quito Metropolitan District, province of Pichincha, Ecuador (-63
0.19483º, -78.42912º, 2360 m) and since 2014 at the Guangopolo Reservoir, Quito 64
Metropolitan District, province of Pichincha, Ecuador (-0.26927° -78.45366°, 2440 m), 65
especially for Quito’s Christmas Bird Count (Cisneros-Heredia et al. 2015). Intensive bird 66
censuses were carried out every two weeks between April and September 2015 at the 67
Cumbayá Reservoir and between 2019 and 2020 at the Guangopolo Reservoir. 68
69
We obtained occurrence data from mainland Ecuador from different sources. Published 70
records were synthesized based on a literature review, not limited by study type, study 71
design, or language, conducted in Google Scholar™ scholarly text search 72
(https://scholar.google.com) by online searches. We gathered relevant references using the 73
search terms ‘Anas bahamensis’. Open metadata for all occurrences from mainland Ecuador 74
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

4
4
were downloaded from eBird (https://ebird.org) by Cornell Lab of Ornithology (eBird 2020) 75
and iNaturalist (https://www.inaturalist.org) by California Academy of Science and National 76
Geographic (GBIF 2021). Data search and extraction from all sources were conducted in 77
March 2020 and updated in April 2021. For each occurrence point, we compiled geographic 78
data and all other associated information. Protocol for data curation and mining included 79
validation of localities and duplicate detection. All localities were reviewed and validated 80
individually, and coordinates were amended when incorrectly georeferenced in the source. 81
Geographic records of Anas bahamensis from mainland Ecuador used for this paper are 82
available in the Supplementary Material. 83
84
RESULTS 85
Marchant (1958, 1960) recorded several Anas bahamensis (rubrirostris) between 1954–86
1957 in the Santa Elena Peninsula, south-western Ecuador, the first published record in the 87
country (Ridgely and Greenfield 2001). However, an adult male A. b. rubrirostris collected at 88
the Santa Elena Peninsula on 22 December 1933 (by Philip Hershkovitz and deposited at the 89
bird collection of Museum of Zoology, University of Michigan; UMMZ 91899, GBIF 2021) 90
provides evidence that the species has been present on the coast of Ecuador at least since the 91
early 20th century—though probably rare based on the lack of collections by expeditions 92
visiting the area during the late 19th century (Chapman 1926). Interestingly, A. bahamensis 93
was the most abundant duck at La Carolina, a late Pleistocene site in the Santa Elena 94
Peninsula (Campbell, Jr. 1976), suggesting that the species’ abundance has fluctuated in the 95
region, most probably due to environmental changes. 96
97
During the 20th century, A. bahamensis rubrirostris increased its range along the Pacific 98
coastlands of Ecuador, becoming locally common below 50 m and evaluated as a non-99
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

5
5
threatened subspecies in the country (Ridgely and Greenfield 2001, Santander et al. 2013, 100
Freile and Restall 2018, Freile et al. 2019b, eBird 2020, GBIF 2021). There are few inland 101
records on the western lowlands of Ecuador, mainly on the floodplains and rice paddies 102
between Quevedo and Guayaquil (Fig 1) (eBird 2020, GBIF 2021). Ridgely and Greenfield 103
(2001) reported the northernmost Ecuadorian locality of the species in Atacames, province of 104
Esmeraldas, where it has been observed since the 1990s. Solano-Ugalde et al. (2009) 105
evidenced that the species kept advancing north, observing it just 40 km S from the 106
Colombian border (Fig. 1). Anas bahamensis was unknown from the Pacific coasts of 107
Colombia until 2013, when Calderón et al. (2013) reported it from the Mar Agrícola farm, in 108
the department of Nariño, ca. 27 km from the Ecuadorian border. Subsequently, there are 109
records of the species up to Buenaventura, department of Valle del Cauca, Colombia, since 110
2015 (eBird 2020). 111
112
The first high altitude reports of A. bahamensis in Ecuador was at La Mica Lagoon (3900 113
m) in 2002 (Lock et al. 2003), where it was recorded again in 2005 and 2006 (eBird 2020, 114
GBIF 2021). Subsequently, it has been recorded at several highland wetlands, including (only 115
first record cited): Cumbaya reservoir (2360 m elevation) in 2009 (Freile et al. 2013); 116
Llaviucu lagoon, Cajas National Park (3160 m) in 2009 (Astudillo et al. 2015); El Paraiso 117
park (2490 m) in 2009 and Ucubamba reservoir (2415 m) in 2012 (Astudillo Webster and 118
Siddons 2013); Quito Airport pond (2350 m) in 2015 (Boyla and Sanchez 2015); Guangopolo 119
reservoir (2440m ) in 2017 (Bedoya 2017); Colta lagoon (3310) in 2017 (Morocho 2017); El 120
Salado lagoon (2780 m) in 2017 and Yaguarcocha lagoon (2200 m) in 2018 (Loaiza 121
Bosmediano 2017; Freile et al. 2019a), Jipiro park (2030 m) in 2018 (Hefty 2018), and 122
Yambo lagoon (2600 m) in 2020 (Fattorelli 2020). Records of Anas bahamensis across the 123
Andean highlands of Ecuador are becoming more recurrent. The species is present year-124
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

6
6
round in low numbers at the Cumbaya, Guangopolo and Ucubamba reservoirs and the 125
artificial ponds of El Paraíso Park and Museo Pumapungo (pers. obs.; eBird 2020, GBIF 126
2021). 127
128
Figure 1. Map of Ecuador showing the distribution range of White-cheeked Duck Anas 129
bahamensis rubrirostris. White dots: Records until the late 1990s. Black dots: Records since 130
the early 2000’s, showing the range expansion towards the northern coast, inland western 131
lowlands, and Andean highlands. Yellow dots: New highest breeding records. 132
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

7
7
On 26 June 2015, a female A. bahamensis was observed with eight ducklings swimming in 133
the southern pool of the Cumbaya reservoir (Fig. 2). Ducklings were still covered by down 134
but transitioning to juvenile plumage: face grayish-cream, superciliary band grayish-cream 135
and faint, dark line from eye to nape diffuse, foreneck dark gray, cheeks whitish, lines on 136
sides of back whitish and soft, ventral surfaces whitish with faint lateral stripes, bill bluish 137
gray with light pink wash at the base, eyes brown (Fig. 2). The female and her offspring were 138
either preening or swimming between the northern and southern pools until 06 August 2015. 139
During mid-August, the northern pools were cleaned for sediment removal, and the juveniles 140
were not seen subsequently, but three adults were observed regularly. 141
142
Between 13–16 November 2019, a female A. bahamensis with two ducklings were 143
swimming in a narrow channel, part of the Guangopolo reservoir. On 17 November 2019, 144
two adults were sitting on the channel wall, but there was no trace of the ducklings, and they 145
were not seen subsequently. On 15 July 2020, an adult female with eight ducklings covered 146
by down were swimming in the same channel of the Guangopolo reservoir as in November 147
2019 (Fig. 3). Duckling plumage is overall the same as described by Carboneras and Kirwan 148
(2020) and Kear (2005). However, lines on the back were yellow, not whitish, especially in 149
the younger ducklings, and there was a brown spot under the eye line, also more visible in the 150
younger ducklings. By 30 July 2020, ducklings were transitioning to juvenile plumage, but 151
the face, cheeks and neck were still yellow, although drabber than in ducklings (Fig. 3). On 152
04 August 2020, the reservoir was cleaned for sediment removal, and the ducklings were not 153
seen anywhere. On 23 August 2020, the reservoir’s water level was average again, and nine 154
A. bahamensis were observed. All ducks had adult size, but bill and plumage were not as 155
bright as in adults suggesting they were juveniles. Their head was smaller and less round, 156
head plumage looked a bit fluffy or downy, and the base of the bill was narrow and ended 157
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

8
8
wider, whereas, in adults, the width of the bill seemed more constant. On 04 September 2020, 158
two juveniles (bill and plumage less bright than adult) were swimming next to each other in 159
the channel. In October 2020, two or three adults and up to five juveniles were in the 160
reservoir (Fig. 3). Subsequently, 8–15 A. bahamensis were regular at the Guangopolo 161
reservoir until December 2020, suggesting that the juveniles stayed. 162
163
164
Figure 2. Adult female and eight ducklings of White-cheeked Duck Anas bahamensis 165
rubrirostris at the Cumbaya reservoir, Quito Metropolitan District, province of Pichincha, 166
Ecuador, on 26 June 2015. 167
168
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

9
9
169
170
Figure 3. Adult female and eight ducklings of White-cheeked Duck Anas bahamensis 171
rubrirostris at the Guangopolo reservoir, Quito Metropolitan District, province of Pichincha, 172
Ecuador, 15 July 2020 (upper) and 30 July 2020 (lower). 173
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

10
10
174
Figure 4. Juvenile of White-cheeked Duck Anas bahamensis rubrirostris at the Guangopolo 175
reservoir, Quito Metropolitan District, province of Pichincha, Ecuador, 01 October 2020. 176
177
DISCUSSION 178
These are the highest breeding records of A. bahamensis across its distribution and 179
evidence that the species may be starting to establish self-sustaining populations in the 180
Andean highlands. Reproductive biology was within the reported ranges for brood size, 181
parental care, and fledging time (Kear 2005; Carboneras and Kirwan 2020). Breeding 182
seasonality in the Andes of Ecuador mostly coincides with that reported along the coastlands 183
(April-September), although we also recorded a breeding event in November. All breeding 184
records or long-standing populations in the Andes are in human-made wetlands, probably due 185
to lower impacts by human disturbances, lower predation by domestic and feral dogs and cats 186
(since access to all reservoirs and artificial ponds is controlled), and relatively constant water 187
levels. 188
189
190
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

11
11
ACKNOWLEDGEMENTS 191
We would like to thank Empresa Eléctrica Quito EEQ for the permission to access 192
Cumbaya and Guangopolo reservoirs; all members and citizen scientists of AvesQuito for 193
their enthusiastic and constant support; Universidad San Francisco de Quito USFQ, Instituto 194
iBIOTROP, Museo de Zoología and Laboratorio de Zoología Terrestre for logistical and 195
financial support; and xx reviewers for the comments on the manuscript. This paper was 196
possible thanks to the contribution of a wealth of naturalists continuously contributing to 197
eBird and iNaturalist; to scientific collections publishing their curated catalogues in GBIF, 198
and to the Biodiversity Heritage Library for making important literature freely available. This 199
work was supported by Universidad San Francisco de Quito USFQ through research projects 200
(HUBI ID 33 “Diversidad, historia natural, biogeografía y conservación de las aves del 201
Ecuador”, 35 “Estudio de la biodiversidad en áreas urbanas y rurales”, 1057 “Impact of 202
habitat changes on the biological diversity of the northern tropical Andes”, 5452 “Estrés en 203
aves en matrices urbano-rurales en los Andes tropicales”); outreach projects (HUBI ID 278, 204
292, 483, 607 “Celebrando la Naturaleza: Ciencia ciudadana y educación Ambiental para 205
valorar la biodiversidad”), and operative funds assigned to Instituto iBIOTROP, Museo de 206
Zoología and Laboratorio de Zoología Terrestre. 207
208
LITERATURE CITED 209
Astudillo PX, Tinoco BA, Siddons DC. 2015. The avifauna of Cajas National Park and 210
Mazán Reserve, southern Ecuador, with notes on new records. Cotinga 37: 2–12. 211
Astudillo Webster P, Siddons DC. 2013. Avifauna de Santa Ana de los Cuatro Ríos de 212
Cuenca. Comisión de Gestión Ambiental de Cuenca, Municipalidad de Cuenca, 213
Universidad del Azuay, Cuenca, Ecuador. 214
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

12
12
Bedoya J (2017) eBird Checklist - 29 Jan 2017 - Reservorio Guangopolo - 35 species. eBird. 215
https://ebird.org/checklist/S34043296. Accessed 10 Apr 2021 216
Bond J, Meyer de Schauensee R (1943) The Birds of Bolivia. Part II. Proceedings of the 217
Academy of Natural Sciences of Philadelphia. 95:167–221 218
Boyla KA, Sanchez M (2015) eBird Checklist - 5 Dec 2015 - Quito airport pond - 16 species. 219
In: eBird. https://ebird.org/checklist/S26138606. Accessed 10 Apr 2021 220
Calderón JJ, Rosero Y, Ramírez F, et al (2013) Nuevos registros de aves para Nariño y su 221
costa Pacífica. Boletín GAICA 4:5–10 222
Campbell, Jr. KE (1976) The Late Pleistocene Avifauna of La Carolina, Southwestern 223
Ecuador. Smithsonian Contributions to Paleobiology 27:155–168 224
Carboneras C, Kirwan GM (2020) White-cheeked Pintail (Anas bahamensis). Birds of the 225
World version 1.0 226
Chapman FM (Frank M (1926) The distribution of bird-life in Ecuador: a contribution to a 227
study of the origin of Andean bird-life. Bulletin of the AMNH 55: 1–784. 228
Cisneros-Heredia DF, Amigo X, Arias D, et al (2015) Reporte del 1er Conteo Navideño de 229
Aves de Quito, Ecuador. ACI Avances en Ciencias e Ingenierías 7(2): 37–51. 230
https://doi.org/10.18272/aci.v7i2.256 231
Davis JB, Vilella FJ, Lancaster JD, et al (2017) White-cheeked Pintail duckling and brood 232
survival across wetland types at Humacao Nature Reserve, Puerto Rico. The Condor 233
119:308–320. https://doi.org/10.1650/CONDOR-16-169.1 234
eBird (2020) eBird: An online database of bird distribution and abundance [web application]. 235
Cornell Lab of Ornithology, Ithaca, NY 236
Erize F, Rodríguez Mata J, Rumboll M (2006) Birds of South America: non-passerines: rheas 237
to woodpeckers. Princeton University Press, Princeton, NJ. 238
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

13
13
Fattorelli C (2020) eBird Checklist - 30 Jan 2020 - Laguna de Yambo - 28 species. eBird. 239
https://ebird.org/checklist/S63939210. Accessed 10 Apr 2021. 240
Fjeldså J (1985) Origin, Evolution, and Status of the Avifauna of Andean Wetlands. 241
Ornithological Monographs 36: 85–112. 242
Fjeldså J, Krabbe N (1990) Birds of the high Andes: a manual to the birds of the temperate 243
zone of the Andes and Patagonia, South America. Zoological Museum, University of 244
Copenhagen, Copenhagen, Denmark. 245
Freile J, Restall R (2018) Birds of Ecuador. Bloomsbury Publishing, London, UK. 246
Freile J, Solano-Ugalde A, Brinkhuizen D, et al (2019a) Fourth report of the Committee for 247
Ecuadorian Records in Ornithology (CERO) and a revision of undocumented and 248
erroneous records in the literature. Revista Ecuatoriana de Ornitología 5:52–79. 249
https://doi.org/10.18272/reo.vi5.1277 250
Freile JF, Ahlman R, Brinkhuizen DM, et al (2013) Rare birds in Ecuador: first annual report 251
of the Committee of Ecuadorian Records in Ornithology (CERO). ACI Avances en 252
Ciencias e Ingenierías (Quito) 5: 24–41. https://doi.org/10.18272/aci.v5i2.135 253
Freile JF, Santander T, Jiménez-Uzcátegui G, et al (2019b) Lista Roja de las Aves del 254
Ecuador. Ministerio del Ambiente, Aves y Conservación, Comité Ecuatoriano de 255
Registros Ornitológicos, Fundación Charles Darwin, Universidad del Azuay, Red Aves 256
Ecuador, Universidad San Francisco de Quito USFQ, Quito, Ecuador. 257
GBIF (2021) GBIF Occurrence Download [Anas bahamensis Linnaeus, 1758 Ecuador eBird 258
& iNaturalist]. DOI: 10.15468/DL.WHGPND 259
Hefty J (2018) eBird Checklist - 9 Dec 2018 - Jipiro Park - 5 species. eBird. 260
https://ebird.org/checklist/S50973338. Accessed 10 Apr 2021 261
Johnsgard PA (2010) Ducks, geese, and swans of the world. University of Nebraska-Lincoln 262
Libraries, Lincoln, NE. 263
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

14
14
Kear J (ed) (2005) Ducks, geese, and swans. Oxford University Press, Oxford, UK. 264
Loaiza Bosmediano JM (2017) eBird Checklist - 9 Jul 2017 - Laguna El Salado - 8 species. 265
eBird. https://ebird.org/checklist/S38069818. Accessed 10 Apr 2021 266
Marchant S (1958) The birds of the Santa Elena Peninsula, S.W. Ecuador. Ibis 100:349–387. 267
https://doi.org/10.1111/j.1474-919X.1958.tb00404.x 268
Marchant S (1960) The breeding of some S.W. Ecuadorian birds. Ibis 102(4):584–599 269
Morocho T (2017) eBird Checklist - 21 Jan 2017 - Laguna de Colta - 15 species. eBird. 270
https://ebird.org/checklist/S34119540. Accessed 10 Apr 2021 271
Ridgely RS, Greenfield PJ (2001) The birds of Ecuador. Comstock/Cornell Paperbacks, 272
Cornell University Press, Ithaca, NY. 273
Rodrıguez-Villamil DR, Álvarez-Moya WA (2020) Distribución y nuevos registros del Pato 274
Cariblanco (Anas bahamensis) en Colombia. Boletín SAO 29:6–13 275
RSOLAB7 (2020) White-cheeked Pintail (Anas bahamensis). iNaturalist. 276
https://www.inaturalist.org/observations/60418827. Accessed 10 Apr 2021 277
Rubio C. M (1998) Nidificación de pato gargantillo (Anas bahamensis) en la Región 278
Metropolitana. Boletín Chileno de Ornitología 5:30–31 279
Santander T, Ágreda A, Lara A (2013) Censo Neotropical de Aves Acuáticas Ecuador 2008–280
2012. Aves y Conservación, Quito, Ecuador. 281
Saratscheff P, Gabella JP, Tala C (1991) Un breve recorrido por algunos humedales costeros 282
de la V región. Boletín Informativo Unión de Ornitólogos de Chile UNORCH 11:16–17 283
Schulenberg TS, Stotz DF, Lane DF, et al (2007) Birds of Peru, Revised and updated edition. 284
Princeton University Press, Princeton, NJ. 285
Solano-Ugalde A, Freile JF, Moscoso P, Prieto-Albuja F (2009) New and confirmative bird 286
records from northern Esmeraldas province, Ecuador. Cotinga 31: 115–118. 287
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint

15
15
Sorenson LG (1992) Variable Mating System of a Sedentary Tropical Duck: The White-288
Cheeked Pintail (Anas bahamensis bahamensis). The Auk 109:277–292. 289
https://doi.org/10.2307/4088196 290
Sorenson LG, Woodworth BL, Ruttan LM, McKinney F (1992) Serial monogamy and double 291
brooding in the White-cheeked (Bahama) Pintail Anas bahamensis. Wildfowl 43:156–159 292
Tala C, Gabella JP. 1991. Observaciones breves. Boletín Informativo Unión de Ornitólogos 293
de Chile UNORCH 12:9–10 294
Vilina Y (1995) Residencia, abundancia y preferencia de habitat del pato gargantilla (Anas 295
bahamensis) en el humedal “Estero el Yali”, Chile central. Anales del Museo de Historia 296
Natural de Valparaíso 23:89–94. 297
298
299
.CC-BY 4.0 International licenseavailable under a
was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made
The copyright holder for this preprint (whichthis version posted July 18, 2022. ; https://doi.org/10.1101/2022.07.17.499834doi: bioRxiv preprint