Habitat associations of Yellow Wagtails Motacilla flava flavissima on lowland wet grassland

In common with many other previously widespread British birds, Yellow Wagtail Motacilla flava flavissima populations have declined substantially in the UK in recent decades. Recent national data suggest particular problems in grassland. We investigated how habitat management in a grassland area of East Anglia, England, influenced the habitat selection of this species. Breeding territories were associated with fields previously subject to prolonged winter floods and which contained shallow-edged ponds or wet ditches during summer. Territories were also associated with fields with short, sparse swards and high proportions of bare earth within the sward, and these features were themselves associated with previous winter flooding. However, nests were associated with taller swards than were random points within the same field, suggesting that Yellow Wagtails would benefit from within-field heterogeneity of sward height to provide both nesting and foraging habitat. We discuss how grazing, cutting and water-level management regimes could be used to promote optimal sward structure for Yellow Wagtails.     

Mid-season shifts in the habitat associations of Yellow Wagtails Motacilla flava breeding in arable farmland

Declines in habitat quality through the breeding season within a bird's home-range can limit overall productivity. In environments where multiple breeding opportunities arise during the course of a season, these effects can be buffered by a shift to different breeding sites or habitats. We studied the distribution and habitat associations of a crop-nesting farmland bird, the Yellow Wagtail Motacilla flava , across an arable-dominated farming region in eastern England using both field-scale territory mapping and large-scale transect surveys. Surveys were repeated at monthly intervals to measure changes in both distribution and habitat use during the course of the season. The distribution of breeding birds changed markedly at both regional and field-scales, coinciding with a shift in crop preference. Initially, most territorial birds were recorded in autumn-sown cereal fields, but this crop was subsequently abandoned in favour of potato crops, which were more patchily distributed. Other habitat features influencing Yellow Wagtail distribution included local crop diversity, hedgerow presence and soil type, with organic soils supporting higher abundance than alluvial clays or silts. The mid-season switch in habitat associations might allow individuals to maximize the number of breeding attempts made in a single year by using multiple habitats sequentially. The use of multiple habitats could influence population regulation by buffering the effects of local within-season declines in habitat suitability. Seasonal habitat switching may be more prevalent than is currently recognized in seasonal environments.     

The demography of Yellow Wagtails Motacilla flava on abandoned fields in northern European Russia

Capsule Apparent survival rates of Yellow Wagtails breeding in abandoned fields in Russia are determined by previous breeding success.

Aims To examine apparent survival and its link to previous breeding success in Yellow Wagtails breeding in abandoned fields in the Vologda region, northern European Russia.

Methods We ringed and measured apparent survival of Yellow Wagtails at two abandoned agricultural sites over eight years (2005–2012). We modelled the impact of age, nest stage, and time of season on daily nest survival rates.

Results Predation was the main cause of nest failure. Nest daily survival rate was highest at the beginning of the breeding season. Overall nest survival probability was 0.40?±?0.02. Adult apparent survival after successful breeding was 0.42?±?0.06 and after unsuccessful breeding this was 0.13?±?0.06.

Conclusion Reproductive success can be regarded as the crucial demographic parameter of the local Yellow Wagtail population in northern European Russia. Apparent survival after successful breeding is significantly higher than after unsuccessful breeding, because unsuccessful breeders probably move to new breeding sites the following year. High adult survival may be particularly important to Yellow Wagtail population dynamics in the study region, because second breeding attempts are apparently unusual.     

Breeding ecology of Yellow Wagtails Motacilla flava in an arable landscape dominated by autumn-sown crops

Capsule Yellow Wagtails successfully raised two consecutive broods in landscapes dominated by autumn-sown crops and did not require spring crops or fallow plots for later nesting.

Aims To assess whether arable landscapes dominated by winter cropping provide habitats that allow Yellow Wagtails to raise two successful broods. To assess the utility of spring cultivated agri-environment fallow plots as a nesting and foraging habitat for Yellow Wagtails.

Methods Nesting success and foraging behaviour of Yellow Wagtails was monitored on lowland arable farmland dominated by winter cropping during two successive breeding seasons.

Results Yellow Wagtails successfully raised first and second broods mainly in winter cereals, with later nests being more successful. Some nests were initiated in bean fields where egg-stage failure rates were high, probably as a consequence of depredation. Fallow plots were not used for nesting but, along with other areas of sparse vegetation, were regularly used for foraging.

Conclusions Yellow Wagtails breeding at relatively low densities achieved high rates of reproductive success in a landscape dominated by winter cereals and with few spring-sown crops. This study suggests that spring-sown crops may not be necessary for Yellow Wagtails to rear two successful broods each summer within arable landscapes.     

Flight muscle hypertrophy and ecophysiological variation of Yellow wagtail Motacilla flava races at Lake Chad

During the few days before emigration to the Palaearctic, the weight of Yellow wagtails wintering in Africa doubles. Most of the increase is due to the deposition of fat, as is well known, but a part of it is shown to result from hypertrophy of the pectoral muscles. The same applies to other Palaearctic birds, four warblers and a hirundine, that winter in Africa.
Eleven subspecies of M. flava occur at Lake Chad in spring. The four black-headed ones have more restricted habitat requirements than some of the others; however, no differences in diet have been found. There is no evidence of hyperphagia and little of diet change when fattening. Broadly, the races that have farthest to migrate leave earliest, and their sexual recrudescence and fattening are early.
Yellow wagtails wintering at or passing through Lake Chad breed mainly in eastern Europe (from the Adriatic to the Gulf of Finland, between about 12° and 30°E). They probably migrate on a great circle route, and during the flight lose one gram of weight, mainly fat, per 200 km.     

Yellow Wagtail Motacilla flava migration from West Africa to Europe: pointers towards a conservation strategy for migrants on passage

The biology of one passerine migrant, the Yellow Wagtail Motacilla flava, is examined in order to identify factors which need to be considered when attempting to conserve migrants on passage. The distribution of Yellow Wagtails in West Africa, prior to northward (spring) migration, is affected by food supplies and by different racial and sexual responses to environmental factors. Consequently, each breeding population relies on a wide range of sites, but those occupied towards the end of the dry season and ones used as stepping-off points for migration may be particularly vital.
Energetic considerations point towards a non-stop trans-Saharan flight being used rather than a series of short flights with resting stops in the desert. However, adverse conditions during migration could make stop-overs unavoidable. The most direct routes between wintering and breeding areas are preferred, and the initial desert crossing is accomplished at a faster pace than later stages of the journey.
Yellow Wagtails emigrate from West Africa in a sequence related to the onset of spring on their breeding sites, rather than in response to rainfall in Africa: moult, fattening and emigration are probably endogenously controlled. However, competition from African resident birds may also be an important factor affecting the timing of migration.
Races breeding in southern Europe are most likely to be adversely affected by degradation of the Sahel. Empirical evidence suggests that conditions on the wintering grounds are more likely to regulate population size than conditions experienced on migration, but more detailed studies are needed in Africa before sound conservation strategies can be designed.     

Breeding season, courtship behaviour, and territoriality of White and Japanese Wagtails Motacilla alba and M. grandis

The breeding ecology of White and Japanese Wagtails, Motacilla alba and M. grandis , was studied along a river in central Japan. The home ranges of the two species greatly overlapped along the river, but no interbreeding occurred. M. grandis spent more time on the river than M. alba and defended territories there. M. alba used the river as part of the entire home range, and did not defend the river areas as territories. Singing activity and breeding started earlier in M. grandis than in M. alba. The early breeding of M. grandis was related to the lack of moulting in spring, less necessity for pair formation due to the existence of pairs in the winter, and the greater dependency on larval than on adult insects. Songs were very different between the two species. The bowing display that preceded the pre-copulation display was found only in M. alba. During the pre-copulation display, male M. grandis lifted both wings above the horizontal while male M. alba drooped both wings. The pre-copulation display of M. grandis was similar to that of Large Pied Wagtails M. maderaspatensis in India, suggesting a closer relationship of the two species than to M. alba.     

Yellow wagtail Motacilla flava Linnaeus, 1758 (Passeriformes, Motacillidae, Motacillinae), in the Middle Volga Region: Geographical distribution, nesting biotopes, and numbers

A critical assessment of the literature data on the yellow wagtail Motacilla flava Linnaeus, 1758 (Passeriformes, Motacillidae, Motacillinae), at the turn of the 19th–20th centuries is carried out, assessment of its current numbers is given, and limiting factors and patterns of the species distribution on the study area of the European part of Russia, including the Middle Volga Region, are identified.     

Breeding density of Dippers Cinclus cinclus' Grey Wagtails Motacilla cinerea and Common Sandpipers Actitis hypoleucos in relation to the acidity of streams in south-west Scotland

The distribution of breeding pairs of Dippers Cinclus cinclus , Grey Wagtails Motacilla cinerea and Common Sandpipers Actitis hypoleucos was assessed along 18 streams in south-west Scotland during summer 1987, and the lengths of territories, occupied by 5 5 breeding pairs of Dippers, were measured. In each stream the water chemistry, physical structure (e.g. gradient, altitude, nature of bankside vegetation) and density of aquatic invertebrates was determined. The density of breeding pairs of dippers was significantly lower along streams of low pH (high acidity) and steep gradients, and territories were significantly longer at these sites compared with those of higher pH. Many of the invertebrate families that are important prey for Dippers were scarce at sites of low pH, particularly caddisfly larvae (Trichoptera) and mayfly nymphs (Ephemeroptera). The low numbers and large territories of breeding pairs of Dippers on acidic streams may be due to reduced density and diversity of macroinvertebrate prey. Stream pH was not an important correlate of the distribution or density of Grey Wagtails or Common Sandpipers. It is suggested that the lack of any similar effect of pH on these other two species compared with Dippers is attributable to differences in their feeding ecology.     

Dynamics in the evolution of sexual traits: losses and gains,radiation and convergence in yellow wagtails (Motacilla flava)

We analyse patterns of genetic diversity and song complexity in the Palaearctic yellow wagtail (Motacilla flava), a highly polytypic species complex. Mitochondrial and nuclear DNA show that the complex is polyphyletic, despite parallel plumage variation in western and eastern clades. In the western clade there is genetic structure among southern subspecies, haplotype diversity decreases with latitude, and northern subspecies show evidence of bottlenecking and rapid expansions, as expected from isolation in glacial refugia followed by postglacial colonization. However, northern subspecies, which have more divergent male plumages, lack genetic structure and sing simpler songs. Loss of song complexity and evolution of plumage in founder populations are consistent with the Kaneshiro model, which posits that variation among species is a consequence of founder-induced shifts in female preference leading to loss of ancestral male sexual traits. Our results suggest possible postglacial founder-effect mechanisms for the morhological diversification of the yellow wagtail complex.     

Ecology of yellow wagtail (Motacilla flava L.) in the forest tundra of Western Siberia and factors limiting its northward rage expansion

Based on the long-term studies of the ecology of yellow wagtail in the Lower Ob region and the experimental results, factors determining the penetration of this species into the tundra of the Yamal Peninsula have been analyzed.     

Allogrooming in cattle: Relationships between social preferences,feeding displacements and social dominance

The aim of this study was to describe the allogrooming behaviour of group-housed lactating cows (Bos taurus) as it relates to social dominance, friendship, parity and level of feeding competition. We measured the socio-negative (displacements at the feeder and in the lying stalls) and socio-positive interactions (allogrooming and preferential spatial associations) in six groups of eight dairy cows. This experimental model has been shown to be useful in investigating the effects of high social pressure in groups of cattle. The level of social competition was manipulated by halving the access to the feeder. Allogrooming was observed mostly at the feeder after fresh feed delivery and during the night between 12 and 2 a.m. Dominance rank had no effect on the expression of allogrooming. When competition between animals increased, allogrooming declined, especially in low-ranking, primiparous animals. In addition to its role in coat hygiene and potential role in reducing tension between animals competing for feed, we conclude that allogrooming may be a behaviour reflecting friendship in cows, because it is correlated to preferential associations between partners at the feeder. We suggest that primiparous cows are more susceptible to suffer from a lack of hygiene or socio-positive relationships when submitted to high competitive pressure, especially when they are mixed with more experienced animals that could have better coping strategies in a high competition situation.     

Interactions between cattle and biting flies: effects on the feeding rate of tsetse

In Zimbabwe, studies were made of the effect of host behaviour on the feeding success of Glossina pallidipes Austen and G. morsitans morsitans Westwood (Diptera: Glossinidae) attracted to cattle of different age and sex. The mean feeding rates for male and female G. pallidipes attracted to oxen were 60% and 58%, respectively, compared to 33% and 53% for male and female G. m. morsitans. The feeding rate of G. pallidipes varied between oxen and was inversely correlated with a host's rate of defensive leg movements, which, in turn, was positively correlated with the density of Stomoxys spp. (Diptera: Muscidae) caught in the vicinity of the host. Tsetse were significantly less successful in feeding from young cattle. For G. pallidipes, the feeding rate on calves (<6 months) was 11%, whereas for male and female G. m. morsitans the rates were 12% and 20%, respectively. Significantly lower feeding rates were apparent for cattle aged up to 2 years, when the feeding rate for G. pallidipes (31%) was still significantly less than that on mature oxen (68%). Feeding rates for G. pallidipes on adult female cattle were lower than those on oxen (45% vs. 61%). The lower feeding rates in young animals were attributed to higher rates of defensive movements. The results suggest that higher rates of defensive activities by young cattle reduce the risk of them contracting trypanosomiasis.     

Commensal symbiosis between agglutinated polychaetes and sulfate‐reducing bacteria

Pendant bioconstructions occur within submerged caves in the Plemmirio Marine Protected Area in SE Sicily, Italy. These rigid structures, here termed biostalactites, were synsedimentarily lithified by clotted‐peloidal microbial carbonate that has a high bacterial lipid biomarker content with abundant compounds derived from sulfate‐reducing bacteria. The main framework builders are polychaete serpulid worms, mainly Protula with subordinate Semivermilia and Josephella. These polychaetes have lamellar and/or fibrillar wall structure. In contrast, small agglutinated terebellid tubes, which are a minor component of the biostalactites, are discontinuous and irregular with a peloidal micritic microfabric. The peloids, formed by bacterial sulfate reduction, appear to have been utilized by terebellids to construct tubes in an environment where other particulate sediment is scarce. We suggest that the bacteria obtained food from the worms in the form of fecal material and/or from the decaying tissue of surrounding organisms and that the worms obtained peloidal micrite with which to construct their tubes, either as grains and/or as tube encompassing biofilm. Peloidal worm tubes have rarely been reported in the recent but closely resemble examples in the geological record that extend back at least to the early Carboniferous. This suggests a long‐lived commensal relationship between some polychaete worms and heterotrophic, especially sulfate‐reducing, bacteria.     

AGHR polymorphism and its associations with carcass traits in Harrwoo cattle

The growth hormone receptor (GHR) is a membrane transmitter for the growth hormone signal transduction pathway that regulates various metabolic activities, including cell growth and expressions of cytokine genes. The presence or absence of a genetic polymorphism for the LINE-1 retroposon in the PI promoter, which specifically regulates theGHR gene expression in the liver, was screened by a novel detection method and examined for its relationships with carcass traits in Hanwoo cattle. Han woo cattle had taurine type LINE-1 present (alleleI) as well as incidine type LINE-1 absent (alleleA) promoter sequences. Three genotypes,I/I, I/A andA/A, showed frequencies of 49.1, 36.7 and 14.2%, respectively. The effects of allele A were significant on mean differences for final weight, eye muscle area, marbling score and fat color (p<0.05), but not for carcass weight, backfat thickness, final meat quality grade or meat color (p>0.05). Most 30-month old Hanwoo steers bearing the LINE-1 absent promoter had whiter fat color, heavier live weight and higher marbling score, reflecting intramuscular fat deposition inM. longissimus dorsi, compared to animals bearing a LINE-1 present promoter. This suggests that aGHR polymorphism could be a potential genetic marker for improving beef production of Hanwoo cattle.     

Network Analysis Highlights Complex Interactions between Pathogen,Host and Commensal Microbiota

Interactions between bacteria and their host represent a full continuum from pathogenicity to mutualism. From an evolutionary perspective, host-bacteria relationships are no longer considered a two-component system but rather a complex network. In this study, we focused on the relationship between brook charr (Salvelinus fontinalis) and bacterial communities developing on skin mucus. We hypothesized that stressful conditions such as those occurring in aquaculture production induce shifts in the bacterial community of healthy fish, thus allowing pathogens to cause infections. The results showed that fish skin mucus microbiota taxonomical structure is highly specific, its diversity being partly influenced by the surrounding water bacterial community. Two types of taxonomic co-variation patterns emerged across 121 contrasted communities’ samples: one encompassing four genera well known for their probiotic properties, the other harboring five genera mostly associated with pathogen species. The homeostasis of fish bacterial community was extensively disturbed by induction of physiological stress in that both: 1) the abundance of probiotic-like bacteria decreased after stress exposure; and 2) pathogenic bacteria increased following stress exposure. This study provides further insights regarding the role of mutualistic bacteria as a primary host protection barrier.