A reference genome assembly of the declining tricolored blackbird, Agelaius tricolor.

The tricolored blackbird, Agelaius tricolor, is a gregarious species that forms enormous breeding and foraging colonies in wetland and agricultural habitats, primarily in California, USA. Once extremely abundant, species numbers have declined dramatically in the past century, largely due to losses of breeding and foraging habitats. Tricolored blackbirds are currently listed as Endangered by the IUCN, and Threatened under the California Endangered Species Act. Increased genetic information is needed to detail the evolutionary consequences of a species-wide bottleneck and inform conservation management. Here, we present a contiguous tricolored blackbird reference genome, assembled with PacBio HiFi long reads and Dovetail Omni-C data to generate a scaffold-level assembly containing multiple chromosome-length scaffolds. This genome adds a valuable resource for important evolutionary and conservation research on tricolored blackbirds and related species.

Comparing perineuronal nets and parvalbumin development between blackbird species with differences in early developmental song exposure.

Brood parasitic songbirds are a natural system in which developing birds are isolated from species-typical song and therefore present a unique opportunity to compare neural plasticity in song learners raised with and without conspecific tutors. We compared perineuronal nets (PNN) and parvalbumin (PV) in song control nuclei in juveniles and adults of two closely related icterid species (i.e. blackbirds): brown-headed cowbirds (Molothrus ater; brood parasite) and red-winged blackbirds (Agelaius phoeniceus; non-parasite). The number of PV cells per nucleus was significantly higher in adults compared with juveniles in the nucleus HVC and the robust nucleus of the arcopallium (RA), whereas no significant species difference appeared in any region of interest. The number of PNN per nuclei was significantly higher in adults compared with juveniles in HVC, RA and Area X, but only RA exhibited a significant difference between species. PV cells surrounded by PNN (PV+PNN) also exhibited age-related differences in HVC, RA and Area X, but RA was the only region in which PV+PNN exhibited significant species differences. Furthermore, a significant interaction existed in RA between age and species with respect to PNN and PV+PNN, revealing RA as a region displaying differing plasticity patterns across age and species. Additional comparisons of PNN and PV between adult male and female cowbirds revealed that males have greater numbers of all three measures in RA compared with females. Species-, sex- and age-related differences in RA suggest that species differences in neural plasticity are related to differences in song production rather than sensitivity to song learning, despite a stark contrast in early exposure to conspecific male tutors.

A comprehensive species-level molecular phylogeny of the New World blackbirds (Icteridae).

The New World blackbirds (Icteridae) are among the best known songbirds, serving as a model clade in comparative studies of morphological, ecological, and behavioral trait evolution. Despite wide interest in the group, as yet no analysis of blackbird relationships has achieved comprehensive species-level sampling or found robust support for most intergeneric relationships. Using mitochondrial gene sequences from all ∼108 currently recognized species and six additional distinct lineages, together with strategic sampling of four nuclear loci and whole mitochondrial genomes, we were able to resolve most relationships with high confidence. Our phylogeny is consistent with the strongly-supported results of past studies, but it also contains many novel inferences of relationship, including unexpected placement of some newly-sampled taxa, resolution of relationships among major clades within Icteridae, and resolution of genus-level relationships within the largest of those clades, the grackles and allies. We suggest taxonomic revisions based on our results, including restoration of Cacicus melanicterus to the monotypic Cassiculus, merging the monotypic Ocyalus and Clypicterus into Cacicus, restoration of Dives atroviolaceus to the monotypic Ptiloxena, and naming Curaeus forbesi to a new genus, Anumara. Our hypothesis of blackbird phylogeny provides a foundation for ongoing and future evolutionary analyses of the group.

Blue nests: The use of plastics in the nests of the crested oropendola (Psarocolius decumanus) on the Brazilian Amazon coast.

Birds have been impacted by plastic pollution via entanglement, accidental ingestion, and exposure to chemical contaminants. However, plastics were also observed as a nesting material for several species. For the first time, we describe the occurrence and composition of plastics in 36 nests of the crested oropendola (Psarocolius decumanus) in three different sites on the Amazon coast. Plastics were present in 67 % of abandoned, fallen nests. At the mangrove site, all nests contained plastics, while at the grassy clearing and the fishermen's village, plastics were present at 35.3 and 90 % of the nests, respectively. Blue fibers and ropes were the main plastics observed, probably derived from discarded fishing gear. Of 79 analyzed fibers, 97.5 % were composed of Polyethylene, and 83.5 % contained Cobalt Phthalocyanine as an additive. Our results showed a widespread use of plastics by P. decumanus, which may increase the exposure of both juveniles and adults to potential contaminants.

Amblyomma ticks consumed by a giant cowbird, Molothrus oryzivorus.

The removal of ectoparasites is a common behavior found across animal taxa and is a determinant to avoid the negative effects of parasites' presence. Eventually, the elimination of ectoparasites is associated with mutualistic interactions. Cleaner birds remove ectoparasites, providing benefits to its mutualistic host by reducing parasite burden while they obtain a protein food source. Here we report some evidence that giant cowbirds (Molothrus oryzivorus) may have an important role as a cleaner bird. We found 74 adult ticks inside the ventriculus of one male giant cowbird. The ticks belonged to three different species: Amblyomma dubitatum, A. sculptum and A. triste. We found that the sex-ratio of the consumed adult ticks was not different from 1:1. Although additional data are necessary, the large number of ticks found suggests that the giant cowbird may have developed a mutualistic association with large, social mammals such as capybaras (Hydrochoerus hydrochaeris), since this animal is an important host species for the three tick species found in the present study.

Brueelia (Phthiraptera: Ischnocera: Philopteridae) of North American Nine-Primaried Oscines (Aves: Passeriformes: Passerida) with Descriptions of Nine New Species.

Nine new species of chewing lice in the genus Brueelia Kéler, 1936 , are described from North American hosts. They are Brueelia thorini n. sp. from Haemorhous mexicanus frontalis (Say, 1822) and Haemorhous mexicanus potosinus Griscom, 1928; Brueelia straseviciusi n. sp. from Haemorhous purpureus (Gmelin, 1789); Brueelia mattsonae n. sp. from Coccothraustes vespertinus brooksi (Grinnell, 1917); Brueelia novemstriata n. sp. from Icterus wagleri wagleri Sclater, 1857, and I. parisorum Bonaparte, 1838; Brueelia benkmani n. sp. from Pheucticus melanocephalus (Swainson, 1827); Brueelia arizonae n. sp. from Passerina caerulea (Linnaeus, 1758); Brueelia hellstromi n. sp. from Piranga ludoviciana (Wilson, 1811); Brueelia dolorosa n. sp. from Spinus pinus pinus (Wilson, 1810); and Brueelia melancholica n. sp. from Spinus tristis (Linnaeus, 1758). Brueelia limbata ( Burmeister, 1838 ) is redescribed and illustrated from North American material. A key for these North American species is provided.

The economic impacts of blackbird (Icteridae) damage to sunflower in the USA.

BACKGROUND: Blackbird (Icteridae) damage to ripening sunflower (Helianthus annuus L.) has been a persistent economic issue in the USA for the last five decades. To quantify losses, we surveyed blackbird damage from 2001 to 2013 (excluding 2004) to physiologically mature sunflower in eight states: North Dakota, South Dakota, Texas, Nebraska, Minnesota, Colorado, Kansas, and Vermont. RESULTS: We pooled data gathered during the most recent 5 years (2009 to 2013) of the survey and found losses averaged $US2.5 million and $US11.3 million for confectionery and oilseed hybrids, respectively. Three states, North Dakota, South Dakota, and Nebraska, had sufficient acreage and bird damage to warrant economic analyses using a regional economic model. The average annual total (direct plus indirect) economic impact of bird damage to sunflower production for North Dakota, South Dakota, and Nebraska was $US18.7 million, $US7.3 million, and $US2.6 million, respectively. CONCLUSION: This study provides a better understanding of the broader economic implications of bird damage to sunflower by estimating the macroeconomic impacts of lost sunflower production in the region. Additionally, the findings of this study may be used to inform decisions regarding bird management policy by providing policymakers with information to determine the downstream value of bird management and the possible benefits of improved methods that further mitigate losses. © 2019 Society of Chemical Industry.

Anidación de Psarocolius decumanus (Aves: Icteridae), en localidades del departamento de Sucre, Colombia / Nesting of Psarocolius decumanus (Aves: Icteridae), in localities of the department of sucre, colombia

Introducción. Psarocolius decumanus es una especie relativamente abundante en el departamento de Sucre, Colombia, pero no se cuenta con información suficiente acerca de su reproducción. Materiales y Métodos. A través de observación directa y recorridos libres se determinó el número de nidos por colonias, los árboles donde son construidos, materiales utilizados, la altura a que se encontraban y se obtuvo información sobre la duración del periodo reproductivo y comportamiento parental, durante varios meses de muestreo (febrero a octubre), en diferentes localidades de la región. Resultados. Los nidos se construyen en colonias de hasta diez nidos y son defendidos por individuos de ambos sexos, aunque en su construcción, alimentación de los pichones y protección de cada nido solo intervienen las hembras. La ubicación de los nidos en árboles altos, aislados, en zonas abiertas o semiabiertas, en el extremo de ramas finas, parece constituir una estrategia anti-depredación. La construcción comienza en febrero, la puesta de los huevos es a mediados de marzo, la incubación dura 18 días aproximadamente y los pichones independientes fueron observados 33 días después de la eclosión de los huevos, a finales de mayo y principios de junio. Este proceso debe extenderse varios meses, ya que se observó construcción de nidos hasta junio. Conclusión. Casi todas las características de la anidación en esta especie están enfocadas, sobre todo, a la protección contra la depredación y el parasitismo.

Introduction. Psarocolius decumanus is a relatively abundant species in the department of Sucre, Colombia and there is not enough information about its reproduction. Materials and methods. Through direct observation and free routes, the number of nests per colonies was determined, also the trees where they were built, the materials used, the height they were at, and information was obtained on the duration of the reproductive period and parental behavior, for several months of sampling (February to October) in different localities of the region. Results. The nests are built in colonies of up to 10 nests and are defended by individuals of both sexes, although in its construction, feeding the pigeons and protection of each single nest, involved only females. The location of nests in tall, isolated trees, in open or semi-open areas, at the end of thin branches, seems to be an anti-predation strategy. The construction begins in February, the eggs are laid in mid-March, the incubation lasts approximately eighteen days and the independent chicks were observed thirty-three days after the hatching of the eggs, at the end of May and the beginning of June. This process should extend several months, since construction of nests were observed until June. Conclusion. Almost all nesting characteristics in this species are focused, above all, on protection against predation and parasitism.

How far will a behaviourally flexible invasive bird go to innovate?

Behavioural flexibility is considered a key factor in the ability to adapt to changing environments. A traditional way of characterizing behavioural flexibility is to determine whether individuals invent solutions to novel problems, termed innovativeness. Great-tailed grackles are behaviourally flexible in that they can change their preferences when a task changes using existing behaviours; however, it is unknown how far they will go to invent solutions to novel problems. To begin to answer this question, I gave grackles two novel tests that a variety of other species can perform: stick tool use and string pulling. No grackle used a stick to access out-of-reach food, even after seeing a human demonstrate the solution. No grackle spontaneously pulled a vertically oriented string, but one did pull a horizontally oriented string twice. Additionally, a third novel test was previously conducted on these individuals and it was found that no grackle spontaneously dropped stones down a platform apparatus to release food, but six out of eight did become proficient after training. These results support the idea that behavioural flexibility is a multi-faceted trait because grackles are flexible, but not particularly innovative. This contradicts the idea that behavioural flexibility and innovativeness are interchangeable terms.

Behavioral flexibility and problem solving in an invasive bird.

Behavioral flexibility is considered an important trait for adapting to environmental change, but it is unclear what it is, how it works, and whether it is a problem solving ability. I investigated behavioral flexibility and problem solving experimentally in great-tailed grackles, an invasive bird species and thus a likely candidate for possessing behavioral flexibility. Grackles demonstrated behavioral flexibility in two contexts, the Aesop's Fable paradigm and a color association test. Contrary to predictions, behavioral flexibility did not correlate across contexts. Four out of 6 grackles exhibited efficient problem solving abilities, but problem solving efficiency did not appear to be directly linked with behavioral flexibility. Problem solving speed also did not significantly correlate with reversal learning scores, indicating that faster learners were not the most flexible. These results reveal how little we know about behavioral flexibility, and provide an immense opportunity for future research to explore how individuals and species can use behavior to react to changing environments.

Parasites of the Shiny Cowbird, Molothrus bonariensis, and the Austral Blackbird, Curaeus curaeus, (Passeriformes: Icteridae) in Chile / Parasitas do chupim Molothrus bonariensis e do pássaro-preto-austral Curaeus curaeus (Passeriformes: Icteridae) no Chile

Abstract Comparative studies of parasites in sympatric bird species have been generally scarce. Parasitic infection/transmission can be spread in a number of ways that suggests possible direct and indirect, horizontal transmission between avian hosts. In order to determine whether two sympatric icterids from Central and Southern Chile share their parasite fauna (ecto- and endoparasites), we examined parasites of 27 Shiny Cowbirds, Molothrus bonariensis, and 28 Austral Blackbirds, Curaeus curaeus, including individuals captured in the wild and carcasses. We found that Shiny Cowbirds were infected with the chewing lice Brueelia bonariensis, Philopterus sp. 1, the feather mites Amerodectes molothrus, Proctophyllodes spp. (species 1 and 2), and the helminths Mediorhynchus papillosus, Plagiorhynchus sp., Dispharynx nasuta and Tetrameres paucispina, while Austral Blackbirds had the chewing lice Myrsidea sp., Philopterus sp. 2, the feather mites Proctophyllodes sp. 3, Amerodectes sp., and three helminths: Anonchotaenia sp., Capillaria sp. and M. papillosus. The flea Dasypsyllus (Neornipsyllus) cteniopus was found only on the Austral Blackbird. The only parasite species shared by both icterids was the acanthocephalan M. papillosus, possibly due to their feeding on the same intermediate insect hosts. With the exception of B. bonariensis and Philopterus sp. 1 found on the Shiny Cowbird, all species reported in this study represent new parasite-host associations and new records of parasite diversity in Chile.

Resumo Estudos comparativos de parasitas em espécies de aves simpátricas são escassos. A infecção/transmissão de parasitas pode acontecer de diversas maneiras, incluindo possível transmissão direta, indireta ou horizontal entre as aves hospedeiras. Com o objetivo de determinar se dois icterídeos simpátricos do centro e sul do Chile compartilham a sua fauna parasitária (ecto- e endoparasitas), foram examinados os parasitas de 27 chupins Molothrus bonariensis e 28 pássaros-pretos-austral Curaeus curaeus, incluindo indivíduos capturados com rede de neblina e em carcaças. Nos chupins analisados, foram encontrados os piolhos de penas Brueelia bonariensis, Philopterus sp. 1, os ácaros Amerodectes molothrus, Proctophyllodes spp. (espécie 1 e 2), e os helmintos Mediorhynchus papillosus, Plagiorhynchus sp., Dispharynx nasuta e Tetrameres paucispina. Em contraste, os pássaros-pretos-austral estavam infectados com os piolhos Myrsidea sp., Philopterus sp. 2, os ácaros Proctophyllodes sp. 3, Amerodectes sp., e os helmintos Anonchotaenia sp., Capillaria sp. e M. papillosus. Adicionalmente, um espécime de pássaro-preto-austral estava parasitado pela pulga Dasypsyllus (Neornipsyllus) cteniopus. A única espécie de parasita que foi encontrada nas duas espécies de aves foi o acantocéfalo M. papillosus, possivelmente devido ao fato de que ambas as aves se alimentam dos insetos que são os hospedeiros intermediários deste parasita. Exceto os registros de B. bonariensis e Philopterus sp. 1 encontrados no chupim, todas as espécies reportadas neste estudo correspondem à novas associações de parasita/hospedeiro e novos registros para a diversidade parasitológica do Chile.

Differentiating the evolution of female song and male-female duets in the New World blackbirds: can tropical natural history traits explain duet evolution?

Female bird song and combined vocal duets of mated pairs are both frequently associated with tropical, monogamous, sedentary natural histories. Little is known, however, about what selects for duetting behavior versus female song. Female song likely preceded duet evolution and could drive apparent relationships between duets and these natural histories. We compared the evolution of female song and male-female duets in the New World blackbirds (Icteridae) by investigating patterns of gains and losses of both traits and their relationships with breeding latitude, mating system, nesting pattern, and migratory behavior. We found that duets evolved only in lineages in which female song was likely ancestral. Both female song and duets were correlated with tropical breeding, social monogamy, territorial nesting, and sedentary behavior when all taxa were included; however, correlations between duets and these natural history traits disappeared when comparisons were limited to taxa with female song. Also, likelihood values supported stronger relationships between the natural history traits and female song than between these traits and duets. Our results suggest that the natural histories thought to favor the evolution of duetting may in fact be associated with female song and that additional selection pressures are responsible for the evolution of duets.

Courtship Disruptions and Male Mating Strategies: Examples from Female-Defense Mating Systems.

Males frequently interrupt the copulation attempts of other males, and these courtship disruptions may limit the extent to which a few males are able to monopolize mating access to females. Males actively defend sexually receptive females in many species in which females form dense aggregations during the breeding season. Across and within such species there is considerable variation in the mating tactics adopted by males, with males in some cases defending groups of females and in other cases sequentially consorting with individual females. Colonial blackbirds have been central to studying this mating system, and we develop a conceptual model for how courtship disruption may account for variation in male mating tactics in this group. Our model assumes that the frequency of disruptions increases with greater colony size. As a consequence, successful copulations are less likely to occur at large colonies than at small colonies, and males are expected to switch from defending multiple females at the colony to consorting individual females away from it. Results from two species of blackbird support the basic assumptions of this model. In one species, the Montezuma oropendola, disruptions occur rarely and males defend groups of females, whereas in the other species, the yellow-rumped cacique, disruptions are frequent and males defend single females. Moreover, consistent with a key prediction, within each species, males associated with small colonies remain at the colony and defend groups of females, whereas males spend little time defending groups of females at large colonies and rarely attempt copulations there. This model has the potential to explain variation in male mating strategies and female monopolization for other taxa in which females form breeding aggregations.

Effects of superabundant food on breeding success and behavior of the red-winged blackbird.

The effects of food on breeding success and behavior of the red-winged blackbird (Icteridae: Agelaius phoeniceus) were investigated during 3 successive breeding seasons. In the second season, a 4-week pulse of abundant food in the form of a periodical cicada emergence (Homoptera: Cicadidae: Magicicada spp.) occurred in the forest adjacent to the marsh where the birds were breeding.During the cicada period, the bird population showed: 1) an increase in foraging trips to the forest and a decrease in trips per h, 2) increased biomass of nestlings, 3) increased nestling survival caused by decreased starvation, 4) increased fledging success, and 5) bimodal weight distributions of older nestlings (reflective of the sexual dimorphism in this species). These data suggest the temporary removal of food limitations on the breeding population when the pulse of food was available.

Brazilian cleaner birds: update and brief reappraisal / Aves limpadoras Brasileiras: atualização e breve reavaliação

Some bird species feed on external parasites, such as ticks and flies, on the body of mammals (hosts or clients). So called cleaner birds that occur in Brazil were reviewed recently, but gathering of significant new data indicates the need for an update and a brief reappraisal of such association. New records raise the number of known clients for some cleaning birds. The Southern Caracara (Caracara plancus) picks ticks on cattle, and the Black Caracara (Daptrius ater) picks ticks on capybaras. The Wattled Jacana (Jacana jacana) picks ticks, horseflies, arthropods and organic debris on capybaras, and tick-picking on capybaras by the Shiny Cowbird (Molothrus bonariensis) is substantiated by photographs. The Cattle Tyrant (Machetornis rixosa) deftly catches horseflies on capybaras, and these latter clients are recorded posing for the Giant Cowbird (Molothrus oryzivorus), which also pick parasites from the marsh deer. The Cattle Egret (Bubulcus ibis) definitely picks ticks directly on cattle. With the new records, some poorly documented or controversial issues in the literature are here confirmed, a hypothesis is validated, and a suggestion is invalidated.

Algumas espécies de aves alimentam-se de parasitas externos, como carrapatos e moscas, sobre o corpo de mamíferos (hospedeiros ou clientes). As assim denominadas aves limpadoras que ocorrem no Brasil foram recentemente revistas, porém o acúmulo de novos e importantes dados indica a necessidade de atualização e breve reavaliação deste tipo de associação. Novos registros elevam o número de clientes conhecidos para algumas espécies de aves limpadoras. O caracará (Caracara plancus) cata carrapatos em gado vacum, e o gavião-de-anta (Daptrius ater) apanha carrapatos em capivaras. A jaçanã (Jacana jacana) apanha carrapatos, mutucas, artrópodes e partículas orgânicas em capivaras, e a retirada de carrapatos em capivaras pelo vira-bosta (Molothrus bonariensis) é aqui evidenciada por fotografias. O suiriri-cavaleiro (Machetornis rixosa) caça destramente mutucas em capivaras, e estes últimos clientes são aqui registrados posando para a iraúna-grande (Molothrus oryzivorus), que também cata parasitas do cervo-do-pantanal. A garça-vaqueira (Bubulcus ibis) de fato apanha carrapatos diretamente no gado. Com os novos registros, alguns assuntos pouco documentados ou controversos na literatura são aqui confirmados, uma hipótese é validada, e uma sugestão é invalidada.

EVOLUTION, PHYLOGENY, SEXUAL DIMORPHISM AND MATING SYSTEM IN THE GRACKLES (QUISCALUS SPP.: ICTERINAE).

According to theory, two consequences of sexual selection are sexual dimorphism in size and secondary sexual characteristics, due to either intra- or intersexual selection. In this paper I suggest three criteria for the test of an evolutionary hypothesis involving quantitative morphological characters. First, the postulated change must be shown to have occurred in evolutionary time. Second, this change must be positively correlated with a change in the proposed selective agent. Third, given two taxa with different degrees of sexual size dimorphism and different mating system, the possible influence of drift must be rejected. If the hypothesis is not rejected by these three criteria, then we still have no proof of causality, but we can at least be more confident about its plausibility. This is applied to the particular hypothesis that sexual dimorphism in the Boat-tailed and Great-tailed grackles (Quiscalus spp; Icterinae; Aves) is caused by the highly polygynous mating system in these species. In relation to an outgroup, both species have increased disproportionately in male tarsus and tail size, creating an increased sexual dimorphism. This has cooccurred with the evolution of their particular mating system. However, the variance among species in male tarsus size can be accounted for by drift, and need not be a result of selection for increased size. In contrast, the variance among species in male tail size was much larger than expected under a null model of drift, indicating directional selection for long tails. The variance in female tail size was not larger than expected by drift, whereas the variance in female tarsus size was in fact lower than expected by drift, indicating stabilizing selection. The data are consistent with the hypothesis with regard to tail size, but not with regard to body size.