The stomach contents (food and ingested plastics) of Laysan Albatross Phoebastria immutabilis and Black-footed Albatross P. nigripes were examined by necropsy analysis of birds caught as bycatch in the pelagic longline fisheries in the Western North Pacific. The contents were classified separately for the proventriculus and gizzard. Undigested fish and cephalopods were found in the proventriculus, while hard objects such as cephalopod beaks, plastics, and pebbles were found in the gizzard. This indicates that the retention time of soft tissues in fish or cephalopods differs from that for hard objects. The main prey of both albatrosses consisted of mesopelagic cephalopods such as Cranchiidae, Gonatidae, Histioteuthidae, and Onychoteuthidae species. Laysan Albatrosses also foraged on small teleosts (Japanese Anchovy Engraulis japonicus and some Myctophidae fishes) as major prey items. The estimated dorsal mantle length of cephalopods preyed upon by the albatrosses was below 200 mm, which was smaller than the mature sizes of those cephalopods and the size class mainly preyed upon by cetaceans. This implies that the albatrosses may forage on immature cephalopods floating in the surface layer. Ingested plastics were found in 71.8% of Laysan and 31.8% of Black-footed Albatrosses and plastic fragments were the most abundant.
The present study was conducted to identify the effect of urban and natural areas on nesting and breeding success of Rose-ringed Parakeet. Nests of Rose-ringed Parakeet were monitored using a combination of camera surveillance and direct observations along transect lines. Cavity availability and use was compared between natural and urban areas. A total of 171 cavities were located, of which 106 contained active nests. The number of available cavities and the proportion occupied were both higher in natural areas than in urban areas. A uniform/cosine model estimated that mean nest density was greater (P<0.05) in natural areas (136 nests/km2) than in urban areas (130 nests/km2). The preferred trees used for nesting were Banyan Ficus benghalensis (22.8%) followed by Chinaberry Tree Meliaazedarach (20.4%), Paper Mulberry Broussonetia papyrifera (14.6%), Chir Pine Pinus roxburghii (14.6%), Southern Blue Gum Eucalyptusglobulus (11%), Mango Mangifera indica (9.3%), and White Mulberry Morus alba (12%). The greatest number (P<0.05) of successful breeding cavities was recorded in the middle of trees (42.5%) at heights of 6.1–9 m (72.6%) above ground. Mean cavity depths were significantly greater (P<0.05) in urban areas (9.95±0.5 cm) than in natural areas (8.71±2.1 cm), while mean entrance diameter was 6.19±1.9 cm in natural areas and 5.65±0.2 cm in urban areas. Clutches of five eggs were the most common. Hatchling and fledgling successes were higher in natural areas than urban areas, with egg survival probability (70.0%) and nestling survival probability (94.0%) higher in natural areas than in urban areas (37% and 60%) respectively. It is concluded that the breeding success of Rose-ringed Parakeet varies between urban and natural areas.
Landscape features, such as rivers, can act as geographical barriers to dispersal and gene flow and thus influence the population structure of some species. In this study, tissue samples were collected from 73 Hume's Pheasant Syrmaticus humiae, from six localities in Guangxi and Guizhou provinces, China, to examine the influence of rivers in landscape structure on genetic diversity and structure based on 12 microsatellite loci. Results indicated a high genetic diversity in Hume's Pheasant. Individuals from populations in Tianlin, Longlin and Xilin counties (TXL) (three geographically proximate populations) tended to form a genetic cluster, distinct from three other geographically proximate populations 100 km to the west in Pojie town (PJ), Luodian county (LD) and Leye county (LX), which showed more mixing and were less genetically distinct. Using simulated Markov-switching VAR (MSVAR), we found that the median population sizes of the posterior distributions were approximately 3,715 individuals for N0, and approximately 100,000 for N1, indicating that Hume's Pheasant experienced a significant genetic bottleneck 4,800 years ago, possibly due to human activity. Hume's Pheasant shows female-biased dispersal. The results of STRUCTURE and GENELAND indicate that Nanpan River, Hongshui River and national road G324 act as potential genetic barriers for Hume's Pheasant in Guangxi and Guizhou provinces. In addition, genetic distinctiveness has persisted despite population declines of the Hume's Pheasant due to the bottleneck approximately 5,000 years ago and population declines in the last 100 years.
High quality roosts play a significant role in species' population survival and such information is scarce for many gull species. In this context, identifying factors that influence roost-site selection by gulls, and the extent to which they do so, as well as suggesting appropriate management strategies to conserve coastal habitats along the Central Asian Flyway, are urgent necessities. We conducted near-shore surveys along a 121–km stretch of India's west coast between January 2015 and April 2018 to assess roost-site selection by wintering gulls. At select sites, we also conducted population assessments from established vantage points during low tide using a photograph-based total count method. We recorded five species of gulls. Generalized Linear Models showed that three habitat variables, namely the number of sandbanks, extent of sandbanks, and distance to fish-landing centres, strongly influenced roost-site selection by gulls. Ideal estuaries for gull roosting included more than two sandbanks that spanned more than eight hectares, and were within two kilometres of fish-landing centres. Zero-inflated count models revealed strong site-fidelity among gulls and showed that the sampling covariates did not influence the detection of gulls in already known sites. We recorded eight percent of the 1% biogeographic population of Brown-headed Gull, three percent of that for Pallas's Gull and two percent of that for Slender-billed Gull. Encouraging sustainable use of coastal areas for recreational activities, curbing sand mining, and including three sites (Karli, Mitbav and Mochemad) in Sindhudurg district under India's protected area network, as Community Conservation Reserves, may help conserve the wintering population of gulls along the Indian coast.
The purpose of this study was to evaluate the selection of foraging habitats by the Lesser Kestrel Falco naumanni during the different phases of breeding and the post breeding season on the Plain of Thessaly, central Greece. Foraging habitat selection by the species was recorded by direct visual observation in 2014 and 2015 during their presence in the area. Habitat selection was analyzed using the Savage selectivity index. The results indicate that Lesser Kestrels were likely to positively select fallow and set-aside land from pair formation to the pre-migratory phase, but with some annual variation. Legumes (Alfalfa) and cereals were also positively-selected crop categories, whereas cotton and other kinds of cultivation were significantly avoided. During the incubation and chick rearing phase, cereals (the most widespread form of cultivation in the area), were positively selected, which highlights the importance of these crops during this critical breeding phase. Prey abundance and availability, which depend on farming practices, seem to be the main reasons for the periodic variation in the species' habitat selection in the area.
Understanding the patterns and drivers of bird species composition and diversity outside Protected Area networks is essential to develop landscape-level conservation strategies. The Western Ghats' coffee plantations of India form an important agro-ecosystem and help maintain a significant portion of regional avian diversity. However, knowledge of the composition and functional diversity of birds in differently managed coffee plantation is lacking from the Western Ghats. In this study, we compared the composition and functional diversity of resident birds between shade and open coffees plantations. We counted 3,846 birds of 87 species, and found species richness to be higher in shade (78 species) than in open coffee plantations (55 species). Interestingly, 32 species were unique to shade and nine were unique to open coffee plantations, with 46 species found in both types of plantation. Overall species composition and functional diversity were different in differently managed plantations. Species richness and abundance (birds/point/visit) were higher in shade coffee, reflecting the availability of multiple strata and habitat heterogeneity. Results revealed that different farm management practices can affect functional bird richness and its abundance in coffee plantations. Therefore, retaining shade-trees of native varieties in coffee plantations is important for supporting high functional diversity, richness, and abundance of birds in the coffee plantation of the Western Ghats.
Mediterranean wetlands represent a broad variety of natural resources with a huge role in the maintenance of biological diversity. Waterbirds are significant components of this diversity. Among them, the Eurasian Coot Fulica atra is a key species when studying the correlations and interactions between waterbirds and environmental variables, because of its abundance, ease of detection, and relation with some basic aspects of the functioning of wetlands. The present study aimed to analyse the annual and seasonal variation in populations of Eurasian Coot in 31 wetlands in Andalusia, southern Spain, from 2003 to 2008, paying particular attention to correlations with biotic and abiotic variables. The results showed a positive correlation between water depth and coot abundance, while a negative relationship was observed with salinity and no correlation was observed between wetland size and coot abundance. These environmental variables, together with submerged macrophyte coverage, stand out as playing important roles in the use of habitat by coots in Andalusian wetlands.
The Scarlet-backed Flowerpecker Dicaeum cruentatum (Dicaeidae, Passeriformes), a sedentary species of Southeast Asia, is among the smallest passerine birds (5–6 g). Despite its very small size, it feeds mainly on plant foods, such as berries, nectar, and green seeds. We found that in conditions of likely food shortage Scarlet-backed Flowerpeckers were able to greatly reduce their metabolic rate at a relatively high ambient temperature (26–28°C). This is within the thermoneutral zone of most tropical birds, although slightly cooler than the normal lower critical temperature of flowerpeckers. In this state, the resting metabolic rate (RMR) of three individual, free-living Scarlet-backed Flowerpeckers from Vietnam averaged 1.57 mL O2/g*h, which was 3.4 times lower than their non-torpid RMR, measured at the same ambient temperature (Ta=~27°C) and 2.5 time lower than their basal metabolic rate (BMR) measured at Ta=~31°C. We did not measure the body temperature (Tb) of these individuals, but the dramatically low oxygen consumption provides evidence of torpor, an energy-saving physiological state, which is very rare among passerine birds. The skin Tb of active flowerpeckers, just before nocturnal RMR measurements, averaged 41.1°C (their cloacal Tb was 41.2°C), while in resting non-torpid birds at night the skin Tb averaged 36.3°C. Our report is the first quantitative evidence of torpor in the family Dicaeidae.
The Asian Woollyneck Ciconia episcopus is a stork found throughout Asia whose international conservation status is currently being considered for reclassification from vulnerable to near-threatened. However, much of what is known about this species is fragmented across observational reports and small studies making a comprehensive assessment of population trends difficult. Here, we bring together all available published information to see what is known and what research questions still need answering in order to make reliable assessments of regional population trends and identify probable drivers of decline. Despite the species likely being extinct in the extremes of its former range and evidence of dramatic declines in Southeast Asia, Asian Woollyneck appears to be stable or increasing in India, Sri Lanka and Nepal. Observations of its preferred foraging and nesting habitats in South versus Southeast Asia show some obvious differences that may explain regional variations in population trends. In South Asia the bird is common in open grasslands and agricultural areas, while in Southeast Asia it is mostly observed in forested areas. Also, reports of the Asian Woollyneck nesting on cell phone towers is increasing in South Asia. However, because of a severe lack of reporting from Southeast Asia, it is unclear if or how these regional differences in population trends and habitat use are linked. Structured surveys and studies into the Asian Woollyneck foraging, nesting and movement ecology are urgently needed to understand the extent and drivers of decline in Southeast Asia. Therefore, researchers should focus future studies on population trends across the species' range, and aim to identify the local factors influencing recent changes in population growth. Without such knowledge, reassessment of its conservation status may be premature.
We report an exceptional case of Eurasian Eagle Owls Bubo bubo feeding on Stag Beetles Lucanus cervus in Germany, with the beetles making up 56.9% of all prey individuals. A review of literature and a comparison of data reveal that both the number and the biomass of the consumed beetles are typically too low to be of any nutritional importance with respect to the Eurasian Eagle Owl's broad food spectrum. Therefore, we conclude that Eurasian Eagle Owls merely opportunistically fed on this only seasonally available food source and that juvenile owls might prey on these beetles during their hunting exercises.
Although a number of infanticide cases have been recorded among birds, since the incidence of this behavior is, overall, low and difficult to confirm, the importance of infanticide in the cause analysis of breeding failure is likely to be underestimated. During the breeding season of March to August 2019, we observed two cases of non-kin infanticide in Oriental Magpie Robins Copsychus saularis in nest boxes. The first incident occurred during the absence of the nesting male during the brooding period and in the sole presence of the female; another male entered the nest box and continuously attacked and pecked all four eight-day-old nestlings in the nest until they died. A second incident occurred in the presence of both parents, but during the feeding interval; a male perpetrator entered the nest box and pecked and pushed the single three-day-old nestling out of the box. The parents continued to carry food to the nest and tried to feed their nestling even after the latter had been killed. The parents were observed behaving anxiously once they detected no sign of activity from their nestling. We speculated that these examples of non-kin infanticide by conspecific Oriental Magpie Robinmales could be attributed to competition for food resources or mates.
We documented an adult Lesser Cuckoo Cuculus poliocephalus killing nine-day-old Japanese Bush Warbler Cettia diphone nestlings by ejecting them from their nest. Among the available hypotheses concerning brood-parasitic birds destroying host nest contents, only the ‘farming hypothesis' helps to explain this case, although the attack did not force the warbler to immediately re-nesting because one nestling survived. Considering the long breeding season and frequent re-nesting habit of the Japanese Bush Warbler, as well as the delayed arrival of the Lesser Cuckoo into the breeding area, such predatory behavior seems to be effective in creating replacement clutches for future parasitism.
Renewable energy, including wind energy, remains one of the most effective options for controlling global warming. However, increasing wind turbine size (mainly blade size) implies expanding the blade swivel range (rotor sweep zone), and concerns have been raised about a possible increase in the number of bird collisions with the rotating blades. Conversely, an increase in turbine size, accompanied by a reduction in rotation speed might reduce the avian collision risk. The change in the number of collisions with increasing wind turbine size was analyzed using simple collision risk models. The results showed that with an increase in the length of the wind turbine blade, although the number of collisions per turbine increased monotonically, the number of collisions per megawatt generated decreased as a hyperbolic function. These models involved some assumptions for simplicity; therefore, their validity requires testing in wind-power replacement projects.
We sampled 70 urban ponds (0.001 to >1 ha) in Rome, Italy, to obtain richness and abundance data for wintering wild birds and domestic birds in relation to pond size. The aim was to test the hypothesis that the species-area relationship differs between wild and domestic birds, with the presence of the latter linked with anthropogenic factors, not pond area. We detected eight domesticated avian taxa and 19 wild species at 26 sites. Whereas there was a significant relationship between the number of wild bird species and pond area, the diversity of domestic taxa appeared not to be correlated with area (power function; Levenberg-Marquardt approach). Species-area relationships showed a lower variance in domestic taxa when compared with wild species. As smaller ponds in urban landscapes can host a higher number of domestic taxa than wild species, there may be implications both for increasing risk of disease transmission and for biodiversity perception among urban citizens.