Aim Our understanding of population diversification in the lowlands of Sundaland has improved substantially over the last 20 years through phylogeographical study, but we know almost nothing about population diversification in the mountains of the region. Here, we apply genomic analysis and habitat modelling to the phylogeography of Chlorocharis emiliae, the Mountain Blackeye, an endemic montane bird of Borneo with a sky-island distribution, to investigate the structure and interconnectivity of its populations. In the process, we consider factors driving population diversification in the mountains versus lowlands on the island, and how population structure of C. emiliae compares with structure of previously studied lowland species.Location Borneo.Methods Using RAD-seq, we produced thousands of SNPs in 25 individuals from five sky-island populations of C. emiliae. These populations represent the species entire range across Borneo. Genetic structure and species tree analyses were applied to measure population relationships and connectivity. Ecological niche modelling was used to estimate habitat distributions during current and LGM time periods. ResultsWe identified slight to moderate genetic distinctiveness among all populations. Based on demographic models, isolation with migration was the main pattern of divergence, and the most admixture occurred among three populations in north-eastern Borneo: Kinabalu, Trus Madi and Murud. The most divergent population, Pueh, in north-western Borneo, has low genetic diversity and a small effective population size, is geographically isolated and has diverged in isolation without notable gene flow. These results, based on a large genomic dataset, contradict the evolutionary relationships identified in an earlier mitochondrial DNA study.Main conclusions Genomic phylogeographical comparisons indicate that diversification among sky-island populations of C. emiliae was driven largely by distance and historical habitat distribution, resulting in isolation but also some inter-population gene flow. During Pleistocene glacial events, cooler temperatures would have caused montane forest to descend and spread, thereby increasing connectivity among sky-island populations. However, despite increased montane habitat, the north-western population of Pueh remained isolated. This montane pattern contrasts with phylogeographical patterns in the Bornean lowlands, where populations often display evidence of vicariance followed by secondary contact.

The Mountain Black-eye (Chlorocharis emiliae) is an endemic white-eye (Zosteropidae) of Borneo with a unique ''sky island'' distribution. We compared mitochondrial ND2, ND3, Cytb, and control region DNA sequences (2,194 nucleotides) to study the phylogeographic relationships of five populations of this species that span its range: Mounts Kinabalu, Trus Madi, Murud, Mulu, and Pueh. These comparisons showed that black-eyes are divided into two main clades that correspond generally to subspecific morphological groups: one in Sabah, Malaysia (Kinabalu and Trus Madi), and one in Sarawak, Malaysia (Murud, Mulu, and Pueh). The genetic and morphologic subdivision of black-eyes disputes the expected merging of populations during the Last Glacial Maximum (LGM), when montane forest presumably expanded and provided the opportunity for currently isolated populations to intermingle. Instead the genetic aging of black-eye populations indicates they diversified long before the LGM, and either did not expand sufficiently in range during the LGM to reach one another, or were reproductively isolated by the time of the LGM and thus prevented from interbreeding. Moreover, the subdivision between black-eyes in Sabah and Sarawak means that this species (and probably several other montane species) has a phylogeographic structure remarkably similar to Borneo's lowland bird populations, which are presumed to have evolved under different paleo-geographic conditions. The similar phylogeographic pattern found in both montane and lowland species requires that we rethink the causes of bird population diversification on the island of Borneo. Keywords: Greater Sunda Islands, last glacial maximum, montane avifauna, phylogeography, refugia, sky islands, ZosteropidaePatrons de diversification aviaireà Bornéo: Le cas d'une espèce endémique, Chlorocharis emiliae RÉSUMÉ Chlorocharis emiliae est une espèce endémique de Zosteropidae de Bornéo ayant une répartition unique de type ''sky island.'' Nous avons comparé les séquences d'ADN mitochondrial ND2, ND3, Cytb, et de la région de contrôle (2,194 nucléotides) afin d'étudier les relations phylogéographiques de cinq populations de cette espèce qui couvrent toute son aire de répartition: Les Monts Kinabalu, Trus Madi, Murud, Mulu, et Pueh. Ces comparaisons ont montré que C. emiliae se divise en deux principaux clades qui correspondent généralement aux groupes morphologiques sousspécifiques: unà Sabah, en Malaisie (Kinabalu et Trus Madi) et unà Sarawak, en Malaisie (Murud, Mulu, et Pueh). La subdivision génétique et morphologique de C. emiliae conteste l'hypothèse de fusion des populations au cours du dernier maximum glaciaire (DMG), lorsque la forêt montagnarde s'est vraisemblablement développée et a fourni aux populations actuellement isolées l'occasion de se mélanger. Au lieu de cela, le vieillissement génétique des populations de C. emiliae indique qu'elles se sont diversifiées bien avant le DMG, et que leur aire de répartition ne s'est pas suffisammentélargie au cours du DMG pour se rejoindr...

Plumage colour studies using museum skins is one of the ways to understand species evolution and plumage polymorphism. The invaluable scientific information on a single historic specimen should be well-presented in the most regarded form of quality skin. However, aging plumage feathers are hypothetically susceptible to colour fading therefore doubting the relevant of using old specimens for plumage colour assessment. We examined the colour changes in 36 museum specimens by conducting series of Munsell colour scoring by comparing recent and old skins of mountain blackye (Chlorocharis emiliae), at Universiti Malaysia Sarawak (UNIMAS) and Sarawak Museum (SM). The year-gap of both sets of specimens ranged from 52 to 75 years. Eight plumage characters included in this study were crown, supercilium, auricular, mantle, rump, breast, belly and vent. The results revealed that the head (crown and auricular) and underparts (breast and vent) tend to fade extensively overtime compared to the upperparts. Therefore the results of this study support the earlier findings that aging plumage feathers are susceptible to colour fading.

A bird survey was conducted at the Sungai Kangkawat Research Station (117°3′34.593″E, 5°4′29.187″N), Imbak Canyon Conservation Area (ICCA), Sabah from 5th until 8th October, 2018. The objective of this survey was to produce a preliminary checklist of bird species in the study area. The primary method used was mist-netting with occasional observation from vocal and visual identification. A total of 30 mist-nets were deployed for 11 hours (0630-1730 hr.) for four consecutive days with a final accumulation of 1840 net/hours. Overall, 59 species comprising 23 families were recorded throughout the survey. Of these, 114 individuals were netted representing 41 species from 13 families. The most abundant species caught was the Little Spiderhunter Arachnothera longirostra with 26 individuals. Additionally, 18 species from 10 different families were identified via opportunistic sighting and vocalisation. This includes one Critically Endangered (Helmeted Hornbill, Buceros vigil), three Vulnerable (i.e., Rhinoceros Hornbill Buceros rhinoceros, Large-billed Blue Flycatcher Cyornis caerulatus and Blue-headed Pitta Pitta baudii and 20 other Near-threatened species. Four endemic species were recorded namely the Bornean Blue Flycatcher Cyornis superbus, White-crowned Shama Copsychus stricklandi, Black-headed Pitta Pitta ussheri and Blue-headed Pitta Pitta baudii. We expect higher diversity of birds in ICCA because the species accumulation curve did not reach an asymptote until the last day of sampling. This suggests additional trapping effort with point counts along predetermined transects should be considered for future surveys.

Understanding how birds utilised songs and calls to communicate among conspecifics is crucial for their survival, yet it remains an understudied area in bird ecology. We studied the influence of perch height selection on the vocalisation of Pied Triller, a common garden bird, in two suburban landscapes namely Pustaka Negeri Sarawak Recreational Park, Kuching and Universiti Malaysia Sarawak campus, Kota Samarahan from October 2018 to February 2019. Using a Marantz recorder connected to a parabolic reflector, we recorded calls and songs during morning (0630-1030 hr) and late afternoon (1600-1830 hr). Perch object, tree species, roost substrate and perch height from the ground were identified and measured. Clear and good quality spectrograms were used directly to describe song and call types. Photos and video recordings were analysed to describe perch behaviour. The vocal output representatives were then matched to the corresponding behaviour displayed. Our results revealed that Pied Trillers emit four different vocal outputs namely (i) song type, (ii) call type A, (iii) call type B and (iv) call type C. A total of nine behaviours were observed, of which the perch-hop behaviour was observed the most from both male and female Pied Trillers (33.71%), followed by perching (29.21%), foraging (20.22%), preening (7.78%), defecating (2.25%), eating (2.25%), roosting (2.25%), bill wipe (1.12%) and flight (1.12%). They prefer to roost on high perch to emit calls compared to songs. This probably suggest that Pied Triller prioritised vocal transmission and signalling to avoid being masked by surrounding anthropogenic noises and to avoid being conspicuous to potential predators. The most frequently visited perch object was the Weeping fig tree, Ficus benjamina.   Keywords: Call, perch height, Pied Triller, song, suburban landscapes