James A. Eaton

Biology, taxonomy and conservation status of the Short-tailed Green Magpie Cissa [t.] thalassina from Java

The Short-tailed Green Magpie Cissa thalassina, a member of an Asian lineage of uniquely coloured corvids, is represented by two subspecies, thalassina and jefferyi, that occur on the islands of Java and Borneo, respectively. The distinct Javan nominate form is poorly described in the literature and next to nothing is published on its biology and occurrence in the wild. We here document the biology and distribution of this taxon based on hitherto unpublished historical data and on our own fieldwork. We also analyse vocal data of jefferyi, thalassina and two other Cissa species and show that jefferyi and thalassina are well-differentiated, and that thalassina is bioacoustically more similar to another Cissa species from the Asian mainland. We also demonstrate important and significant biometric differences between jefferyi and thalassina that may reflect divergent adaptations to the environment, as well as plumage differences that may serve signalling functions. Finally, the application of a novel species delimitation test to our data suggests that jefferyi and thalassina deserve to be classified as biological species because their phenotypic divergence exceeds that found in many sympatric species. The revised taxonomic status of Javan thalassina invites a reconsideration of its threat status. Based on its restricted range, extreme rarity and threats by bird trapping and habitat destruction, we consider the Javan Green Magpie as globally Critically Endangered.

Species limits in Pteruthius (Aves: Corvida) shrike-babblers: a comparison between the Biological and Phylogenetic Species Concepts

The question of how to define a species continues to divide biologists. Meanwhile, the application of different species concepts has led to disparate taxonomic treatments that confound conservationists and other biologists. The most widely followed guidelines to species designation in avian and other vertebrate taxonomy are Ernst Mayr’s Biological Species Concept (BSC) and Joel Cracraft’s version of the Phylogenetic Species Concept (PSC). Although the BSC is considered to be more conservative in its assignment of species status, there is a lack of research demonstrating differences in taxonomic treatment between the BSC and the PSC with reference to a multi-taxon multi-trait study system. We examined the case of five traditionally recognized species of shrike-babbler (Pteruthius) that have recently been divided into 19 species under the PSC. Re-analyzing previous morphological and molecular data and adding new vocal data, we propose a BSC classification of 9 species. However, taking into consideration geographic gaps in the sampling regime, we contend that additional data will likely reduce discrepancies between the total numbers of species designated under the PSC and BSC. The current PSC species total is a likely overestimate owing to species diagnosis based on characters that erroneously appear to be unique to a taxon at low sample size. The current BSC species total as here proposed is a likely underestimate on account of the conservative designation of taxa as subspecies in equivocal cases, e.g. where BSC species status is potentially warranted but may be masked by insufficient data.

Vocal Trait Evolution in a Geographic Leapfrog Pattern: Speciation in the Maroon-Chinned Fruit Dove (Ptilinopus subgularis) Complex from Wallacea

Abstract Leapfrog patterns are a peculiar and little-understood phenomenon in which similar populations at either end of a geographic continuum are divided by dissimilar intervening populations. Leapfrog patterns may be important in allopatric speciation. Most documented cases of biological leapfrog patterns refer to morphological traits in passerine birds, and only few have been reported from outside the Andean region. More importantly, the biological basis of leapfrog patterns continues to elude biologists. We document a vocal leapfrog pattern—possibly the second such case documented—in the Maroon-chinned Fruit Dove (Ptilinopus subgularis) complex, adding to the few known examples of leapfrog patterns from outside the Neotropics and in non-passerines. P. subgularis is a Wallacean pigeon whose three taxa occur in a longitudinal continuum from Sulawesi in the west to the Sula Islands in the east. We used discriminant analysis and other statistical methods to demonstrate that terminal members of the complex differ in song from the geographically intermediate taxon but resemble each other more closely. Plumage in P. subgularis does not exhibit the same geographic distribution of variability, a pattern that agrees with the only other study reporting a vocal leapfrog pattern, and supports an earlier hypothesis that leapfrog patterns arise from stochastic phenotypic changes in geographically intermediate taxa. We combine the new insights on the distribution of vocal trait variation in P. subgularis with Pleistocene earth-historic information to revise species in the complex.

Bioacoustic and multi-locus DNA data of Ninox owls support high incidence of extinction and recolonisation on small, low-lying islands across Wallacea

Known for their rich biodiversity and high level of endemism, the islands of Wallacea serve as natural laboratories for the study of spatio-temporal evolution and patterns of species diversification. Our study focuses on the owl genus Ninox, particularly the Southern Boobook (N. novaeseelandiae) and Moluccan Boobook (N. squamipila) complexes, which are widely distributed across Australasia. We conducted bioacoustic and multi-locus DNA analyses of 24 Ninox owl taxa to evaluate relationships and levels of divergence within the two complexes and ultimately assess the relationship between patterns of taxonomic differentiation and bioclimatic factors. We found that taxa that are vocally and/or genetically distinct from populations on the Australian mainland are found on islands that are significantly larger and higher in altitude than taxa that are vocally and/or genetically indistinct from populations on the Australian mainland. This pattern suggests that taxa occurring on small, low-lying Wallacean islands are likely to be recent colonisers that have dispersed from Australia. Overall, our observations demonstrate that the genus Ninox is likely to have colonised the Wallacean region multiple times as small, low-lying islands undergo frequent extinction, whereas populations on large and high-altitude islands are more resilient.

Illegal trade pushing the Critically Endangered Black-winged Myna Acridotheres melanopterus towards imminent extinction

The Critically Endangered Black-winged Myna Acridotheres melanopterus is being pushed towards the brink of extinction in Indonesia due to continued demand for it as a cage bird and the lack of enforcement of national laws set in place to protect it. The trade in this species is largely to supply domestic demand, although an unknown level of international demand also persists. We conducted five surveys of three of Indonesia’s largest open bird markets (Pramuka, Barito and Jatinegara), all of which are located in the capital Jakarta, between July 2010 and July 2014. No Black-winged Mynas were observed in Jatinegara, singles or pairs were observed during every survey in Barito, whereas up to 14 birds at a time were present at Pramuka. The average number of birds observed per survey is about a quarter of what it was in the 1990s when, on average, some 30 Black-winged Mynas were present at Pramuka and Barito markets. Current asking prices in Jakarta are high, with unbartered quotes averaging USD 220 per bird. Our surveys of the markets in Jakarta illustrate an ongoing and open trade. Dealers blatantly ignore national legislation and are fearless of enforcement actions. Commercial captive breeding is unlikely to remove pressure from remaining wild populations of Black-winged Mynas. Efforts to end the illegal trade in this species and to allow wild populations to recover are urgently needed. We also recommend the immediate inclusion of Black-winged Mynas in Appendix III of CITES to allow for international support to Indonesia in clamping down on international trade of the species.

Nothing to laugh about – the ongoing illegal trade in laughingthrushes (Garrulax species) in the bird markets of Java, Indonesia

In ad hoc survey inventories of eight major bird markets in Java in 2014 and 2015, 615 individuals from nine species of the Garrulax genus were found for sale. The most numerous species was Sunda Laughingthrush Garrulax palliatus (215 individuals), followed by Chinese Hwamei G. canorus and Chestnut-capped Laughingthrush G. mitratus . Prices collected in Jakarta revealed that non-native species were the most expensive. Information from these and previous surveys indicate that prices for Sumatran Laughingthrush Garrulax bicolor appeared to have soared since 2007, suggesting increasing rarity of the species. We urge the Indonesian Government to take action against the illegal trade in laughingthrushes under existing laws, especially for the Rufous-fronted Laughingthrush Garrulax rufifrons which is listed on the national protected species list. We also recommend that the Sumatran Laughingthrush Garrulax bicolor be listed as a protected species under Indonesian law. As wild populations of Rufous-fronted Laughingthrush and Sumatran Laughingthrush are threatened by trade, we recommend an urgent review of the conservation status of both species on the IUCN Red List.

Speciation in Indo-Pacific swiftlets (Aves: Apodidae): integrating molecular and phenotypic data for a new provisional taxonomy of the Collocalia esculenta complex

White-bellied swiftlets of the Collocalia esculenta complex constitute a radiation of colony-breeding swifts distributed throughout the tropical Indo-Pacific region. Resolution of their taxonomy is challenging due to their morphological uniformity. To analyze the evolutionary history of this complex, we combine new biometric measurements and results from plumage assessment of museum specimens with novel as well as previously published molecular data. Together, this body of information constitutes the largest systematic dataset for white-bellied swiftlets yet compiled, drawn from 809 individuals belonging to 32 taxa for which new molecular, biometric, and/or plumage data are presented. We propose changing the classification of white-bellied swiftlets, for which two species are currently recognized, to elevate eight regional forms to species level, and we also describe two new subspecies. The ten taxa we recommend recognizing at the species level are: Collocalia linchi (Java to Lombok, Sumatran hills), C. dodgei (montane Borneo), C. natalis (Christmas Island), C. affinis (Greater Sundas, including the Thai-Malay Peninsula and Andaman-Nicobar Islands), C. marginata (Philippines), C. isonota (Philippines), C. sumbawae (west Lesser Sundas), C. neglecta (east Lesser Sundas), C. esculenta (Sulawesi, Moluccas, New Guinea, Bismarck Archipelago, Solomon Islands), and C. uropygialis (Vanuatu, New Caledonia). Future molecular and morphological work is needed to resolve questions of speciation and population affinities in the Philippines, Christmas Island, Wallacea and central Melanesia, and to shed light on historic diversification and patterns of gene flow in the complex.