Passerine Research Articles

Host-feeding preferences of Culex pipiens and its potential significance for flavivirus transmission in the Camargue, France.

The spread of the West Nile (WNV) and Usutu (USUV) flaviviruses in Europe in recent decades highlights the urgent need to understand the transmission networks of these pathogens as a basis for effective decision-making. These viruses are part of a complex disease cycle that involves birds as principal hosts and humans and horses as dead-end hosts. Our study aims to uncover the intricate relationships between the main mosquito vector of these viruses, Culex pipiensL. (Diptera: Culicidae) and its feeding preferences based on the forage ratio among several host species, primarily birds in a land-use gradient. We estimated the bird host potential to act as a host for flavivirus, the reservoir capacity index, based on forage ratios and potential host competence based on molecular prevalence. We sampled mosquitoes and, at the same time, conducted bird censuses in the Camargue region in southern France, where co-circulation of these viruses has been reported. Several localities were sampled along a land-use gradient in peri-urban, agricultural and natural areas from May to November 2021. We identified 55 vertebrate species in 110 engorged Cx. pipiens by PCR amplification and sequencing of mitochondrial 12S and 16S Ribosomal DNA genes. Culex pipiens feeds primarily on 51 bird species and secondarily on two mammals, one amphibian and one reptile. Based on forage ratios, we found a preference of Cx. pipiens in the Camargue for the order Passeriformes and, more specifically, for Columba livia domestica L. (Columbiformes: Columbidae) in agricultural areas, and for Passer domesticus/montanus L. (Passeriformes: Passeridae), in agricultural and peri-urban areas. The natural habitats had significantly higher forage ratio values than agricultural and peri-urban areas. We suggest that certain key species, such as Passer sp., Columba livia and Turdus sp., might be potentially considered locally relevant hosts for transmission in this area, as they are important for mosquito feeding and also potentially important hosts for flavivirus amplification. These data will be beneficial in understanding host-vector interactions and the relationships between bird communities, mosquito feeding preferences and emerging mosquito-borne diseases.

Highly accurate Batesian mimicry of wasps dates back to the Early Oligocene and was driven by non-passerine birds.

Highly accurate Batesian mimicry of wasps dates back to the Early Oligocene and was driven by non-passerine birds.

Mycoplasma spp. in Passeriformes in Germany.

Little is known about the significance of mycoplasmas in different free-ranging bird species. One hypothesis is that the prevalence of mycoplasmas and the influence of vocalization on reproduction are evolutionarily linked. To add another piece of information toward proving or disproving this hypothesis and obtain more information about the clinical relevance of mycoplasmas, choanal swabs from different passerine species presented to a veterinary clinic were examined for mycoplasmas using culture and Mycoplasma genus-specific PCR. When mycoplasmas were detected, the species was identified by sequencing the partial 16S rRNA and 16S-23S rRNA intergenic spacer region. In total, 221 passerines from 34 species and 17 families were sampled. Mycoplasmas were detected in 12% of the Passeriformes and mostly in four families: Sturnidae, Muscicapidae, Turdidae, and Hirundinidae. The most commonly detected Mycoplasma sp. was Mycoplasma sturni; this did not seem to be an obligate pathogen. Additionally, Mycoplasma columborale, Mycoplasma moatsii, and two unidentified Mycoplasma spp. were detected. The results indicate that in some passerine families, mycoplasmas occur with an intermediate prevalence. The rare occurrence of mycoplasmas in many passerine bird species seems to be in accordance with the hypothesis of an evolutionary link between mycoplasma prevalence and the influence of vocalization on reproduction, but the findings of our study could not prove or disprove this hypothesis. Further studies of mycoplasma prevalence in free-ranging passerine populations are needed.

High-elevation birds grow more slowly but to heavier weights than low-elevation birds.

Documenting how growthstrategies diverge among populations or species occupying different geographical locations can contribute to understanding life-history evolution. However, the existing literature on the geography of growth focuses on latitudinal gradients, leaving the growth-elevation relationship enigmatic. The knowledge gap limits our ability to capture a full picture of growth evolution at macroecological scales because organisms typically experience different selective pressures across these two geographical gradients. We filled this gap using data from 163 populations of 111 passerine species breeding in mainland China over an elevational span of 8-4500 m. Phylogenetic comparative analyses revealed that controlling for potentially confounding variables, the growth rate of nestling body mass decreased and the nestling period became longer as elevation increased. Also, high-elevation nestlings fledged at a heavier body mass relative to the adult than their low-elevation congeners. The observed growth patterns, coupled with fewer, larger eggs and prolonged parental care as demonstrated by earlier studies, suggest that avian life histories have slowed down toward high elevations. The life-history strategy, which stands in contrast to the fast pace of life toward high latitudes, is likely a response to increasingly stressful conditions with elevation, especially the limited availability of food and oxygen.

The Eurasian Harvest Mouse Micromys minutus feeding on nestlings of the Eurasian Reed Warbler Acrocephalus scirpaceus

The Eurasian Harvest Mouse is the smallest rodent of Eurasia, inhabiting mostly areas with tall grasses, including reedbeds. Its food consists of mostly various plants (chiefly seeds, fruit and leaves), but also beetles and other invertebrates. Previous studies revealed the presence of mammal hair in faecal pellets of the species, but it remained unclear whether the species was a predator of other rodents or their scavenger. Here we describe the case (recording) of a Harvest Mouse consuming two 8-day-old nestlings of the Reed Warbler, a passerine bird. The Mouse foraged on soft parts of the trunk and belly, while hard parts (heads, legs and wings) remained in the nest. This observation shows that Harvest Mice may attack vertebrates. Our study provides also the first record of birds as food of the species.

Associations between human non‐motorised recreational activity on nest box occupation, exploratory behaviour and breeding success in a passerine bird

Associations between human non‐motorised recreational activity on nest box occupation, exploratory behaviour and breeding success in a passerine bird

The unexpected loss of the 'hunger hormone' ghrelin in true passerines: a game changer in migration physiology.

Migratory birds must accumulate large amounts of fat prior to migration to sustain long flights. In passerines, the small body size limits the amount of energy stores that can be transported, and therefore birds undergo cycles of extreme fattening and rapid exhaustion of reserves. Research on these physiological adaptations was rattled by the discovery that birds have lost the main vertebrate regulator of fat deposition, leptin. Recent studies have thus focused on ghrelin, known as 'hunger hormone', a peptide secreted by the gastrointestinal tract to regulate, e.g. food intake and body mass in vertebrates. Studies on domestic species showed that, in birds, ghrelin has effects opposite to those described in mammals such as inhibiting instead of promoting food intake. Furthermore, recent studies have shown that ghrelin administration influences migratory behaviour in passerine birds. Using comparative genomics and immunoaffinity chromatography, we show that ghrelin has been lost in Eupasseres after the basic split from Acanthisitti about 50 Ma. We found that the ghrelin receptor is still conserved in passerines. The maintenance of a functional receptor system suggests that in Eupasserines, another ligand has replaced ghrelin, perhaps to bypass the feedback system that would hinder the large pre-migratory accumulation of subcutaneous fat.

Anthropogenic materials in the nests of Passerine birds: does the environment matter?

Anthropogenic materials in the nests of Passerine birds: does the environment matter?

Host-feeding behavior of mosquitoes (Diptera: Culicidae) in North Dakota, 2003 to 2006.

Mosquitoes are abundant near temporary, semipermanent, and permanent water in North Dakota and are associated with human and veterinary diseases. Little is known about the feeding habits of mosquitoes as related to the transmission of arboviruses. We report on the identification of vertebrate hosts of 9 species of mosquitoes collected in 2003 to 2006. Blood meals of 1,223 from 9 mosquito species were identified to vertebrate species by PCR assays using the mitochondrial cytochrome b gene. Aedes dorsalis (Diptera: Culicidae) and Culiseta inornata fed only on mammals, and Aedes vexans fed almost exclusively on mammals. Aedes trivittatus fed significantly more on mammals than on birds. Culex tarsalis acquired blood meals from the most diverse group of vertebrates, frequently fed on American Robins, and did not exhibit a seasonal shift of feeding on birds to mammals. The extensive feeding of Cx. tarsalis on passerine birds and the isolation of West Nile virus (WNV) from 2 specimens that had fed on passerines supports their role in horizontal transmission of WNV. This species also transmits western equine encephalitis virus. Host feeding by Ae. trivittatus, Ae. vexans, Cs. inornata, and Ae. dorsalis in relation to their possible importance in transmission of trivittatus virus, Cache Valley virus, Jamestown Canyon virus, Potosi virus, or snowshoe hare virus is presented. The identification of host feeding behavior pattern of specific species of mosquitoes enhances our understanding of the enzootic and epizootic nature of 7 viruses in North Dakota.

Expanding protected area coverage for migratory birds could improve long-term population trends

Populations of many migratory taxa have been declining over recent decades. Although protected areas are a cornerstone for conservation, their role in protecting migratory species can be incomplete due to the dynamic distributions of these species. Here, we use a pan-European citizen science bird occurrence dataset (EurobirdPortal) with Spatiotemporal Exploratory Modelling to assess how the weekly distributions of 30 passerine and near passerine species overlap with protected areas in Europe and compare this to range adjusted policy protection targets. Thirteen of our 30 species were inadequately covered by protected areas for some, or all, of the European part of their annual cycle under a target based on the 2020 Convention on Biodiversity framework and none were adequately covered under a target based on the 2030 Convention on Biodiversity framework. Species associated with farmland had the lowest percentage of their weekly distribution protected. The percentage of a species’ distribution within protected areas was positively correlated with its long-term population trend, even after accounting for confounding factors, suggesting a positive influence of protected areas on long-term trends. This emphasises the positive contribution that an informed expansion of the European protected area system could play for the future conservation of migratory land birds.

Characterization of bird communities in four riparian habitats along the Sinaloa River, northwest Mexico

ABSTRACT This study characterizes the species diversity, richness, composition, and structure of avifauna in four riparian habitats (Bamoa, La Criba, Malecon, and Estero) along the Sinaloa River in northwest Mexico. The research was conducted from March to November 2024, employing the strip transect method and fixed-radius point count method for the bird survey. Data were analysed using the Shannon-Wiener, Simpson, and Margalef indices, relative abundance index, and Jaccard similarity coefficient. A total of 146 species were recorded across 19 orders and 47 families, with the order Passeriformes being the most represented. The Estero habitat exhibited the highest diversity and species richness, while Bamoa and La Criba showed the greatest similarity. The most abundant species were generalists adapted to human-altered environments (Zenaida asiatica, Tachycineta albilinea, Quiscalus mexicanus, and Passer domesticus). This study provides essential data for future conservation strategies in riparian ecosystems.

Spatio-Temporal Characterization of Nest-Niche in Passerine Birds Co-Occurring in Olive Agro-Ecosystems: Partitioning of Nesting Sites, Breeding Chronology, and Productivity

Many birds regard partitioning feeding and breeding resources as a strategy to escape competition and co-occurring breeding species. During the breeding season, breeding requirements are essential, yet the patterns and drivers of segregation between and within populations are poorly understood. We monitored the habitat use and chronology of the four co-occurring passerines Eurasian Blackbird, European Greenfinch, Common Chaffinch, and European Serin to examine levels of habitat partitioning and success rates during the breeding season. We recorded nesting sites, nest supports, nest placement, breeding chronology, and productivity in four olive orchards in Fez, central Morocco, from March to August 2018–2019. Our results showed substantial spatial segregation in nesting sites, nest supports, and tree vertical placements. Breeding birds showed significant temporal segregation during the nesting, laying, and hatching phases. These findings suggest distinct spatial and temporal differences in habitat selection among co-occurring passerines, which are suggested to increase avoidance of intra and interspecific competition for resources. Breeding success was very high in European Serin and Eurasian Blackbird. Failure factors were recorded: eggs of European Serin were threatened principally by desertion, abortion, and destruction, and eggs of European Greenfinch were impacted by poaching by children. Our findings provide the first data on the spatial and temporal partitioning of breeding resources among passerines species in Northwest African and probably Mediterranean agroecosystems.

Observational and experimental evidence that rapid mass loss is consistent with the flight efficiency hypothesis and not caused by reproductive effort in three passerine species

Abstract Breeding birds often lose mass abruptly around the time that their eggs hatch, but the reasons why and the demographic significance of mass loss are contentious. Energy expenditure during offspring provisioning is one long‐standing explanation that fits with life‐history theory (energetic cost hypothesis). Mass loss may also reflect time constraints that limit foraging and self‐maintenance while warming (i.e. brooding) young (time constraint hypothesis). Alternatively, mass loss may be an adaptive strategy to provide benefits through decreased energetic flight costs while foraging and provisioning young (flight efficiency hypothesis). To test these hypotheses, we measured mass loss across the nesting cycle for three passerine species using an automated weighing system and quantified reproductive effort by filming nests. We also experimentally manipulated reproductive effort using a nest heating experiment to test effects on mass loss. Counter to the energetic cost hypothesis, female mass loss did not match changing parental provisioning effort across the reproductive cycle; mass loss in all three species started about 5 days before eggs hatched and finished well before nestling provisioning effort was greatest. The nest heating experiment reduced female and male provisioning rates but did not influence mass loss in either sex, also rejecting the energetic cost hypothesis. Counter to the time constraint hypothesis, more time spent brooding was associated with less mass loss. Path analysis supported the flight efficiency hypothesis for females, where mass loss was not related to energetic costs or time constraints and was positively associated with fledging more and heavier young, as well as a greater proportion of young. Mass loss also did not influence the chance of double‐brooding or survival to the next breeding season. Males lost mass steadily over the nesting cycle, but our results did not strongly support one hypothesis. Ultimately, results supported mass loss providing adaptive benefits for females, while rejecting reproductive cost hypotheses often expected under life‐history theory. Read the free Plain Language Summary for this article on the Journal blog.

Impacts of an organophosphate pesticide and water restriction on physiology and immunity in the passerine Zonotrichia capensis.

Impacts of an organophosphate pesticide and water restriction on physiology and immunity in the passerine Zonotrichia capensis.

Supporting dataset on the content of Cu, Ni Cd, Pb, Zn, Ag, Mg, Fe, Co and Ca in the carcass, gastrointestinal tract tissues and the whole body of nestlings of a small passerine bird, the Eurasian Reed Warbler Acrocephalus scirpaceus from an intensively fertilized fishpond habitat.

Supporting dataset on the content of Cu, Ni Cd, Pb, Zn, Ag, Mg, Fe, Co and Ca in the carcass, gastrointestinal tract tissues and the whole body of nestlings of a small passerine bird, the Eurasian Reed Warbler Acrocephalus scirpaceus from an intensively fertilized fishpond habitat.

Uropygial gland microbiota of nearctic-neotropical migrants vary with season and migration distance.

Symbiotic microbiota are important drivers of host behaviour, health, and fitness. While most studies focus on humans, model organisms, and domestic or economically important species, research investigating the role of host microbiota in wild populations is rapidly accumulating. Most studies focus on the gut microbiota; however, skin and other glandular microbiota also play an important role in shaping traits that may impact host fitness. The uropygial gland is an important source of chemical cues and harbours diverse microbes that could mediate chemical communication in birds, so determining the factors most important in shaping host microbiota should improve our understanding of microbially-mediated chemical communication. Hypothesizing that temporal, geographic, and taxonomic effects influence host microbiota, we evaluated the effects of season, migration distance, and taxonomy on the uropygial gland microbiota of 18 passerine species from 11 families. By sampling 473 birds at a single stopover location during spring and fall migration and using 16S rRNA sequencing, we demonstrate that season, followed by migration distance, had the strongest influence on uropygial gland microbial community composition. While statistically significant, taxonomic family and species had only weak effects on gland microbiota. Given that temporal effects on gland microbiota were nearly ubiquitous among the species we tested, determining the consequences of and mechanisms driving this seasonal variation are important next steps.

Long term study on blood glucose levels in wintering great tits Parus major in sites differing in artificial food availability

Blood glucose concentration is one of the fundamental biochemical indices in the physiology of birds and other vertebrates. Since glucose serves as the main fuel for metabolic energy, its proper level in the blood serum is crucial to the individual in terms of physiological health, which leads to applying it as an ecophysiological indicator. Such an indicator may be especially useful during energetically demanding periods, such as winter at northern latitudes. Therefore, the main objective of this paper was to examine the variation in blood glucose in wintering the great tits (Parus major) in nine consecutive winters at two sites that differed with respect to the amount of human-provided food. We assumed that trophic conditions resulting from the use of artificial feeders that vary between sites across the years would affect the metabolic performance of birds and their physiological condition, which should be reflected in the blood glucose levels of wintering individuals. We showed that both females and males were characterised by significantly higher glucose levels at the study site, which was characterised by the high accessibility to human-provided food sources (forest clearing) than at the site with low and irregular artificial feeding. The difference remained distinct throughout most of the winter seasons of the study. We also revealed a substantial variation between seasons in blood glucose concentration in the case of male great tits. In general, we show that avian blood glucose can be used as an ecophysiological indicator of the trophic conditions of the environment in which individuals from small passerine species winter.

New species and records of feather mites (Acariformes: Analgoidea) from endemic passerines (Aves: Passeriformes) in the Seychelles

Eight feather mite species were collected from five endemic passerine species in Fregate Island, Seychelles. Of them, two species are recorded in the Seychelles for the first time, and five species are described as new for science: Bicentralges zosteropis sp. n. (Trouessartiidae) from the Seychelles white-eye Zosterops modestus (type host) (Zosteropidae) and the Seychelles fody Foudia sechellarum (Ploceidae); Hadrophyllodes seychellensis sp. n. (Proctophyllodidae) from the Seychelles sunbird Cinnyris dussumieri (Nectariniidae); Montesauria sechellarum sp. n. (Proctophyllodidae) from the Seychelles magpie-robin Copsychus sechellarum; M. foudiae sp. n. (Proctophyllodidae) from F. sechellarum; and Mouchetia sechellarum sp. n. (Pteronyssidae) from F. sechellarum. Brief taxonomic comments are provided on corresponding feather mite genera and host-associations of recorded mite species.

Immune response accelerated telomere shortening during early life stage of a passerine bird, the blue tit (Cyanistes caeruleus).

Dealing with infections is a daily challenge for wild animals. Empirical data show an increase in reactive oxygen species (ROS) production during immune response. This could have consequences on telomere length, the end parts of linear chromosomes, commonly used as proxy for good health and ageing. Telomere length dynamics may reflect the costs associated with physiological responses. In this study, immune system of blue tit (Cyanistes caeruleus) nestlings was experimentally challenged through a polyinosinic:polycytidylic acid (poly I:C) injection, a synthetic double-stranded RNA that mimics a virus, activating the pathway of immune response triggered via the toll-like receptors 3. This path is known to form ROS downstream. Immune response was quantified by white cell counts in blood, while brain lipoperoxidation has been evaluated as an indicator of oxidative damage. Finally, individuals' telomere length shortening between days 8 and 15 after hatching was measured in erythrocytes. Challenged nestlings showed increased leukocyte number when compared with control (treated with a saline solution), lower brain lipid peroxidation (likely as a result of a compensatory mechanism after oxidative stress burst) and accelerated telomere shortening. These findings support the 'ageing cost of infections pathway' hypothesis, which supposes a role for infections in quick biological ageing.

Antimicrobial multiresistance in microorganisms of the Enterobacterales order isolated from exotic passerines from farms in the Metropolitan Region of Fortaleza.

The aim of this study was to assess the degree of antimicrobial resistance in strains of the Enterobacterales order isolated from exotic passerine birds originated from breeding facilities in the metropolitan region of Fortaleza. For this purpose, 104 strains of ten different bacterial species were used. To perform the antibiogram, ten antibiotics from eight pharmacological classes were employed. Among the main results, a high resistance rate was found for some antimicrobials, notably ampicillin (91.35%) and sulfamethoxazole-trimethoprim (47.12%). Additionally, relevant rates of resistance were also found for meropenem, a controlled-use antibiotic. Concerning the bacterial species, Escherichia coli showed resistance to nine out of the ten tested antibiotics, and out of the 24 strains used, eight showed resistance to at least three antibiotics, classified as multidrug-resistant. Thus, the results presented reinforce the need for surveillance regarding multidrug-resistant strains because, besides causing harm to animal health, they could also become a public health problem due to the zoonotic potential that some strains possess.