Mitochondrial DNA usually shows low sequence variation within and high sequence divergence among species, which makes it a useful marker for phylogenetic inference and DNA barcoding. A previous study on the common redstart (Phoenicurus phoenicurus) revealed two very different mtDNA haplogroups (5% K2P distance). This divergence is comparable to that among many sister species; however, both haplogroups coexist and interbreed in Europe today. Herein, we describe the phylogeographic pattern of these lineages and test hypotheses for how such high diversity in mtDNA has evolved. We found no evidence for mitochondrial pseudogenes confirming that both haplotypes are of mitochondrial origin. When testing for possible reproductive barriers, we found no evidence for lineage‐specific assortative mating and no difference in sperm morphology, indicating that they are not examples of cryptic species, nor likely to reflect the early stages of speciation. A gene tree based on a short fragment of cytochrome c oxidase subunit 1 from the common redstart and 10 other Phoenicurus species, showed no introgression from any of the extant congenerics. However, introgression from an extinct congeneric cannot be excluded. Sequences from two nuclear introns did not show a similar differentiation into two distinct groups. Mismatch distributions indicated that the lineages have undergone similar demographic changes. Taken together, these results confirm that deeply divergent mitochondrial lineages can coexist in biological species. Sympatric mtDNA divergences are relatively rare in birds, but the fact that they occur argues against the use of threshold mtDNA divergences in species delineation.

A challenging problem in the field of avian ecology is deriving information on bird population movement trends. This necessitates the regular counting of birds which is usually not an easily-achievable task. A promising attempt towards solving the bird counting problem in a more consistent and fast way is to predict the number of birds in different regions from their photos. For this purpose, we exploit the ability of computers to learn from past data through deep learning which has been a leading sub-field of AI for image understanding. Our data source is a collection of on-ground photos taken during our long run of birding activity. We employ several state-of-the-art generic object-detection algorithms to learn to detect birds, each being a member of one of the 38 identified species, in natural scenes. The experiments revealed that computer-aided counting outperformed the manual counting with respect to both accuracy and time. As a real-world application of image-based bird counting, we prepared the spatial bird order distribution and species diversity maps of Turkey by utilizing the geographic information system (GIS) technology. Our results suggested that deep learning can assist humans in bird monitoring activities and increase citizen scientists’ participation in large-scale bird surveys.

While the function of ornaments shaped by sexual selection is to attract mates or drive off rivals, these signals may also evolve through social selection, in which the social context affects the fitness of signallers and receivers. Classical ‘mate choice’ experiments often reveal preferences for ornaments, but few studies have considered whether these are strictly sexual or reflect general social preferences. Indeed, an alternative possibility is that ornaments evolve through ‘non-sexual social selection’ (hereafter ‘social selection’). We examined the role of ornamentation (yellow ventral patch) and familiarity (individuals recognize group mates with which they have had previous interactions) on mate choice (opposite-sex stimuli preference) and social choice (same-sex stimuli preference) in both male and female white-eyed bulbuls (Pycnonotus xanthopygos). In the mate choice test, females preferred unfamiliar males with increased yellow. There were no biologically important differences in male preferences based on familiarity or intensity of patch colour. In the social choice test, females preferred to associate with familiar females. Males preferred to associate with familiar males but also preferred to associate with less ornamented males. Our results suggest that ornamentation and familiarity are important features, playing different roles in males and females, in both social and sexual selection processes.

Türkiye is considered an important evolutionary area for Chukar partridge (Alectoris chukar), since it is both a potential ancestral area and a diversification center for the species. Using 2 mitochondrial (Cty-b and D-loop) and 13 polymorphic microsatellite markers, we investigated the geographic genetic structure of A. chukar populations to determine how past climatic fluctuations and human activities have shaped the gene pool of this species in Türkiye. Our results indicate, firstly, that only A. chukar of the genus Alectoris is present in Türkiye (Anatolia and Thrace), with no natural or artificial gene flow from congenerics. Secondly, the geographic genetic structure of the species in Türkiye has been shaped by topographic heterogeneity, Pleistocene climatic fluctuations, and artificial transport by humans. Third, there appears to be three genetic clusters: Thracian, Eastern, and Western. Fourth, the post-LGM demographic expansion of the Eastern and Western populations has formed a hybrid zone in Central Anatolia (~8 kyBP). Fifth, the rate of China clade-B contamination in Türkiye is about 8% in mtDNA and about 12% in nuDNA, with the Southeastern Anatolian population having the highest contamination. Sixth, the Thracian population was the most genetically distinct, with the lowest genetic diversity and highest level of inbreeding and no China clad-B contamination. These results can contribute to the conservation regarding A. chukar populations, especially the Thracian population.

The offspring sex ratios and breeding success in a population of the Great Tit, Parus major, in Antalya, southern Turkey, were determined. Feathers were collected from nestlings, un-hatched eggs and dead nestlings, and the sex was identified through CHD genes by amplifying P8 and P2 primers. The primary sex ratio (at conception) was 54% male and 46% female, the secondary sex ratio (at hatchling) was 52% male and 48% female, and the tertiary sex ratio (at fledging) was 53% male and 47% female. The predominance of males was statistically not significant (p>0.05) in all three phases. Hatchling success was found to be 87.3% in males and 100% in females; fledging success 96.1% in males and 91.6% in females, and general breeding success 85% in males and 93% in females. The mean number of fledglings per pair was significantly higher in first broods (p<0.05). Approximately the same number of males and females (0.53/0.47) fledged, thus resulting in a balanced sex ratio that may imply stable population structures.