Cranium of an Eocene/Oligocene pheasant-sized galliform bird from western North America, with the description of a vascular autapomorphy of the Galliformes

We describe the fossil cranium of a pheasant-sized galliform land bird from latest Eocene or earliest Oligocene marine rocks of the Jansen Creek Member, Makah Formation (Washington State, USA), which is the only three-dimensionally preserved cranium of a Paleogene representative of the Galliformes. The specimen was freed from a hard calcareous nodule with dilute formic acid. Micro-computed tomography provided further osteological details and a virtual cranial endocast. The fossil exhibits a plesiomorphic temporal morphology, lacking an ossified aponeurosis zygomatica, a feature characterizing some extant Cracidae and most Odontophoridae and Phasianidae. Overall, the fossil is most similar to the skull of the Asian phasianid taxon Arborophila, but this resemblance may well be plesiomorphic for a more inclusive clade. Still, we consider it possible that the fossil represents an archaic member of the Phasianoidea, in which case it would be the earliest record of this taxon from the New World. The fossil exhibits a previously unnoticed cranial autapomorphy of galliforms, a foramen in the temporal region that enables the vena profunda to enter the braincase, for which the name foramen temporale venosum is here introduced. Consistently present in all studied extant galliform taxa and absent in all other extant birds, this foramen enables a vascular connection between the brain and the ophthalmic rete, the latter playing an important role in thermoregulation of the avian brain.

Comparative analysis of annotation pipelines using the first Japanese white-eye (Zosterops japonicus) genome

Introduced into Hawaii in the early 1900s, the Japanese white-eye or warbling white-eye (Zosterops japonicus) is now the most abundant land bird in the archipelago. Here, we present the first Z. japonicus genome, sequenced from an individual in its invasive range. This genome provides an important resource for future studies in invasion genomics. We annotated the genome using two workflows – standalone AUGUSTUS and BRAKER2. We found that AUGUSTUS was more conservative with gene predictions when compared to BRAKER2. The final number of annotated gene models was similar between the two workflows, but standalone AUGUSTUS had over 70% of gene predictions with Blast2GO annotations versus under 30% using BRAKER2. Additionally, we tested whether using RNA-seq data from 47 samples had a significant impact on annotation quality when compared to data from a single sample, as generating RNA-seq data for genome annotation can be expensive and requires well preserved tissue. We found that more data did not significantly change the number of annotated genes using AUGUSTUS but using BRAKER2 the number increased substantially. The results presented here will aid researchers in annotating draft genomes of non-model species as well as those studying invasion success.

The contour feathers of water birds exhibit adaptations to the impact forces of diving, plunging and alighting

The contour feathers of water birds are well-known to show structural details in their distal one-third that optimally confer water repellency and resistance to water penetration. In this study, these details were further examined to see if they also provide resistance to the impact forces of diving and alighting. To this end, 49 species representing 37 water bird families were grouped into nine foraging niches before measurement of length, diameter, and spacing of their barbs. Twelve land bird species grouped into two foraging niches were included in this study for comparison. These measurements allowed the calculation of the ranges and medians for barb stiffness and vane deflection for each foraging niche. A phylogenetic ANOVA approach was followed to determine if the foraging niches for water and land birds explain differences in feather microstructure while accounting for phylogenetic relationships. There were no significant group aggregations for water or land birds confirming the statistical reliability of the ANOVA approach. Differences between the deflection parameter medians of water and land bird foraging niches proved significant demonstrating an evolutionary distinction between these groups. No such difference was observed for the two land bird foraging niches indicating similarity in feather structure. For the water birds, significance was found among all aquatic niches showing that differences in feather microstructure are associated with respect to differences in aquatic feeding niches. These findings support the notion that evolutionary adaptations of feather traits are significant across bird species and their respective foraging niches. The observed mechanical and morphological variations of feathers are therefore considered adaptations to different habitats and behavioral patterns.

Notes from the Santa Cruz Island Reserve

This chapter presents the author's field notes from the Santa Cruz Island Reserve. The author was particularly interested in studying island foxes. Lacking natural predators, island foxes tend not to find humans intimidating, indeed appearing tame even though they are technically wild. The island fox is currently on the rebound from endangered status. There were two thousand foxes on Santa Cruz Island in 1994, but canine distemper and golden eagle predation reduced the numbers to under 135 by 2000. The author was also interested in the endangered plants, the red-tailed hawk, the anise swallowtail, and the island scrub-jays. Not only is the island scrub-jay endemic, occurring only on the island, but it is also the only insular land bird in either the United States or Canada. The explanation for this is that scrub-jays seem incapable of crossing significant amounts of water.

Short-term movement patterns, population estimates and breeding biology of an island endemic bird, the Tristan Thrush

The Tristan Thrush Turdus eremita is the only land bird that survived human colonisation of the main island of Tristan da Cunha and is listed as “Near Threatened”. Population estimates are confounded by the thrushes’ inquisitive and gregarious nature as well as limited information on their movements. We report the first measures of nest densities on Nightingale Island: 6 nests·ha-1 in Phylica arborea woodland and 4–5 nests·ha-1 in tussock habitat, which suggests that the population is approximately double the previous estimate. At Inaccessible Island, we individually color ringed 110 thrushes over two months to track their short-term movements and estimate the local population size. Individuals moved up to 950 m along the coast, but 96% of resightings were < 100 m. A Bayesian data augmentation approach estimated that some 260 thrushes visited the core study area, a 200-m stretch of cobble and boulder beach where birds come to drink, bathe and forage. This result suggests that the population on Inaccessible Island also is substantially larger than reported previously. We estimate the total population to be 8000–15,000 Tristan Thrushes. The main need is a population estimate for the nominate subspecies on the main island of Tristan.

Prehistoric avifaunas from the Kingdom of Tonga

Avifaunas derived from Lapita archaeological sites excavated between 2004 and 2014 from four sites in the Vava'u Group and two on Tongatapu, Kingdom of Tonga are described, revealing birds encountered by the first human arrivals. A total of 741 identifiable bones revealed 24 avian taxa, among which terrestrial birds, especially rails, pigeons and parrots, were the most abundant. At a minimum, eight taxa, or 50% of the original non-passerine land bird diversity in the sample, are globally extinct. These include two megapodes (Megapodius alimentum and a larger unnamed megapode), three pigeons (a large Caloenas sp. indet., Didunculus placopedetes and Ducula shutleri sp. nov.), two rails (Hypotaenidia vavauensis sp. nov. and an unnamed one) and the parrot Eclectus infectus. The rail H. vavauensis was restricted to Vava'u and was flightless, with reduced wings, and larger than Hypotaenidia woodfordi of the Solomons, the largest congener hitherto found in the Pacific. The pigeon Du. shutleri was volant, but was the largest species in its genus and was widespread in the Kingdom. The evolution of Tongan avifaunas is related to varying ages (Pliocene to Pleistocene) of the island groups, where geological youth apparently precluded true giantism in the fauna.

Diversity and Abundance of Wet Land Bird Species in Lake Hora-Arsedi, Bishoftu, Ethiopia

The investigation of species diversity and abundance of birds in Lake Hora Arsedi Bishoftu town was conducted from September 2018 to July 2019. The aim of the study was to assess the diversity and abundance of bird species in Lake Hora Arsedi at Bishoftu town. Point count method was used to investigate the abundance of birds. Observation was conducted periodically walking along the study area early in the morning and late in the afternoon. Different diversity indices and statistical methods (Chi-square test and correlation) were used to analyze data collected during the field survey. Abundance of birds, their richness and evenness as well as birds` diversity recording were made. A total of 14 bird species grouped under 7 orders and 11 families were recorded. The month February had the lowest species diversity (H’= 0.33), species evenness (E = 0.13) and species richness (12). The highest species diversity, evenness and richness were recorded in March and April (H’=0.35), (E = 0.35) and (S = 14), respectively. Variation in abundance of birds was statistically significant between months. Abundance score of frequency of bird species was high during rainy season and uncommon are high during small rainy seasons using encounter rate. Lake Hora Arsedi has a number of natural and human induced bird attractant features. The area possesses favorable places for birds to nest, rest, roost and a good access to food as well as water resources. The study recommends the maintenance of bird watching records to monitor the effectiveness of management and to ensure early detection of any impact on bird numbers or behavior; conservation of Lake Hora Arsedi, its surroundings and making it free from human interference will enable us to conserve these valuable bird species. Hence, conservation measures by wildlife conservation authority and other concerned agencies are important to safeguard these species in the area.

Seasonal and directional dispersal behavior in an ongoing dove invasion

The dispersal behavior that underlies range expansions can be difficult to study. Eurasian Collared-Doves have staged independent northwestward invasions across both Europe and North America, reaching carrying capacity in Europe but continuing to increase exponentially in the Americas, where their dispersal behavior remains enigmatic. I used citizen science observations to investigate Eurasian Collared-Dove dispersal behavior along the North American Pacific coast, a natural barrier to land-bird dispersal. Using coastal and pelagic observations, I assessed the seasonality and directionality of dispersal and its prevalence across years. Dispersal flights peaked in spring, like in Europe, and were north-biased, consistent with northwestward initial colonization. A non-significant trend of increasing dispersal across years may reflect evolution of dispersal via spatial sorting and selection. These results inform management of this invasive dove, raise new questions about evolutionary mechanisms behind the invasion, and exemplify using citizen science to study dispersal behavior, a longstanding challenge in ecology.

Ornithological observations from Maratua and Bawean Islands, Indonesia

Indonesia’s many islands, large and small, make it an important center of avian diversity and endemism. Current biogeographic understanding, however, is limited by the lack of modern genetic samples for comparative analyses from most of these islands, and conservation efforts are hampered by the paucity of recent information from small islands peripheral to major, more commonly visited islands. In November and December 2016, we visited Maratua, an oceanic coral atoll 50 km east of Borneo, and Bawean, a volcanic island on the Sunda continental shelf 150 km north of Java, to survey birds and collect specimens for morphological and genetic analysis. We detected many of the birds on Maratua’s historical lists and added several new resident and migratory species. Notably, we did not detect the Maratua White-rumped Shama (Copsychus malabaricus barbouri). On Bawean, we found the forests to be nearly silent and detected remarkably few resident land-bird species overall. The severe population reduction of C. m. barbouri on Maratua and the drastic reduction of forest birds on Bawean probably result from overexploitation by the cage-bird trade in the first case and a combination of the cage-bird trade and pellet-gun hunting in the second.

Population status of four endemic land bird species after an unsuccessful rodent eradication on Henderson Island

SummaryInvasive rodents detrimentally affect native bird species on many islands worldwide, and rodent eradication is a useful tool to safeguard endemic and threatened species. However, especially on tropical islands, rodent eradications can fail for various reasons, and it is unclear whether the temporary reduction of a rodent population during an unsuccessful eradication operation has beneficial effects on native birds. Here we examine the response of four endemic land bird species on subtropical Henderson Island in the Pitcairn Island Group, South Pacific Ocean, following an unsuccessful rodent eradication in 2011. We conducted point counts at 25 sampling locations in 14 survey periods between 2011 and 2015, and modelled the abundance trends of all species using binomial mixture models accounting for observer and environmental variation in detection probability. Henderson Reed Warbler Acrocephalus taiti more than doubled in abundance (2015 population estimate: 7,194-28,776), and Henderson Fruit Dove Ptilinopus insularis increased slightly between 2011 and 2015 (2015 population estimate: 4,476–10,072), while we detected no change in abundance of the Henderson Lorikeet Vini stepheni (2015 population estimate: 554–3014). Henderson Crake Zapornia atra increased to pre-eradication levels following anticipated mortality during the operation (2015 population estimate: 4,960–20,783). A temporary reduction of rat predation pressure and rat competition for fruit may have benefitted the reed warbler and the fruit dove, respectively. However, a long drought may have naturally suppressed bird populations prior to the rat eradication operation in 2011, potentially confounding the effects of temporary rat reduction and natural recovery. We therefore cannot unequivocally ascribe the population recovery to the temporary reduction of the rat population. We encourage robust monitoring of island biodiversity both before and after any management operation to better understand responses of endemic species to failed or successful operations.