The Western Palearctic is one of the most investigated regions for avian haemosporidian parasites (Haemoproteus, Plasmodium and Leucocytozoon), yet geographic gaps in our regional knowledge remain. Here, we report the first haemosporidian screening of the breeding birds from Sardinia (the second-largest Mediterranean Island and a biodiversity hotspot), and the first for the insular Mediterranean in general. We examined the occurrence of haemosporidians by amplifying their mtDNA cytb gene in 217 breeding birds, belonging to 32 species. The total prevalence of infected birds was 55.3%, and of the 116 haplotypes recovered, 84 were novel. Despite the high number of novel lineages, phylogenetic analysis did not highlight Sardinia-specific clades; instead, some Sardinian lineages were more closely related to lineages previously recovered from continental Europe. Host-parasite network analysis indicated a specialized host-parasite community. Binomial generalized linear models (GLMs), performed at the community level, suggested an elevational effect on haemosporidian occurrence probability (negative for Haemoproteus; positive for Leucocytozoon) likely due to differences in the abundance of insect vectors at different elevations. Furthermore, a GLM revealed that sedentary birds showed a higher probability of being infected by novel haplotypes and long-distance migrants showed a lower probability of novel haplotype infection. We hypothesize that the high diversity of haemosporidians is linked to the isolation of breeding bird populations on Sardinia. This study adds to the growing knowledge on haemosporidians lineage diversity and distribution in insular environments and presents new insights on potential host-parasite associations.

Analysis of mitochondrial DNA from reed warblers sampled in Italy reveals that they are most similar to the nominate race of European Reed Warbler Acrocephalus scirpaceus scirpaceus. To fill gaps in our knowledge of the distribution of European/African Reed Warblers Acrocephalus scirpaceus/baeticatus in the Mediterranean region through genetic analysis of populations from the key biogeographic areas of Sicily, Sardinia and mainland Italy. We assessed the genetic placement of Italian reed warbler populations within a comprehensive dataset of this species complex, by sampling these birds from principal peninsular and insular breeding populations (for a total of 17 samples) and by comparing their mitochondrial cyt b sequences with those available in GenBank-NCBI. The final dataset included 171 cyt b sequences (763 base pair long). The analysis showed samples from Italy had a high similarity with the European Reed Warbler A. s. scirpaceus subspecies. This fills an important information gap in the phylogeography of the group. The genetic cohesion shown between Italian and other European populations may denote a structuring in at least three distinct refugia in the Western Palearctic: Iberia for A. baeticatus ambiguus, the Caucasus Mountains for A. s. fuscus, and both Italy and the Balkans for A. s. scirpaceus.

Implementing efforts to understand biogeographic distribution patterns and taxonomic limits within animal groups is crucial for addressing several challenges of modern zoology. Although avian phylogeography has been extensively investigated within the Western Palearctic, several families, such as shrikes, still display unresolved or neglected biogeographic patterns both between and within species, thus requiring further investigations. The Woodchat Shrike (Lanius senator) is a long-distance migratory species that exhibits three morphologically well-recognizable subspecies, whose boundaries have never been phylogenetically investigated. Here, we aimed to define the phylogeographic structure of Lanius senator throughout its breeding range and assess the genetic coherence with respect to the phenotypically described subspecies. We assembled a collection of 34 samples mainly from breeding populations of each subspecies and analysed them using four mtDNA and two nuDNA markers. We did not find clear phylogenetic structure in nuclear Ornithine Decarboxylase (ODC) and Myoglobin intron 2 (MYO), but all the four mtDNA loci (i.e., ND2, COI, cytb and CR) highlighted two main haplogroups: one including both the nominate subspecies L. s. senator and L. s. badius and a second one consisting of L. s. niloticus (the easternmost part of its range). Surprisingly, individuals phenotypically assigned to L. s. niloticus from Israel were genetically assigned to the senator/badius haplogroup. Moreover, genetic distances between haplogroups showed intermediate values between inter-intraspecies diversity usually reported for Passerines. We estimated a divergence time at ca. 890 kya (554–1.259 kya HPD). Our findings showed a mismatch in subspecies assignment using morphology and genetic information and a marked differentiation between the eastern L. s. niloticus and all other L. senator populations sampled.

Non‐native species are one of the greatest threats to biodiversity worldwide due to their direct and indirect effects on native communities. There are two opposing hypotheses to explain how non‐native species successfully establish outside their native range. The first posits that non‐native species are closely related to local native species through environmental filtering, which selects species with similar traits; the second posits that non‐native species are distantly related to native species in the area in which they establish due to limiting similarity, which minimizes competition. We assessed support for these two hypotheses by characterizing the functional trait space of terrestrial bird communities in Italian cities. We surveyed 220 points in breeding and winter periods along an urbanization gradient in six cities. We assessed whether two non‐native bird species, Rose‐ringed Parakeet Psittacula krameri and Monk Parakeet Myiopsitta monachus , conformed to either of the two opposing hypotheses by calculating functional diversity metrics (Functional Dispersion, i.e. quantification of the distribution of functional elements in the niche space, and Contribution, i.e. contribution of each species to the niche space) for each community. We then modelled these metrics in relation to the presence or absence of the two non‐native parakeet species along the urbanization gradient. We found that non‐native parakeet species probably established in the vacant functional niche space of urban bird communities. Our results support the hypothesis that limiting similarity allows the establishment of non‐native parakeets at the local scale by reducing competition with native species due to trait dissimilarity. Urban environments offer novel opportunities for the parakeets that are not exploited by the native species present. This insight into niche space processes in urban areas, which can act as centres for expansion of non‐native birds into other environments, can be used when implementing management strategies to enhance environmental filtering in these areas, thus reducing the chances of further establishment of non‐native species.

Implementing the effort in understanding biogeographic distribution patterns and taxonomic limits within animal groups is crucial for addressing several challenges of modern zoology. Although avian phylogeography has been deeply investigated within Western Palearctic, several families, such as shrikes, still display complicated or neglected biogeographic patterns both between and within species, thus requiring further investigations. The Woodchat Shrike ( Lanius senator ) is a long-distance migratory species that exhibits three morphologically well-recognizable subspecies, whose boundaries have never been molecularly investigated. Here, we aimed to define the phylogeographic structure of Lanius senator throughout its breeding range and assess the genetic coherence with the phenotypically described subspecies. We assembled a collection of 34 samples mainly from breeding populations of each subspecies and analyzed them at four mtDNA and two nuDNA markers. We did not find a clear phylogenetic structure with nuclear Ornithine Decarboxylase (ODC) and myoglobin intron 2 (MYO), while all the four mtDNA loci (i.e., ND2, COI, cytb and Control Region) highlighted two main haplogroups, one including both the nominate subspecies L. s. senator and L. s. badius and the second consistent with L. s. niloticus only from the easternmost part of the range. Surprisingly, individuals phenotypically assigned to L. s. niloticus from Israel were genetically assigned to the senator/badius haplogroup. Moreover, genetic distances showed intermediate values between inter-intraspecies diversity usually found in Passerines. We estimated a divergence time among the two haplogroups around 800 kya (549 - 1.259 kya HPD). Our findings showed a mismatch in subspecies assignment using morphology and genetic information and a marked differentiation between the eastern L . s. niloticus and all the other L. senator populations.