Rails (family Rallidae) are adapted to wetland habitats, nesting in emergent vegetation where flooding is one of the main factors that contributes to nesting failure rates. We conducted an experiment to test the capacity of water rail and Japanese quail embryos to survive flooding. During the experiment, 52 water rail and 60 quail eggs were divided into three groups. One control group was artificially incubated in standard conditions and the other two groups were submerged during artificial incubation for 2 hours and 3 hours, respectively, in the third week of the incubation period in water at 21 °C. A total of 88.2% of water rail eggs hatched in the control group, 83.3% in the 2 h flooded group and 29.4% in the 3 h flooded group. For the quail eggs, 75% hatched in the control group, 10% in the 2 h flooded group and 5% in the 3 h flooded group. Water rail embryos were five times more resistant to 2 h flooding conditions, and approximately twice as resistant to a 3 h immersion compared to quail embryos. The elevated survival rate of water rail embryos may be related to their capacity to enter torpor.

Although rapid growth in the extent of urbanized habitats across the globe represents a major threat to biodiversity, there is growing evidence that urban ecosystems can represent suitable habitats for many taxa, including birds. Exploring aspects of bird ecology across the urban-rural gradient, including determinants of habitat associations, are crucial to understanding responses to urbanisation. Here, we examined factors affecting nest-site selection of Eurasian magpies across an urban-rural gradient, contrasting urban and non-urban habitats. The presence and density of Eurasian magpie nests was positively associated with the proportion of green urban areas, and negatively with forests, arable land and buildings, despite habitat associations differing across the urban-rural gradient. We also found a negative relationship between nest height and distance from city edge. The highest nests were found in city centre residential areas, whereas the lowest nests were in the new residential areas. We conclude that Eurasian magpies can successfully exploit urban environments, partially due to adaptation of their nesting behaviour. In particular, they construct their nests higher in urban areas to avoid the negative impacts of human disturbance and predation.

Hosts of obligate avian brood parasites can reduce the costs of raising parasitic offspring by rejecting foreign eggs from their nests. Rejecter hosts use various visual and tactile cues to discriminate between own and foreign eggs. The blunt pole hypothesis specifically states that avian-perceivable visual information at and around the broader pole of the eggshell contains more salient recognition cues than does the sharp pole of the same egg. The directional prediction is, therefore, that eggs painted non-mimetically on their blunt pole should more likely be rejected relative to those similarly painted on their sharp pole. This hypothesis had been experimentally tested and its predictions supported solely in mimetic avian host-parasite systems, with hosts producing denser and more variable eggshell maculation patterns at the blunt pole, and in one species with immaculate eggs but still with distinctly discernible blunt-pole specific colouration. Here we aimed to expand upon these previous works and assessed whether the blunt pole of model eggs contains more salient egg rejection cues, relative to the sharp pole, for the American robin (Turdus migratorius), a robust rejecter of non-mimetic brown-headed cowbird (Molothrus ater) eggs. In this system host eggs are uniformly immaculate whereas the brood parasitic shell is maculated. We painted model cowbird-sized eggs on either the blunt or the sharp half to mimic the immaculate robin egg colours and the other half to resemble non-mimetic egg colours and patterns. There was no statistical support for the predicted outcomes of the blunt pole hypothesis in our trials as rejection rates were similar regardless of whether eggs were painted with non-mimetic colours on the blunt or sharp poles. Future work should test the role of asymmetrical signalling content for anti-parasitic rejection of eggs in additional host species, especially those with both immaculate own and mimetic parasitic eggs.

This study investigated the browning plasticity of white adipose tissue (WAT) in Tupaia belangeri during cold acclimation and rewarming in order to demonstrate the adaptation mechanism of tree shrews to environmental change. The experimental group was transferred to a cold temperature, 5 ± 1 °C, acclimated for 28 d, and then returned to 25 ± 1 °C for 28 d, while the control group was maintained at the acclimation temperature, 25 ± 1 °C, for 56 d. Body mass, food intake, resting metabolic rate (RMR), WAT mass, morphology and related gene expression in male T. belangeri were measured. The results showed that body mass, food intake and RMR increased significantly under cold acclimation. There was also a significant increase in WAT mass and expression of peroxisome proliferation receptor α (PPARα), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), cyclooxygenaseII (COXII), bone morphogenetic protein 7 (BMP7) and the PR domain containing 16 (PRDM16), all of which decreased to control levels after rewarming. Further, WAT cells showed more multilocule adipocytes during cold acclimation, which returned to control levels after rewarming. These results suggest that browning may appear in the WAT of T. belangeri during cold acclimation. The return to control levels of WAT cell characteristics and expression of the genes involved in WAT browning after rewarming demonstrates strong browning plasticity.

The common cuckoo Cuculus canorus is an obligate brood parasite that lays its eggs in the nests of small passerines. It has long been hypothesized that cuckoo eggs should be structurally stronger than host eggs or those of non-parasitic cuckoos to reduce chances of breakage during laying, to prevent accidental damage during incubation and/or to hinder their rejection through puncture ejection by the host. Therefore, we analysed selected characteristics of a sample of freshly laid eggs of the common cuckoo with two of its major hosts, the reed warbler Acrocephalus scirpaceus and great reed warbler Acrocephalus arundinaceus, and a sample of species with known puncture resistant eggs. We found that in puncture resistance tests cuckoo eggs tolerated on average 231 g. The cuckoo eggs were 3.3 and 2.5 times stronger than those of the reed warbler and great reed warbler, respectively. Greater shell thickness can explain only 17% of the total extra strength of the cuckoo eggs (125.97 g). When we controlled for the confounding effects of egg size (using a sample of eggs of normal strength from bird species of varying size), the common cuckoo eggs were 2.2 times stronger than expected for their size. Our results are consistent with the hypothesis that cuckoo eggs are structurally stronger and this trait probably represents an adaptation for a brood parasitic life style.

In this study, we provide a descriptive assessment of how chemical and hydro-morphological stressors have affected the fish community along one of the most impacted rivers in Central Europe. In addition to the toxicity of combined pollutants (expressed in toxic units), a range of hydro-morphological characteristics were measured to assess which stressors have had an impact. No longitudinal spatial trend was observed in fish assemblage characteristics as individual sites were affected by different stressors. Instead, five largely artificial assemblage “zones” were identified corresponding to different combinations of stressors. Water quality (principally dissolved O₂) and hydromorphology were the main drivers affecting fish presence and density, with self-purification processes, restocking from tributaries and geomorphology promoting fish survival and/or recovery, despite increasing toxic pressure downstream. Our results suggest that a) toxic units alone are insufficient to establish causative factors in fish community loss as they do not take account of hydro-morphological stressors, many of which interact with and/or mask each other, and b) that a single WFD monitoring site in such heavily impacted rivers is insufficient to assess ecological status; rather, the ecological status of specific “zones” (identified based on fish assemblage structure, habitat and water quality) should be assessed, with the ultimate aim of merging the zones and returning the river to a single functioning longitudinal ecosystem, accepting that this is unlikely to resemble the natural pre-industrial status of the river.

Migration and hibernation are survival strategies that require physiological preparation using fattening. Bats employ both strategies in times of resource shortages. However, because males and females vary seasonally in their reproductive physiological needs, they may employ different fattening patterns. Whilst fattening, migration and hibernation are common in temperate bats, little is known about subtropical migratory insectivores. This study investigated seasonal variation in body mass of the regionally migrating Natal long-fingered bat Miniopterus natalensis to determine if males and females show fattening in preparation for migration/hibernation. Seasonal change best explained the variation observed in overall body mass, whilst sex and forearm length explained the variation to a lesser extent. Body mass between males and females differed significantly by reproductive category among the four seasons. Forearm length was a significant predictor of the body mass of males. Scrotal males had a higher body mass in summer compared to autumn. This pattern of mass gain was not observed in non-scrotal males. The summer body mass of nonpregnant and post-lactating females was not significantly higher than the autumn body mass of nonpregnant females, which did not support the hypothesis that females would exhibit fattening during summer before migration. Results suggest that males and females employ different mass-gain strategies related to reproductive investment rather than fattening preparation for migration or hibernation.

This article analyses the factors underlying the spatial distribution of a rodent community in the arid conditions of the Caspian Lowland. Based on a habitat selection model, we hypothesized that sympatric species would occupy and utilize species-specific environmental habitats and resources in common spaces and that niche overlap between species would be low. Thirteen environmental parameters were chosen for study. Nine parameters significantly discriminated interspecies differences (Meriones meridianus occurred in dry microhabitats, Meriones tamariscinus occurred in wetter microhabitats, and Apodemus witherbyi and Cricetulus migratorius showed eurybiotic spatial patterns). Mus musculus was predominantly found in wet environmental conditions. Thus, A. witherbyi and C. migratorius were characterized by the greatest range of spatial niches in the community, and M. musculus was characterized by the narrowest range of spatial niches. Pairwise comparisons of rodent spatial niches revealed low overlap values.

The morphology and morphometry of the micropyle of two Korean rice fishes, Oryzias latipes and O. sinensis, were investigated by light microscopy and scanning electron microscopy. Obtained from adult gravid females during the spawning season, the full-grown eggs of each species have a single micropyle at the animal pole. For the two species, the micropyles are similar in appearance, but there exist some differences in detail. The egg is larger in O. latipes than in O. sinensis (1,123.3-1,465.5 µm vs. 823.1-1,152.1 µm in diameter), and the outer diameter of a single micropyle for O. latipes is nearly two times larger than that of O. sinensis (18.5-22.4 µm vs. 10.0-12.5 µm). The micropylar diameter to egg diameter ratio (1.6 ± 0.1% vs. 1.0 ± 0.1%) is also larger in O. latipes than O. sinensis. In regard to micropyle structure, the two showed distinguishing characteristics: O. latipes has a funnel-shaped micropyle consisting of two regions, an outer gradual pit and an inner narrow canal, while O. sinensis has a conical-shaped micropyle having only a deep narrow canal. Consequently, these differences in micropylar structure between the two Korean rice-fishes may be considered as a useful taxonomic characteristic in closely related taxa and seem to be structural adaptations to shape and control entry velocity of spermatozoa into the micropyle.

The Ionian Island of Corfu is rich in both species and habitats, but is also under pressure from heavy tourism, substantial water abstraction, and increased development, all of which have caused both loss and fragmentation of habitats. In addition, invasive alien species (IAS) constitute a global problem and may cause substantial problems for indigenous wildlife, especially on islands. To be able to successfully control IAS it is important to identify them, report their status, and raise awareness as early as possible. Here we present the status of ten alien species reported from Corfu, four of which are considered as invasive, the coypu (Myocastor coypus), the raccoon (Procyon lotor), the Siberian chipmunk (Tamias sibiricus), and the American pond slider (Trachemys scripta). Measures required as outlined by the EU Working Group on Invasive Alien Species are briefly discussed.