Observation of a Veraguan mango ( Anthracothorax veraguensis ) with male-like plumage providing parental care

Observation of a Veraguan mango ( Anthracothorax veraguensis ) with male-like plumage providing parental care | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 6 June 2025 V1 Latest version Share on Observation of a Veraguan mango ( Anthracothorax veraguensis ) with male-like plumage providing parental care Authors : Dallas Levey 0000-0001-7421-7796 [email protected] and Gretchen C. Daily Authors Info & Affiliations https://doi.org/10.22541/au.174917367.70703478/v1 197 views 170 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Male plumage mimicry by adult females of sexually dimorphic hummingbird species provides an intriguing system for understanding social and ecological selection mechanisms. However, our understanding of female male-mimicry is limited by a lack of behavioral observations of wild hummingbirds with male plumage, such as in giving parental care. Using photos and 2.5 min of video taken at close proximity, we documented a Veraguan mango (Anthracothorax veraguensis) with male plumage both incubating eggs and later feeding young in the town of Palmar Norte in southern Costa Rica. Based on plumage characteristics and range, we ruled out the similar green-breasted mango (A. prevostii) that occurs in close geographic proximity. Using Google Earth imagery, we characterized the landscape surrounding the nest as a heterogeneous mix of urban, residential, and agricultural land. We speculated on potential mechanisms that may maintain female-limited polymorphisms in the Veraguan mango and related species, including the interaction of social and ecological selection pressures. This observation provides the first empirical evidence of male-mimicry polymorphism in the Veraguan mango, contributing valuable information to the species’ natural history and to the broader understanding of male-plumaged females in hummingbirds. Introduction In sexually dimorphic bird species, it is a rare curiosity to find adult males and females in the same plumage. In hummingbirds—where males do not provide parental care and sex can be determined through breeding behavior—previous research has quantified the frequency of female-limited plumage polymorphisms across species (Diamant et al. 2021, Falk et al. 2022). This work demonstrated a nonsexual social selection mechanism of male harassment avoidance, in which adult females avoid potentially detrimental male harassment through male plumage mimicry (Falk et al. 2022). Yet this investigation has been conducted primarily through analyses of museum specimens of hummingbirds (Bleiweiss 1992, 2001, Diamant et al. 2021, Clark et al. 2022), supported by field experiments on two species: white-necked jacobins ( Florisuga mellivora ; Falk et al. 2021, 2022, 2025a) and Anna’s hummingbirds ( Calypte anna ; Clark et al. 2022). A recent study across ~300 hummingbird species assessed museum specimens to quantify the frequency of female-limited plumage polymorphisms, yielding an estimate of ~25% of species (Diamant et al. 2021). However, the difficult task of discerning females with male plumage only from skins, without additional cues for sexing such as observations of female-limited hummingbird behaviors like parental care, has called into question the frequency of female-limited plumage polymorphisms across hummingbirds (Clark 2022, Clark et al. 2022). Using only direct behavioral evidence suggests that individuals with adult male plumage. These species include the white-necked jacobin ( Florisuga mellivora ; Elgar 1978, Schuchmann 1999, Falk et al. 2021), black-chinned hummingbird ( Archilochus alexandri ; Farr and Middleton 2023), green-breasted mango ( Anthracothorax prevostii ; Stiles et al. 1989), and black-throated mango ( A . nigricollis ; Quesnel 1995, Rochford 2012). Of these four species, the two mangoes are the only species with observations of wild birds building nests and providing parental care, including egg incubation and feeding of young (Quesnel 1995). We report photo and video evidence of a male-plumaged Veraguan mango ( Antracothorax veraguensis ) providing parental care in southern Costa Rica. We describe plumage characteristics of the hummingbird, the behaviors recorded in the video, and the landscape context. We then discuss the likelihoods of potential mechanisms to explain the event. Material and methods Study area We observed an adult female with adult male plumage in Palmar Norte, a small town in southern Costa Rica in the Puntarenas province (8° 57’ 55.8”N, 83° 27’ 42.5”W; 32 MSL; Fig. S1). On a landscape scale, Palmar Norte is located north of Río Térraba and at the southern base of a coastal mountain range. Dominant land cover types in the area include urbanized towns, residential gardens, cattle pasture, lowland tropical rainforest patches, and oil palm plantations. We found the nest approximately 5.5 m above ground level, adhered with spider web to a powerline cable running alongside the northern edge of Carretera Costanera Sur and over the exit of a supermarket parking lot. During the observation, semi-truck, car, and motorcycle traffic on Carretera Costanera Sur was constant and loud. The habitat context around the nest location included a mix of paved surfaces, grassy lots, residential gardens, cattle pasture, and live fences of native and nonnative trees. Determining sex, identification, and age For sex determination of the hummingbird, we consider the possibility of an adult male providing parental care unlikely, given the lack of evidence of adult male hummingbirds providing parental care in any hummingbird species (Sibley 1957, Schuchmann 1999). Therefore, we operate under the assumption that the bird is an adult female with adult male plumage. For the species identification, we used range and the characteristics of the male plumage. Phylogenetically, the Veraguan mango is in a clade with the Hispaniolan mango ( A . dominicus ), green-breasted mango, and black-throated mango ( A . nigricollis ; Schmitz-Ornés and Haase 2009, Schuchmann and Boesman 2020). Two species of mango within this clade occur in Costa Rica: the green-breasted mango, which is distributed in the lowlands on both coasts and in the highlands of the Central Valley, and the Veraguan mango, whose northernmost distribution begins near the southern limit of the green-breasted mango and extends along the Pacific lowlands throughout the Osa Peninsula in Costa Rica and into Panama (Ridgley and Gwynne 1989, Garrigues and Dean 2007, Schuchmann and Boesman 2020). The observed nest nesting behavior on a powerline in urban habitat with nearby agricultural land, residential gardens, and some native forest is noted occasionally for the Veraguan mango and other members of Antracothorax , though they typically nest conspicuously high above ground in tall trees at forest edge or isolated in grassy habitats (Garrigues and Dean 2007, Schuchmann and Boesman 2020, Juárez et al. 2024). The key plumage trait separating Veraguan mango from the similar green-breasted mango is the lack of a vertical dark stripe in the center of the blue iridescent color that extends from the throat to the breast (Schuchmann 1999, Stiles et al. 1989, Schuchmann and Boesman 2020, Juárez et al. 2024). Some Veraguan mango males show a small dark green wedge on the throat that rarely extends to the breast like in green-breasted mango (Wetmore 1968, Olson 1993). The hummingbird showed a dark throat color in certain angles that did not appear to extend past the throat to the breast and belly at any angle (Fig. 1-2). For age determination, the plumage lacks the contrasting white belly with a dark central vertical stripe that is typical of immatures mangoes (Stiles et al. 1989). Moreover, its parental care at the nest indicates its maturity (Fig. 1-2). Event description We observed, photographed, and recorded videos (https://doi.org/10.5061/dryad.jh9w0vtp7) of a female Veraguan mango with male plumage incubating eggs and feeding juvenile birds in February 2025 (Fig. 1A). Our first observation on Feb 5 included 45 min of viewing the unattended nest and 5 min of viewing the adult mango perched on the rim of the nest and incubating the eggs (Fig. 1B-C). We did not see the adult tending to the nest structure or adding more materials. We returned to view the nest on Feb 13. We observed two juvenile birds in the nest in a food begging posture with open mouths pointed upwards (Fig. 2A). We observed the unattended juveniles for 28 minutes. After this period, the mother returned and perched on a nearby wire (Fig. 1A). After 3 minutes of resting and preening, the mother flew to the nest and perched on the rim to begin feeding the juveniles (Fig. 2B). In total, the mother spent 1 min and 50 sec in a feeding bout that entailed 8 pauses of 4.1 ± 1 sec each (30% of total time) and 9 feedings of 7.9 ± 2.4 sec each (70% of total feeding bout time). The juvenile on the left side of the mother in the video received 4 full feedings for a total of 35 sec (32% of total time), averaging 8.8 ± 2.2 sec. The juvenile on the right side of the mother received 5 full and 1 partial feeding for a total of 44 sec (40% of total time), averaging 7.3 ± 2.6 sec. For 39 sec after the last feeding, the mother sat perched on the edge of the nest, looking left and right while occasionally reaching around the nest with her bill to grab at a lichen attached to the nest wall or to reach at one of the juveniles (Fig. 2C). Then, the mother flew away from the nest. Fig. 1. Photo series of the female Veraguan mango ( Anthracothorax veraguensis ) with male-like plumage providing parental care (A-B) and an example of a typical adult female Veraguan mango on a nest (C). In photos A and B (taken on Feb 5, 2025), the female is perched on a cable and nest, showing two angles of the plumage. The hummingbird’s overall size and proportions are typical of mangoes, including a long tail, stout, black bill with a downward curvature, and primarily green colored. The tail is mostly maroon with black terminal banding and thin white bordering. The throat is blue and darkest in a wedge-shaped area that is restricted to the throat. In photo C (taken on Sept. 30, 2024, near Ciudad Neily, Costa Rica), we provide a photo of an adult Veraguan mango with typical adult female plumage to demonstrate the plumage differences, including the contrasting white undersides with a dark vertical stripe down the throat. Fig. 2. Photo series of the female Veraguan mango ( Anthracothorax veraguensis ) with male-like plumage (in Fig. 1A-B) feeding young in the outskirts of Palmar Norte, Costa Rica. Photos 2A-C (taken Feb 13, 2025) show the juvenile birds in begging posture and being fed. Photo 2C shows the mother on the rim of the nest with the two juveniles and provides a close-up view of the underside plumage, including the blue throat color. Discussion Our report of a hummingbird with male plumage providing parental care represents firm evidence of female-limited adult plumage polymorphism in a new species, joining two other species in the Anthracothorax genus with past evidence of male-plumaged birds providing parental care (Stiles et al. 1989, Quesnel 1995, Rochford 2012, Juárez et al. 2024). Mechanistically, the maintenance of female-limited polymorphisms in a population requires frequency-dependent or neutral balancing selection in ecological and social contexts (Falk et al. 2025b). We speculated on frequency-dependent balancing selection mechanisms given the robust evidence for social drivers of female-limited polymorphisms in the white-necked jacobin (Falk et al. 2021, Falk et al. 2025b). We considered hypothetical mechanisms involving male harassment avoidance (Falk et al. 2021) in older hummingbirds and its interaction with interspecific competition for feeding and nesting resources and variable predation rates of females with male plumage and their nests across their nesting habitats. Life-history tradeoff Falk et al. (2021) demonstrated that male harassment avoidance drove the occurrence of female-limited plumage polymorphisms in the white-necked jacobin. In our case, the hummingbird may employ an adaptive strategy to reduce male harassment over time through hormonal changes that trigger the expression of male-like plumage. Previous studies have documented how hormonal changes over time in adult females led to the expression of partial male plumage, including in the red-backed fairywren Malurus melanocephalus (e.g., partial attainment of male-like coloration and morphology; Lindsay et al. 2016), bobolink Dolichonyx oryzivorus (partial attainment of male plumage; Perlut 2008), and pied flycatchers Ficedula hypoleuca (e.g., attainment of male-like white color patches; Morales et al. 2007). If these hormonal changes allowed for successful rearing of young (Clark 2022, Farr and Middleton 2023), a life history tradeoff between maternal investment in herself at a younger age and investment in one of her last potential clutches could explain an adaptive mechanism for some birds in a population to attain male plumage at an older age. In this scenario, younger females would retain female plumage to maximize breeding opportunities, while older females might benefit from a shift to male-like plumage to reduce male harassment at the cost of future mating opportunities. Reduced male harassment may increase the chances of successfully raising their current clutch by enhancing the mother’s ability to forage, feed young, and establish nesting sites. Interestingly, however, Falk et al. (2021) found no link between age and male-like plumage in female white-necked jacobins, concluding instead that such plumage appears after a post-juvenile molt in that species. Social and ecological mechanisms The breeding natural history of species in Anthracothorax includes conspicuous nesting in tall trees at forest edges or in open grassy habitats such as savannahs and cattle pastures (Stiles et al. 1989). Small portions of Anthracothorax populations utilize urbanized areas for nesting, however, such as power lines in towns (Juárez et al. 2024). Such urban areas could present favorable conditions for raising young (Reynolds et al. 2019), especially if interspecific competition for foraging and nesting resources is reduced when hummingbirds with similar foraging and nesting ecology are filtered out of urban habitats (Maruyama et al. 2019, Levey et al. 2021, 2025). Before widespread land-use change throughout Anthracothorax distributions, mothers with relatively conspicuous male plumage may have drawn more attention to predators while foraging and nesting, especially in natural and rural contexts where native predator species are more abundant (Stiles 1978, Levey et al. 2021). More predators in these contexts may have exerted higher nest predation pressure than current predation rates in highly urban areas (Levey and MacGregor-Fors 2024). Female mangoes with male plumage that nest in urban areas may benefit from reduced male harassment and reduced exposure to predation pressures compared to birds that nest in more natural contexts. In this scenario, the frequency of the female-limited polymorphism would be limited by flowering resources and any negative impacts of nesting in highly urbanized areas, such as window collisions, reduced availability of natural insect prey and nectar sources, noise, pollution, and human manipulation of nests (Reynolds et al. 2019, Levey et al. 2024). Despite the uncertainty of the underlying mechanism, our observation contributes valuable natural history information for the Veraguan mango and empirical evidence of a species with a female-limited polymorphism. 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Veraguan mango ( Anthracothorax veraguensis ), ver. 1.0. – In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D. A. and de Juana, E. (eds.), Birds of the World . Cornell Lab of Ornithology. Sibley, C. G. 1957. The evolutionary and taxonomic significance of sexual dimorphism and hybidization in birds. – Condor 59 : 166–191. Stiles, F. G. 1978. Possible specialization for hummingbird-hunting in the tiny hawk. – Auk 95 : 550–553. Stiles, F. G., Skutch, A. F. and Gardner, D. 1989. A guide to the birds of Costa Rica . –Cornell University Press. Wetmore, A. 1968. The birds of the Republic of Panamá. Part 2. Columbidae (pigeons) to Picidae (woodpeckers). – Smithsonian Institution Press. Information & Authors Information Version history V1 Version 1 06 June 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords costa rica female-limited polymorphism male mimicry nonsexual social selection trochilidae Authors Affiliations Dallas Levey 0000-0001-7421-7796 [email protected] Stanford University Department of Biology View all articles by this author Gretchen C. Daily Stanford University Department of Biology View all articles by this author Metrics & Citations Metrics Article Usage 197 views 170 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Dallas Levey, Gretchen C. Daily. Observation of a Veraguan mango ( Anthracothorax veraguensis ) with male-like plumage providing parental care. Authorea . 06 June 2025. DOI: https://doi.org/10.22541/au.174917367.70703478/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . Format Please select one from the list RIS (ProCite, Reference Manager) EndNote BibTex Medlars RefWorks Direct import Tips for downloading citations document.getElementById('citMgrHelpLink').addEventListener('click', function() { popupHelp(this.href); return false; }); $(".js__slcInclude").on("change", function(e){ if ($(this).val() == 'refworks') $('#direct').prop("checked", false); $('#direct').prop("disabled", ($(this).val() == 'refworks')); }); Cited by Dallas R. Levey, Gretchen C. Daily, Male‐Like Plumage in an Urban Nesting Veraguan Mango: Evidence of a Female‐Limited Polymorphism?, Ecology and Evolution, 15 , 9, (2025). https://doi.org/10.1002/ece3.72071 Crossref Loading... View Options View options PDF View PDF Figures Tables Media Share Share Share article link Copy Link Copied! Copying failed. 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