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Animal movement and behaviour is fundamental for ecosystem functioning. The process of seed dispersal by frugivorous animals is a showcase for this paradigm since their behaviour shapes the spatial patterns of the earliest stage of plant regeneration. However, we still lack a general understanding of how intrinsic (frugivore and plant species traits) and extrinsic (landscape features) factors interact to determine how seeds of a given species are more likely to be deposited in some places more than in others. We develop a multi-species mechanistic model of seed dispersal based on frugivore behavioural responses to landscape heterogeneity. The model was fitted to data from three-years of spatially-explicit field observations on the behaviour of six frugivorous thrushes and the fruiting patterns of three fleshy-fruited trees in a secondary forest of the Cantabrian range (N Spain). With such model we explore how seed rain patterns arise from the interaction between animal behaviour and landscape heterogeneity. We show that different species of thrushes respond differently to landscape heterogeneity even though they belong to the same genus, and that provide complementary seed dispersal functions. Simulated seed rain patterns are only realistic when at least some landscape heterogeneity (forest cover and fruit abundance) is taken into account. The common and simple approach of re-sampling movement data to quantify seed dispersal produces biases in both the distance and the habitat at which seeds arrive. Movement behaviour not only affects dispersal distance and seed rain patterns but also can affect frugivore diet composition even if there is no built-in preference for fruiting species. In summary, the fate of seeds produced by a given plant species is strongly affected by both the composition of the frugivore assemblage and the landscape-scale context of the plant location, including the presence of fruits from other plants (from the same or different species).

The distribution of a species reflects its ecological adaptability and evolutionary history, which is shaped by the environment and represents a dynamic area subject to anthropogenic environmental change. We used the MaxEnt algorithm to construct ecological niche models for four thrush species within the Turdus genus; T. amaurochalinus , T. chiguanco , T. falcklandii and T. rufiventris . These models were used to predict the potential geographic distributions of these species that are expanding their ranges in South America. Using occurrence records, we estimated currently occupied areas for each species. We also identified suitable habitats and projected possible areas to be colonized by the four species at continental scale . Temperature annual range had the highest influence for T. falcklandii , while human modification was the main variable explaining the distribution of the other three species. The potential distribution area ranged from 2.5 million km 2 for T. falcklandii to nearly seven million km 2 for T. amaurochalinus. Large proportions of suitable area remain unoccupied by all four species, being 50% for T. amaurochalinus and T. rufiventris , and about 70% for T. chiguanco and T. falcklandii . Anthropogenic disturbances, such as habitat loss and ecosystem transformation, lead to non-random species extinction and biotic homogenization, highlighting the importance of predictive models as valuable tools for informing mitigation policies and conservation strategies. Thrushes are progressively expanding their ranges, and the colonization of new habitats could bring new challenges.

Plasmodium spp. are haemosporidian protozoans that alternate their live cycles between bloodsucking Culicidae dipterans and vertebrate hosts (mammals, reptiles, and birds). In birds, these parasites are the causative agents of the so-called avian malaria, a disease associated with considerable declines and extinctions in the avifauna in different geographical regions. In this work, we applied a multidisciplinary approach, light microscopy and cytochrome oxidase b (cyt b) gene sequence analysis, for characterization of Plasmodium spp. found in association with wild birds of the genus Turdus, collected in Atlantic forest fragments of southeastern Brazil. From the total 90 analyzed birds, 58 (47 Turdus rufiventris, 9 Turdus leucomelas, 1 Turdus albicollis, and 1 Turdus flavipes) were positively infected with Plasmodium unalis, a haemosporidian that was previously detected in Turdus fuscater in Colombia and in penguins in Brazil, but has never been found in association with these Turdus species of this present work. Moreover, all 7 new sequences of P. unalis cyt b gene clustered into a monophyletic clade with previously characterized P. unalis sequences with a mean genetic divergence of 1.6% and with a maximum divergence of 3.1%, indicating for a high degree of intraspecific polymorphism within this parasitic species. Together, our data highlight the existence a high degree of intraspecific variation within P. unalis and highlight the importance of integrative taxonomy to an accurate identification and characterization of avian haemosporidian parasites.

A new coccidian species (Protozoa: Apicomplexa: Isospora) is described parasitizing white-necked thrushes Turdus albicollis Vieillot, 1818; rufous-bellied thrushes Turdus rufiventris Vieillot, 1818; pale-breasted thrushes Turdus leucomelas Vieillot, 1818; and yellow-legged thrushes Turdus flavipes Vieillot, 1818 from 3 different localities in Brazil. Isospora sabiai n. sp. has oocysts that are subspherical to ellipsoidal, 20.9 × 18.6 μm, with smooth, delicate, bilayered wall, ∼1.1 μm thick. Micropyle inconspicuous or imperceptible. Oocyst residuum absent, but small polar granules rounded or comma-shaped are present. Sporocysts are elongate ellipsoidal to reniform, 16.5 × 9.2 μm. The Stieda body is knob-like. Sub-Stieda body rounded to conical, sometimes homogeneous with the Stieda body. Sporocyst residuum is present, usually as a cluster of numerous granules. Sporozoites are vermiform with 2 refractile bodies. The oocysts and sporocysts of I. sabiai n. sp. are uniform in the proportionality of width on length, but exhibited different patterns of size associated with each host species; therefore, an ecological discussion is introduced aimed at associating these morphometrical patterns of the oocysts with the habits of the different species of thrushes. This is the seventh isosporoid coccidian reported from New World turdids.

For the first time, studies have been conducted aiming at the diversity of the oribatid mites (Oribatida) that inhabit the nests of open-nesting birds of the genus thrushes (Turdus), particularly fieldfare (T. pilaris Linnaeus, 1758) and redwing (T. iliacus Linnaeus, 1766), in the taiga forests of the European north-east. Long-term observations were carried out in the green belt of the city of Syktyvkar (N 61°40′ E 50°50′) in 2021–2025. Among 168 studied thrush nests (fieldfare—138, redwing—30), 1982 specimens of oribatid mites of 35 species from 33 genera and 26 families were found. The nests of thrushes contain a mixed fauna of oribatid mites, including the following: (a) Soil species that obviously enter the nest with building materials collected by birds from the soil surface. These are epigeic species such as Eupelops plicatus, Neoribates aurantiacus, and Chamobates pusillus; hemi-edaphic species such as Heminothrus peltifer; and euedaphic species such as Oppiella nova and Quadroppia quadricarinata. (b) Tree-dwelling species that have been recorded as inhabiting epiphytic lichens in the European north-east, such as Ameronothrus oblongus, Ceratoppia quadridentata, Oribatula propinqua, Trichoribates berlesei, and Diapterobates oblongus. (c) Eurybiont species such as Tectocepheus velatus, Scheloribates laevigatus, and Oribatula tibialis. An increase in the number and diversity of oribatid mites was noted in nests collected after the end of the nesting period and the flight of chicks compared to nests collected in the spring (overwintered nests).

Apart from some species that reuse their nests regularly, the reuse of open nests is an uncommon phenomenon in the majority of species, especially the passerines. The interspecific reuse of open nests has rarely been described. Here I examine a case of such reuse in thrushes, specifically the reuse of a Fieldfare's (Turdus pilaris) nest by a Song Thrush (Turdus philomelos). A total of 14 Song Thrush nests with eggs were found in an orchard; more than half of these clutches were unsuccessful. Breeding success in the Song Thrush in the orchard was 29% for first clutches/broods and 60% for second clutches/broods. Eleven Fieldfare nests contained clutches: 87% of them were unsuccessful. Breeding success was as low as 14% in the case of first clutches/ broods, and no second clutches/broods were successful. Having reviewed the hypotheses relating to nest reuse, I consider that this case was not brought about by a lack of suitable nesting sites. It was, however, advantageous in that the time and costs of building a new nest were much reduced, given that the nesting territory was of high quality, and that the nesting season is short and breeding success low.

The taxonomy of Hauxwell's Thrush (Turdus hauxwelli) with respect to its relationship to the Cocoa Thrush (Turdus fumigatus) has been complicated. A confounding factor has been the morphological variation reported within T. hauxwelli and the apparent geographic overlap of the two taxa. Recent evidence shows that some of these factors may be explained by the existence of a cryptic, syntopic species, very similar in plumage to T. hauxwelli. The new species differs in minor plumage characters, in soft-part colors, and (especially) in voice. On the basis of vocal and molecular data, we propose that the new thrush is not particularly closely related to the T. fumigatus/hauxwelli complex but rather is the western Amazonian member of the Spectacled Thrush (T. nudigenis) complex. Our molecular phylogeny suggests that the new species is sister to the Unicolored Thrush (T. haplochrous) and also that the Ecuadorian Thrush (T. maculirostris) should be considered a species separate from the Spectacled Thrush. In the absence of modern, data-rich specimens, the new thrush might well have remained unknown. This hidden taxon provides yet another case that argues strongly for continuing the tradition of general specimen collection. Having removed the new species as a source of confusion, we suggest that a reevaluation of the species status of T. hauxwelli with respect to T. fumigatus is in order.

The failure of breeding attempts is a major hindrance to bird reproduction, making nest site choice under strong selective pressure. Urbanization may offer lower risk of nest predation to certain bird species, but the impact of using anthropogenic structures as nesting sites on parental fitness is seldom studied. We studied the effect of anthropogenic substrates and brood parasitism by the shiny cowbird Molothrus bonariensis on the nest success of a Neotropical songbird, the pale‐breasted thrush Turdus leucomelas. We monitored 263 nesting attempts between 2017 and 2020 to estimate daily survival rate (DSR), which represents the probability of a given nest surviving until the next day. DSR was modelled as a response variable in function of substrate type (plants as ‘natural' or human buildings as ‘artificial') and brood parasitism as fixed factors, using as covariates year, a linear and a quadratic seasonal trends. Additionally, we tested the effect of these same explanatory variables on the number of fledglings per nest using a generalized linear mixed‐effects model. Most nests (78.7%) were placed in artificial substrates and apparent nest success (i.e. the percentage of nesting attempts that produced at least one thrush fledgling) was higher in artificial (50.2%) than in natural substrates (37.5%). DSR was higher for nests in artificial than in natural substrates regardless of cowbird parasitism, whereas the number of fledglings per nest was higher both in artificial substrates and for nests without cowbird parasitism. We highlight that nesting in buildings significantly increases parental fitness in pale‐breasted thrushes, which may favor their settlement in cities and potentially drive the evolution of this breeding behavior in urban birds.

Illegal killing/taking of birds is a growing concern across the Mediterranean. However, there are few quantitative data on the species and countries involved. We assessed numbers of individual birds of each species killed/taken illegally in each Mediterranean country per year, using a diverse range of data sources and incorporating expert knowledge. We estimated that 11–36 million individuals per year may be killed/taken illegally in the region, many of them on migration. In each of Cyprus, Egypt, Italy, Lebanon and Syria, more than two million birds may be killed/taken on average each year. For species such as Blackcap Sylvia atricapilla, Common Quail Coturnix coturnix, Eurasian Chaffinch Fringilla coelebs, House Sparrow Passer domesticus and Song Thrush Turdus philomelos, more than one million individuals of each species are estimated to be killed/taken illegally on average every year. Several species of global conservation concern are also reported to be killed/taken illegally in substantial numbers: Eurasian Curlew Numenius arquata, Ferruginous Duck Aythya nyroca and Rock Partridge Alectoris graeca. Birds in the Mediterranean are illegally killed/taken primarily for food, sport and for use as cage-birds or decoys. At the 20 worst locations with the highest reported numbers, 7.9 million individuals may be illegally killed/taken per year, representing 34% of the mean estimated annual regional total number of birds illegally killed/taken for all species combined. Our study highlighted the paucity of data on illegal killing/taking of birds. Monitoring schemes which use systematic sampling protocols are needed to generate increasingly robust data on trends in illegal killing/taking over time and help stakeholders prioritise conservation actions to address this international conservation problem. Large numbers of birds are also hunted legally in the region, but specific totals are generally unavailable. Such data, in combination with improved estimates for illegal killing/taking, are needed for robustly assessing the sustainability of exploitation of birds.

The unique structure of the egg allows for efficient reproduction on land. Although the functions of the egg are ensured by the concomitant cooperation of all its structures, the eggshell also plays a significant role. Apart from maintaining an aqueous environment within the egg along with controlled gas exchange, the color and pigmentation pattern of eggshell contributes to identification and protection. As a result of all these functions, the structure, shape, and pigmentation of eggshell greatly vary across the class of birds, and understanding these three variability-determining factors may aid in better interpretation of evolutionary mechanisms. In this study, we analyzed for the first time the structure, mineral composition, and characteristics of the pigmentation of blackbird ( Turdus merula ) and song thrush ( Turdus philomelos ) eggshells. The shell of blackbird eggs is much thicker compared to the shell of song thrush eggs which is due to a much thicker crystalline and palisade layers. In both species, strongly elongated mammillary knobs are observed, which create a large space between the mineralized shell and the egg membranes. The blackbird egg shell has a higher water vapor conductivity which is due to the larger diameter of the circle and the surface area of individual pores. The primary compound entering the mineral composition of the shell in both species is CaCO 3 however, the thrush egg shells contained more Mg in all layers except the crystalline layer, and S in the crystalline and palisade layers. The two species clearly differ in the size and distribution of pigment spots on the eggshell. We suppose that the differences in shell structure and pigmentation presented in this study may in the future provide a basis for explaining the reasons for the much lower reproductive efficiency of song thrush compared to blackbird.