EISSN : 2053-7166
Published by: Springer Science and Business Media LLC (10.1186)
Total articles ≅ 268
Latest articles in this journal
Avian Research, Volume 12, pp 1-11; doi:10.1186/s40657-021-00272-7
Background Despite an increasing number of surveys and a growing interest in birdwatching, the population and distribution of Asian Dowitcher (Limnodromus semipalmatus), a species endemic to the East Asian–Australasian and Central Asian Flyways, remains poorly understood, and published information about the species is largely outdated. In boreal spring 2019, over 22,432 Asian Dowitchers were recorded in a coastal wetland at Lianyungang, Jiangsu Province, China, constituting 97.5% of its estimated global population. Methods In 2019 and 2020, we conducted field surveys at Lianyungang to determine the numbers of Asian Dowitchers using the area during both southward and northward migrations. We also assessed the distribution and abundance of Asian Dowitchers elsewhere along the China coast by searching literature and consulting expert opinion. Results The coastal wetlands of Lianyungang are the most important stopover site for Asian Dowitchers during both northward and southward migrations; they supported over 90% of the estimated global population during northward migration in two consecutive years (May 2019 and 2020). This area also supported at least 15.83% and 28.42% (or 30.74% and 53.51% using modelled estimates) of the global population during southward migration in 2019 and 2020 respectively. Coastal wetlands in the west and north of Bohai Bay also have been important stopover sites for the species since the 1990s. Although comprehensive, long-term monitoring data are lacking, available evidence suggests that the population of the species may have declined. Conclusions The high concentration of Asian Dowitchers at Lianyungang during migration means the species is highly susceptible to human disturbances and natural stochastic events. The coastal wetlands of Lianyungang should be protected and potentially qualify for inclusion in China’s forthcoming nomination for World Heritage listing of Migratory Bird Sanctuaries along the Coast of Yellow Sea-Bohai Gulf of China (Phase II) in 2023. Additional research is needed to understand Asian Dowitchers’ distribution and ecology, as well as why such a high proportion of their population rely on the Lianyungang coast.
Avian Research, Volume 12; doi:10.1186/s40657-021-00273-6
Background Parental investment by birds is limited by the habitat environment, and a male parent increases its effort to reproduce in birds that live in high-altitude areas. Methods A study of the reproductive behaviour of the Saxaul Sparrow (Passer ammodendri) and the Isabelline Shrike (Lanius isabellinus) was carried out at the Gansu An’xi Extremely Arid Desert National Nature Reserve in northwest China to determine the reproductive input of passerine species in desert habitats. Results In Saxaul Sparrows, compared to the female parent, the male parent exhibited a significantly higher frequency of nest-defense behaviour (chirping and warning) during nesting, hatching and feeding periods. In addition, in comparison to the female parent, the male parent exhibited almost equal frequencies of nesting and incubation but fed nestlings significantly more times. Similar to the male sparrows, the feeding rates of the male Isabelline Shrikes were significantly higher than those of the females. The hatching rate and fledging rate of the Saxaul Sparrow on average in this study were 81.99 and 91.92%, respectively, while those of the shrike were 69.00 and 96.53%, respectively. Conclusions These two different passerine species living in the same desert environment exhibited the same trend in their reproductive investments. Adapting to desert environments is a strategy that may have evolved in passerines where male parent birds put more effort than females into reproduction to ensure high reproductive output.
Avian Research, Volume 12, pp 1-8; doi:10.1186/s40657-021-00271-8
Background Philopatry rate is one of the main factors shaping population dynamics in colonial seabirds. Low rates of philopatry are linked to populations with high dispersal, while high rates are linked to populations with a very high spatial structure pattern (i.e., metapopulations). The Cantabrian Yellow-legged Gull (Larus michahellis) population is considered to be resident, with relatively low dispersal rates. Precise estimations of its philopatry rates are however still lacking. Here, we aimed to estimate philopatry rates in the main Yellow-legged Gull colonies of the province of Gipuzkoa, in the southeastern part of the Bay of Biscay. Methods We analysed 734 resightings, during the breeding season at the colonies of Getaria, Santa Clara and Ulia, relative to a total of 3245 individuals ringed at birth in these same colonies during a period of 13 years. These data were analysed using Multi-State Recapture models in MARK. Results After controlling survival and resighting probability, the average dispersal rate among colonies was 4% (± SD = 2%) when individuals are immature, decreasing to 1 ± 1%) for adult breeding gulls (i.e., philopatry rate was 99%). Annual survival rates were assessed to be 0.27 ± 0.02 for birds in their first year of life and 0.87 ± 0.01 for older individuals. The probability of observing immature birds in the colonies was 0.08 ± 0.01, as compared to 0.21 ± 0.02 in adult birds. Conclusions We obtained evidence of extremely high local philopatry rates, clearly within the upper limit found in gulls. A high philopatry favour a speciation in these species who are vulnerable to obtain the main food source (landfills and fishing discard) which are transforming under new ecological process.
Avian Research, Volume 12, pp 1-10; doi:10.1186/s40657-021-00270-9
Background Communal roosting is a common avian social behaviour, which potentially provides foraging benefits, predation avoidance or thermoregulation in birds. To identify the crucial environmental factors associated with roost site selection, most studies have focused on the comparison of physical characteristics between roosts and non-roosts. However, the differences among roosts have usually been neglected and the causes of roost switching have seldom been investigated. Methods To explore the variations among roost sites and assess the most influential environmental factors related to seasonal roost switching, we conducted a 105-day observation on an introduced population of critically endangered Yellow-crested Cockatoo (Cacatua sulphurea) in an urban environment in Hong Kong from 2014 to 2016. We identified seven roost sites that were occupied in different seasons and then measured their microhabitat characteristics in terms of land use types, human disturbance and microclimate temperature. To quantify these differences, we used Pearson’s chi-squared test, partial least squares determinant analysis (PLS-DA) and one-way repeated measures ANOVA, respectively. Results Our results distinguished roost sites occupied in three seasons, i.e. spring, summer and winter roosts, using several microhabitat characteristics. The land use types were significantly associated with roosts, where spring roosts were usually located in tree-dominated areas, which are the major feeding grounds. The discriminant analysis on human disturbance variables indicated that summer roosts were positively associated with night illumination. The microhabitat temperatures of winter roosts were significantly higher than those of most other roosts on cold nights. Conclusions The results highlighted significant variations among roosts, and seasonal roost switching was likely driven by specific microhabitat characteristics of each roost site, such as microclimate. It also helps us understand the behavioural adaptation of birds to urban environments.
Avian Research, Volume 12, pp 1-13; doi:10.1186/s40657-021-00266-5
Background Bird nests are an important part of avian ecology. They are a powerful tool for studying not only the birds that built them, but a wide array of topics ranging from parasitology, urbanisation and climate change to evolution. Despite this, bird nests tend to be underrepresented in natural history collections, a problem that should be redressed through renewed focus by collecting institutions. Methods Here we outline the history and current best practice collection and curatorial methods for the nest collection of the Australian National Wildlife Collection (ANWC). We also describe an experiment conducted on nests in the ANWC using ultrasonic humidification to restore the shape of nests damaged by inappropriate storage. Results The experiment showed that damaged nests can be successfully reshaped to close to their original dimensions. Indeed, restored nests were significantly closer to their original shape than they were prior to restoration. Thus, even nests damaged by years of neglect may be fully incorporated into active research collections. Best practice techniques include extensive note taking and photography in the field, subsampling of nests that cannot or should not be collected, appropriate field storage, metadata management, and prompt treatment upon arrival at the collection facility. Conclusions Renewed focus on nest collections should include appropriate care and restoration of current collections, as well as expansion to redress past underrepresentation. This could include collaboration with researchers studying or monitoring avian nesting ecology, and nest collection after use in bird species that rebuild anew each nesting attempt. Modern expansion of museum nest collections will allow researchers and natural history collections to fully realise the scientific potential of these complex and beautiful specimens.
Avian Research, Volume 12, pp 1-8; doi:10.1186/s40657-021-00264-7
Background Interspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) in temporal, spatial and trophic dimensions. Methods Field study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection. Results We found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), whereas Cattle Egret foraging sites were characterized by grasslands (44.44%), paddy fields (33.33%) and river banks (22.22%). Little Egrets consumed more fishes (65.66%) and Odonata larvae (13.69%) than Cattle Egrets, while Cattle Egrets were found feeding mainly on Coleoptera (29.69%) and Orthoptera (23.29%). Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets. Conclusions Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. In two coexisting egret species, niche partitioning is multidimensional, such that the two coexistent species occupy differing ecological space based on all three temporal, spatial and trophic niche dimensions.
Avian Research, Volume 12, pp 1-4; doi:10.1186/s40657-021-00269-2
Birds underlie a predation-starvation risk, and foraging should show a diurnal/circadian pattern. Camera traps were used to study visitation patterns and discovery of a novel food source in woodland birds in SW Germany. A total of 18 species occurred at feeders with nine of them being exploratory species. Great Tits (Parus major) discovered novel food sources first in most instances, and first discoveries occurred on average at 10:38, while it took 97 h for the first detection of the food source. Population size was correlated with discovery. The study supports the predation-starvation risk hypothesis with discovery of food sources in the morning.
Avian Research, Volume 12, pp 1-8; doi:10.1186/s40657-021-00268-3
Background The extent to which pairs remain together during the annual cycle is a key question in the behavioural ecology of migratory birds. While a few species migrate and winter as family units, for most the extent to which breeding partners associate in the non-breeding season is unknown. The Arctic Tern (Sterna paradisaea) has one of the longest migrations of any species, and the aim of this study was to establish whether or not partners remain together after breeding. Methods Leg-mounted geolocators were fitted to breeding pairs of Arctic Terns nesting on the Farne Islands, Northumberland, UK. The devices were recovered for analysis the following year. Results Analysis of data for the six pairs which returned the following year showed that partners departed from the colony at different times after breeding and migrated independently to different Antarctic regions. Partners also departed from the Antarctic and turned to the breeding colony independently. One third of the pairs divorced on return. Conclusions For long-distance migrants reliant on unpredictable foraging opportunities, it may not be viable to remain as pairs away from the breeding colony. Synchrony in arrival times at the breeding colony may maximise the chance of retaining a familiar partner, but could be affected by environmental factors in wintering areas or along migration routes.
Avian Research, Volume 12, pp 1-10; doi:10.1186/s40657-021-00267-4
Background The European Kingfisher (Alcedo atthis) is a small plunge-diving bird, today considered a species of conservation concern in Europe given its rapid population decline observed across the continent. We implemented a pilot study aimed at providing first data allowing to: (1) assess home range features of the European Kingfisher for populations with unevenly distributed feeding habitats; (2) define conservation implications for habitats exploited by such populations; and (3) evaluate possibilities for developing GPS tracking schemes dedicated to home range studies for this species that could be possibly applied to other small plunge-diving birds. Methods In 2018 and 2019, we equipped 16 breeding European Kingfishers sampled within the marshes of the Gironde Estuary (France), with miniaturized and waterproof GPS archival tags deployed with leg-loop harnesses (total equipment mass = 1.4 g; average bird mass = 40.18 ± 1.12 g). Results On average, we collected 35.31 ± 6.66 locations usable for analyses, without a significant effect on bird body condition (n = 13 tags retrieved). Data analyses highlighted rather limited home ranges exploited by birds (average = 2.50 ± 0.55 ha), composed on average by 2.78 ± 0.40 location nuclei. Our results also underscore: (1) a rather important home range fragmentation index (0.36 ± 0.08); and (2) the use by birds of different types of small wetlands (wet ditches, small ponds or small waterholes), often exploited in addition to habitats encompassing nest locations. Conclusions Our study reveals interesting GPS tracking possibilities for small plunge-diving birds such as the European Kingfisher. For this species, today classified as vulnerable in Europe, our results underline the importance of developing conservation and ecological restoration policies for wetland networks that would integrate small wetlands particularly sensitive to global change.
Avian Research, Volume 12, pp 1-10; doi:10.1186/s40657-021-00265-6
Background In this study we examined the habitat preferences of three diurnal raptors in relation to human access. We aimed to identify the selection of breeding habitat by the Golden Eagle (Aquila chrysaetos), the Long-legged Buzzard (Buteo rufinus), and the Peregrine Falcon (Falco peregrinus) in response to site accessibility by humans, and in turn, the response of these species to human presence. Methods Data about the nest locations were collected. Analyses and maps were created using ArcGIS. The “least cost path” was defined using the Cost Path tool. Results The lowest values of the Cost Path were established for Long-legged Buzzard and the highest values were estimated for Golden Eagle. Intermediate Cost Path values for Peregrine Falcon were found. Conclusions The Long-legged Buzzard could be considered as the most tolerant to human presence in its breeding territories. The Golden Eagle have the lowest degree of tolerance and the Peregrine Falcon is ranked in an intermediate position compared to the other two species, but closer to Golden Eagle.