Plumage Research Articles

Flirting with danger: predation risk interacts with male condition to influence sexual display

AbstractSexual signaling coevolves with the sensory systems of intended receivers; however, predators may be unintended receivers of sexual signals. Conspicuous aerial displays in some species may place males at high risk of predation from eavesdropping predators. There are three different hypotheses to explain how signaling males can deal with increased predation risk: (1) males invest in survival by decreasing signal conspicuousness; (2) males invest in reproduction by increasing signal conspicuousness; and (3) male response is condition-dependent according to his residual reproductive value. Here, we used blue-black grassquits (Volatinia jacarina) to test these hypotheses, asking whether males modify leap displays under different levels of predation risk. Grassquit males develop an iridescent nuptial plumage and spend considerable time emitting a multimodal signal: while leaping from a perch, males clap their wings above their heads and emit a high-pitched short song. We exposed males to predator and nonpredator playbacks while video recording their displays. We found interactions between predation risk and 2 male condition variables (ectoparasite infestation and proportion of nuptial plumage coverage) that influenced display behavior. Less parasitized males and those with higher proportion of nuptial plumage showed no change in display behavior, while more parasitized males and those with lower proportion of nuptial plumage increased the vigor of displays under predation risk. In other words, males with low residual reproductive value increased reproductive effort when there was a high risk of extrinsic death. Our study provides some empirical support for the terminal investment hypothesis.

Caracterización morfológica de la gallina criolla de traspatio de la subregión Sabana departamento de Sucre (Colombia)

Objetivo. Caracterizar morfométrica y faneróptica de la gallina Criolla de traspatio de la subregión Sabana, departamento de Sucre (Colombia). Materiales y métodos. Se evaluaron 520 animales adultos criollos (350 gallinas y 170 gallos), en el periodo 2017-2018, ubicados en 10 localidades de la subregión Sabanas del departamento de Sucre Colombia. Se recolectó la información en un formato de encuesta integrado por variables cuantitativas y cualitativas. Los datos obtenidos fueron sometidos a análisis descriptivos univariado para muestras independiente. Además, se empleó la técnica de análisis de varianza. Las comparaciones entre machos y hembras se realizaron mediante una prueba de t. Los análisis fueron realizados usando paquete estadístico R. Resultados. Los descriptores analizados mostraron superioridad de los gallos sobre las gallinas (p<0.05). El análisis de varianza en la población de hembras con respecto al peso, determinó que existen diferencias significativas (p<0.05). Las características morfológicas y fanerópticas estudiadas, describen un ave de metatarso amarillo, con color de plumaje que combinan tonalidades marrones, negras, gris y blanco, la morfología y distribución de las plumas en la mayoría de las aves es de característica normal (lisa típica), con distribución uniforme a lo largo del cuerpo, aunque se pueden encontrar ejemplares con patrones de plumaje diferente. Conclusiones. Se pudo observar una amplia variación entre animales procedentes de las 10 localidades estudiadas. Se evidencia una diferenciación tipológica con relación al peso y al tamaño del tarso, en los animales evaluados, lo que puede ser utilizado como criterio de selección.

Mercury contamination in Peregrine Falcons (Falco peregrinus) in coastal Washington, 2001–2016

Mercury (Hg) is a naturally occurring widespread and persistent contaminant globally, and its organic form is highly toxic to living organisms and is known to impact humans and wildlife. Our primary goal was to use feathers to establish a contemporary baseline of total Hg contamination levels in Peregrine Falcons (Falco peregrinus) that occur on the outer coast of Washington. We document concentrations of total Hg in feathers of 151 peregrines primarily captured on beaches from 2001 to 2016. Peregrines were captured throughout the year, with breeding and natal areas of most individuals undetermined. The bulk of our samples consisted of fourth secondary (s4) feathers, but we include fourth primary and undertail covert feathers for comparison. All s4 feather samples contained detectable concentrations of total Hg (range = 0.7–69.83 µg/g), with mean concentrations in hatch-year (HY) feathers (mean = 6.05 µg/g) significantly lower than in second-year (mean = 22.55 pg/g) and after-second-year (mean = 24.48 µg/g) feathers. We captured 23 individuals more than once to track total Hg concentrations over time (up to 12 years between first and last capture), detecting an increasing trend through their third year before stabilizing in subsequent years. All individuals first captured while in HY plumage and later recaptured (n = 20) exhibited an increased concentration of total Hg in later years (mean maximum difference over time = 25.39 µg/g). Our 16-year study illustrates widespread contamination of total Hg in peregrines captured in coastal Washington, with evidence of bioaccumulation within individuals and between age classes. Encouragingly, peregrines in HY plumage sampled during the final third of our study period exhibited a significantly lower mean total Hg concentration than the first two-thirds of our study. We detected greater total Hg concentrations in coastal Washington peregrines than in nearly all known published studies involving peregrines of various subspecies in North America and Europe, although additional research is needed to establish toxic effects levels in this species.

First records of Sharp-tailed Sandpiper Calidris acuminata for Mozambique and continental Africa, and additional records of Pectoral Sandpiper C. melanotos in Mozambique, with comments on identification and patterns of occurrence

The first records of Sharp-tailed Sandpiper Calidris acuminata for Mozambique and continental Africa (1–2 adults, 4 February–16 April 2018), and additional records of Pectoral Sandpiper C. melanotos in Mozambique (1–2 birds, 20 February–31 March 2018) are reported, all at Macaneta, Maputo province. Identification features of these two species attaining breeding plumage are detailed and patterns of occurrence in Africa are discussed.

Developmental plasticity for male secondary sexual traits in a group of polyphenic tropical butterflies

Many organisms alter their investment in secondary sexual traits to optimise the fitness tradeoff between reproduction and survival. Though seasonal variation in the expression of sexual traits is evident (e.g. conspicuous breeding plumage in birds), little attention has been given to short‐lived organisms that inhabit relatively stable environments throughout their own lifetime but are exposed to strong environmental variation across generations. Some insects have evolved seasonal polyphenism to cope with intergenerational variation in environmental selection, yielding alternative phenotypes better suited for the environment in which they occur. Here we use mycalesine butterflies, which express distinct seasonal forms in response to wet‐dry seasonal environments, to explore whether seasonal polyphenism extends to secondary sexual traits. Sex pheromones, which are produced by androconial patches on the wings of males, are a key determinant of mating success in these species. Through a series of field sampling, reaction norm experiments, pheromone titre quantification, and mate competition experiments, this study reveals that the size of the androconial patch on the forewing is mediated by the temperatures experienced during development, which correspond to the ecological conditions during the alternative wet and dry seasons in the wild. Furthermore, in one of the species, Bicyclus anynana, larger forewing patches are associated with both an increase in the production of pheromone components as well as the likelihood of mating. Taken together, these findings indicate that plasticity in androconial patches may be an adaptation to seasonal fluctuations in the environment as it favours reproductive success in the conditions in which each seasonal form flies. We discuss our findings in the context of seasonal differences in the optimal tradeoff between reproduction and survival.

Virus that robs parrots of their plumage has spread around the globe

Virus that robs parrots of their plumage has spread around the globe

Dressed to impress: breeding plumage as a reliable signal of innate immunity

Animal signals involved in sexual selection are often indicators of individual quality. The assumption that sexual characters such as breeding plumage may indicate immune state has rarely been tested in free‐living migratory birds, particularly in relation to innate immunity. If sexual characters indeed reflect immune condition, then these could be used to evaluate individual quality. Melanin is a common pigment used in animal communication that mitigates the effects of oxidative stress and has positive effects on energy homeostasis, important functions during the strenuous activity of long‐distance flights. However, melanin is also immunosuppressive, and the melanised patches of breeding plumage may to some extent compromise immune responsiveness. We studied melanin‐based secondary sexual characters (SSC) in a long‐distance migratory wader, the black‐tailed godwit Limosa limosa, and found that breeding plumage features of male and female godwits are linked to components of innate immunity. Males with a larger colour extension had higher circulating levels of haptoglobin and hemolysis activity, while they also presented a lower body condition; whereas females presented a negative trend between colour and bar extension and hemolysis activity, and a positive trend for natural antibodies. The association between signal, immune state and physical condition in males suggests a cost for signal production and immune condition during prenuptial migration. Sex differences in how signals relate with immune capacity are a likely consequence of sex‐specific signalling roles and energy demands. Our results indicate that male godwit breeding plumage reflects innate immunity state, and is therefore a likely signal for females to use during mate choice as an honest indicator of male's capacity to allocate energy/resources to both expensive traits during periods of energetic constraint.

From ornament to armament or loss of function? Breeding plumage acquisition in a genetically monogamous bird.

The evolution of conspicuous male traits is thought to be driven by female mate choice or male-male competition. These two mechanisms are often viewed as distinct processes, with most studies focusing on female choice. However, both mechanisms of sexual selection can act simultaneously on the same trait (i.e., dual function) and/or interact in a synergistic or conflicting way. Dual-function traits are commonly assumed to originate through male-male competition before being used in female choice; yet, most studies focusing on such traits could not determine the direction of change, lacking phylogenetic information. We investigated the role of conspicuous male seasonal plumage in male-male competitive interactions in the purple-crowned fairy-wren Malurus coronatus, a cooperatively breeding bird. Male breeding plumage in most Malurus species is selected by female choice through extra-pair mate choice, but unlike its congeners, M.coronatus is genetically monogamous, and females do not seem to choose males based on breeding plumage acquisition. Our study shows that, within groups, subordinate males that were older, and therefore higher-ranked in the queue for breeder position inheritance, produced a more complete breeding plumage. In line with this, subordinate males that were older and/or displayed a more complete breeding plumage were more successful in competitively acquiring a breeder position. A role as a signal of competitive ability was experimentally confirmed by presenting models of males: in breeding colours, these received more aggression from resident breeder males than in nonbreeding colours, but elicited limited response from females, consistent with competitors in breeding plumage being perceived as a bigger threat to the breeder male. The role of the conspicuous breeding plumage in mediating male-male interactions might account for its presence in this genetically monogamous species. As phylogenetic reconstructions suggest a past female choice function in M.coronatus, this could represent a sexual trait that shifted functions, or a dual-function trait that lost one function. These evolutionary scenarios imply that intra- and intersexual functions of ornaments may be gained or lost independently and offer new perspectives in understanding the complex dynamics of sexual selection.

A new subspecies of the black redstart – Phoenicurus ochruros murinus subsp. nov. from the Altai-Sayan Mountainous Country and the current breeding range of the black redstart

On the basis of literature and collection materials, as well as photographs with geo-referencing from various sources, the actual breeding range of the Black Redstart Phoenicurus ochruros (Gmelin, 1774) was compiled. For the Asian part of the range, a probabilistic model is constructed for the geographic distribution of the species by the maximum entropy method, which is used to refine the range in some of its regions. Based on the collection materials of the Zoological Museum of the Moscow State University (Moscow), Zoological Institute of the Russian Academy of Sciences (St. Petersburg) and Institute of Zoology of the Republic of Kazakhstan (Almaty), a comparison of the breeding plumages of adult male Black Redstarts from the Asian part of the range was carried out. The revealed differences made it possible to describe a new subspecies from Altai, Tuva, Northern China and Western Mongolia – Phoenicurus ochruros murinus Fedorenko subsp. nov., which is distinguished from the neighboring Turkestan subspecies Ph. o. phoenicuroides by the absence of any contrast in the colour of the head, nape and back; all of which are concolourous dark grey. From Latin, the subspecies name “murinus” is translated as “mouse grey”, which characterises the colour of the upperparts of the bird. A revision of other subspecies of the Asian Black Redstart group was carried out and a map of their distribution was compiled.

Hotspots of kittiwakes Rissa tridactyla tridactyla on icebergs off southwest Greenland in autumn

The main aims of our long-term study on the quantitative at-sea distribution of the “upper trophic levels”—seabirds and marine mammals—in both polar areas are to identify and quantify the primary mechanisms influencing species distribution, as well as to detect possible temporal and spatial evolutions. During the Arctic circumpolar navigation on board icebreaking RV Polarstern in autumn (ARK-XXIII/3), 840 half-hour transect counts were devoted to the study of the at-sea distribution of seabirds and marine mammals from 12 August to 17 October 2008. High concentrations of kittiwakes Rissa tridactyla in adult summer plumage were tallied on and around a few icebergs off the southwest Greenland coast: close to 14,000 on three medium size icebergs on 15 and 16 August, and fewer on a small iceberg on 18 August, between 59°N and 70°N. These observations represented by far the majority (70%) of all kittiwakes encountered during the expedition. A possible interpretation is that these numbers, high in comparison with the local breeding population, are due to an influx of new kittiwakes in autumn, e.g. coming from more southern breeding populations in Europe. On the other hand, icebergs are known to attract actively feeding seabirds and/or marine mammals in both polar areas.

Condition Dependence of Structural Plumage Coverage in Indigo Buntings Passerina Cyanea

Nuptial plumage colouration is seemingly favoured by females of avian species with regards to sexual selection. This particular secondary sexual characteristic has been previously shown to be a condition-dependent signal of individual quality among passerines with pigment-based colouration (i.e. yellows and reds). In contrast, relationships between structural plumage colouration (i.e. blues) and aspects of both physical quality and physiological function have been understudied. Using free-living Indigo Buntings (Passerina cyanea) as a study species, we compared the percentage of blue feather coverage to body condition, innate immune responses, antioxidant capacity, stress physiology, reproductive physiology, and parasitism. We found the overall percentage of blue feathers on individual birds to be positively correlated with testosterone levels and body condition, while negatively correlated with heterophil to lymphocyte ratio. Birds with more blue coverage were also less likely to harbour blood parasites. Our results indicate male Indigo Buntings with greater moult investment have better overall body condition, lower stress, increased testosterone levels, and decreased parasitic susceptibility.

Do American Golden-Plovers (Pluvialis dominica) Avoid Wind-energy Turbines in Agricultural Fields in Indiana During Spring Migration?

ABSTRACT.— The American Golden-Plover (Pluvialis dominica), a species of conservation concern, uses large agricultural fields during its spring passage through the mid-western United States. In west-central Indiana, large numbers of golden-plovers make a stopover in corn or soybean fields that were harvested the previous fall. Stopovers last for a number of days during which the birds feed and molt into alternate plumage. In recent years, wind energy facilities have been developed in the area with hundreds of wind turbines erected in fields used by the golden-plovers. During spring 2011 and 2012, we investigated patterns of golden-plover behavior at these facilities in Benton County, Indiana at a site where large spring aggregations of plovers have been observed for many years. Our results showed only limited behavioral avoidance of the turbines, and suggested that wind-energy development in this area was not significantly impacting migrant golden-plovers. However, we caution that additional studies could...

Identification of Male Euphagus Blackbirds in Fresh Fall Plumages

Identification of Male Euphagus Blackbirds in Fresh Fall Plumages

No fitness benefits of early molt in a fairy-wren: relaxed sexual selection under genetic monogamy?

The evolution of male ornamentation has long been the focus of sexual selection studies. However, evidence is accumulating that sexually selected traits can also be lost, although the process is ill-understood. In male fairy-wrens (Malurus spp.), early molt into the seasonal breeding plumage is critical for obtaining extra-pair paternity (EPP), which reaches very high levels in these socially monogamous songbirds. A notable exception is the purple-crowned fairy-wren, Malurus coronatus, which, like its congeners, breeds cooperatively, but where EPP is very rare. Nevertheless, males develop a conspicuous seasonal breeding plumage at highly variable times. Based on 6 years of molt data collected for 137 individuals, we investigated the adaptive significance of pre-breeding molt timing as a sexual signal under (near) genetic monogamy. Molt timing varied between and within individuals with age and climate: molt was completed earlier in older males and after wetter years. Despite its potential to act as a sexual signal of male quality, fitness benefits and costs of early molt appear limited: molt timing did not correlate with 1) the likelihood of gaining a breeding position; 2) female mate preference (EPP/cuckoldry, divorce); 3) female reproductive investment (breeding timing, clutch size, number of clutches); 4) breeding performance (hatching success, fledging success, fledgling survival, annual reproductive success); and 5) male survival. However, although molt timing did not predict which subordinates would become breeders, breeders molted earlier than subordinates. The lack of EPP in this species might imply relaxed sexual selection on early molt with potential to lead to trait disappearance.

Individual identification of Black-throated Divers (Gavia arctica)

The potential to identify individual Black-throated Divers (Gavia arctica) on the basis of breeding plumage features was explored using 278 photos, including two paired birds followed during the years 2007–2015 at a specific breeding location. Observations were focused on: 1) white lines on the sides of neck, 2)mantle having rows of sharply contrasting white squares, and 3) small white spots on lesser andmedian coverts. In photos, the number ofwhite lines on the sides of neck varied from four to seven (mean = 5.0, n = 278), and the second line from the head was the highest in 92.1% of the photos. The number of “white square” rows on the mantle varied from 11 to 14 and the small white spots on coverts from 27 to 67. Identification of individual Black-throated Divers was potentially easiest if the plumage had some special patterns (19.4% of birds, n = 278). Plumage remained the same in the followed pair between years, as was also shown by the discriminant analysis, since the followed pair was correctly classified by sex but not by sides showing that sides are similar. To estimate whether it is possible to separate these two birds from other birds, a second discriminant analysis was accomplished. Thus, 125 other birds were added to analysis as a third group together with the followed pair (female andmale, nine years and n = 18 per sex). The linear discriminant analysis yielded a classification rate of 70.8% in original analysis and 69.6% based on the leave-one-out analysis (n = 161). These analyses were based on the relative height of the neck lines, their average relative height and standard deviation.When the number ofwhite spotswere added to this discriminant analysis, a correct classification rate of 77.4% in original analysis and 75.7% in the leave-one-out analysis was obtained (n = 115). These analyses suggest that the plumage can be used in identification, especially when following nesting pairs during their breeding seasons in different years. Presumed female andmaleBlack-throatedDiver could be distinguished based on the shape of the forehead.

First Study of the Turkey ( Meleagris Gallopavo ) in Cameroon: Assessing Turkey Biodiversity in the Highlands of West-Cameroon

The study was undertaken from November 2015 to January 2016. It had as a general objective to contribute to the knowledge of turkey’s biodiversity of the Highlands of West-Cameroon for their safeguard and for their genetic improvement. More specifically, it was aimed at evaluating turkeys’ morphobiometric diversity and estimating correlation coefficients between measurements and Live Weight. To achieve these goals, a sample of 236 adult turkeys whose 141 females and 95 males was randomly selected in four Divisions in the zone of study. The principal results show that the turkey’s plumage colouring in the Highlands of West-Cameroon is very varied, with a prevalence of bronzed (54.50%). Head colouring is also very variable, but the blue-red (28.94%) and pink (23.86%) are more frequent. Shanks are most often pink (36.85%), but can also be black-red (21.30%) or clear-pink (20.30%). Eyes are black-chestnut (63.13%), chestnut (16.95%) and grey-black (12.18%). In the same way, studied quantitative characters are very variable, with a sexual dimorphism in favour of the males. Thus, the average weight of the studied animals is of 6.11 ± 0.19 Kg with a variation coefficient of 49%. However, males are approximately 23% heavier (7.93 ± 0.19 Kg) than females (4.89 ± 0.25 Kg). In addition, studied body measurements are significantly (P < 0.05) higher in tom turkeys, although variable with the considered Divisions. All the correlations are positive, but correlations between Live Weight and the length of the snood (r = 0.55) and the thoracic circumference (r = 0.53) are the highest ones.

Temporal variation in the mass and plumage of four Charadriiformes species on the north-eastern coast of Brazil

Each year, thousands of Nearctic shorebirds migrate from breeding grounds in the northern hemisphere to wintering grounds in South America. At the wintering sites, in addition to moulting their flight feathers and plumage, shorebirds engage in feeding to increase body mass to gain sufficient energy for the return migration to the breeding grounds. This study aims to describe the temporal variation of body mass and plumage of the Semipalmated Plover (Charadrius semipalmatus), Spotted Sandpiper (Actitis macularius), Sanderling (Calidris alba) and Semipalmated Sandpiper (Calidris pusilla) during the wintering season on the north-eastern coast of Brazil and to evaluate the relationship between mass gain and plumage moulting. The lowest average masses for each of these species were recorded in October, November, December and January, usually when displaying non-breeding plumage. Shorebirds with intermediate and breeding plumage were frequently recorded in the migration preparation period beginning in April, with a significant increase in body mass. However, for some individuals low masses were recorded late during the wintering period and these were all found to be actively moulting. The highest values for body mass were recorded for shorebirds with breeding and intermediate plumage that were not actively moulting, nearing the end of wintering period.

A global analysis of bird plumage patterns reveals no association between habitat and camouflage.

Evidence suggests that animal patterns (motifs) function in camouflage. Irregular mottled patterns can facilitate concealment when stationary in cluttered habitats, whereas regular patterns typically prevent capture during movement in open habitats. Bird plumage patterns have predominantly converged on just four types—mottled (irregular), scales, bars and spots (regular)—and habitat could be driving convergent evolution in avian patterning. Based on sensory ecology, we therefore predict that irregular patterns would be associated with visually noisy closed habitats and that regular patterns would be associated with open habitats. Regular patterns have also been shown to function in communication for sexually competing males to stand-out and attract females, so we predict that male breeding plumage patterns evolved in both open and closed habitats. Here, taking phylogenetic relatedness into account, we investigate ecological selection for bird plumage patterns across the class Aves. We surveyed plumage patterns in 80% of all avian species worldwide. Of these, 2,756 bird species have regular and irregular plumage patterns as well as habitat information. In this subset, we tested whether adult breeding/non-breeding plumages in each sex, and juvenile plumages, were associated with the habitat types found within the species’ geographical distributions. We found no evidence for an association between habitat and plumage patterns across the world’s birds and little phylogenetic signal. We also found that species with regular and irregular plumage patterns were distributed randomly across the world’s eco-regions without being affected by habitat type. These results indicate that at the global spatial and taxonomic scale, habitat does not predict convergent evolution in bird plumage patterns, contrary to the camouflage hypothesis.

Molts and Plumages in the Long-tailed and Other Jaegers: An “Alternate” Explanation for Nonbreeding Plumages?

Molts and Plumages in the Long-tailed and Other Jaegers: An “Alternate” Explanation for Nonbreeding Plumages?

Parental care and external sexual characters in the Warbling Doradito (Pseudocolopteryx flaviventris)

Fil: Cardoni, Daniel Augusto. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina