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In recent decades, numerous studies have examined factors affecting risk of host nest parasitism in well-known avian host-parasite systems; however, little attention has been paid to the role of host nest availability. In accordance with other studies, we found that nest visibility, reed density and timing of breeding predicted brood parasitism of Great Reed Warblers Acrocephalus arundinaceus by the Common Cuckoo Cuculus canorus. More interestingly, hosts had a greater chance of escaping brood parasitism if nesting was synchronized. Cuckoo nest searching was governed primarily by nest visibility at high host-nest density. However, even well-concealed nests were likely to be parasitized during periods when just a few hosts were laying eggs, suggesting that Cuckoos adjust their nest-searching strategy in relation to the availability of host nests. Our results demonstrate that host vulnerability to brood parasitism varies temporally and that Cuckoo females are able to optimize their nest-searching strategy. Moreover, our study indicated that Cuckoos always manage to find at least some nests to parasitize. Thus, in this case, the co-evolutionary arms race should take place mainly in the form of parasitic egg rejection rather than via frontline pre-parasitism defence. [ABSTRACT FROM AUTHOR]

Despite recent advances in technology, it remains difficult to connect breeding and non-breeding areas of populations of migratory organisms due to the challenges of year-round tracking. Here, we used the Eurasian reed warbler Acrocephalus scirpaceus, a passerine with a pronounced migratory divide to demonstrate the promise of integrating several sources of information within the Bayesian modelling framework for the study of migratory connectivity. To this end, we combined data from stable hydrogen isotope ratios (δ2H) of feathers, ring recoveries, and the geographic delineation of sub-populations on either side of the migratory divide. Feather δ2H measurements from local juvenile birds sampled across the breeding range tightly correlated with amount-weighted mean annual precipitation δ2H values predicted for the natal sites. Predicted natal origins of birds intercepted en route in the Mediterranean region largely differed among the five stopover sites. Thanks to the different migratory pathways used by different breeding populations and the existence of a migratory divide, we were able to effectively narrow the assigned regions of origin. Our results show that spatial resolution of likelihood-based assignments of geographic origins based on δ2H measurements may improve significantly when prior probabilities derived from population-specific migratory directions are included. Integrating information from stable isotopes, ring recoveries, geolocators and other sources within the Bayesian modelling framework will provide an extremely useful toolbox for the study of animal movements in the future. [ABSTRACT FROM AUTHOR]

Infections caused by the intestinal ciliate Neobalantidium coli are asymptomatic in most hosts. In humans and captive African great apes clinical infections occasionally occur, manifested mainly by dysentery; however, factors responsible for development of clinical balantidiasis have not been fully clarified. We studied the effect of dietary starch on the intensities of infection by N. coli in two groups of captive chimpanzees. Adult chimpanzees infected by N. coli from the Hodonín Zoo and from the Brno Zoo, Czech Republic, were fed with a high starch diet (HSD) (average 14.7% of starch) for 14 days, followed by a five-day transition period and subsequently with a period of low starch diet (LoSD) (average 0.1% of starch) for another 14 days. We collected fecal samples during the last seven days of HSD and LoSD and fixed them in 10% formalin. We quantified trophozoites of N. coli using the FLOTAC method. The numbers of N. coli trophozoites were higher during the HSD (mean ± SD: 49.0±134.7) than during the LoSD (3.5±6.8). A generalized linear mixed-effects model revealed significantly lower numbers of the N. coli trophozoites in the feces during the LoSD period in comparison to the HSD period (treatment contrast LoSD vs. HSD: 2.7±0.06 (SE), z = 47.7; p<<0.001). We conclude that our data provide a first indication that starch-rich diet might be responsible for high intensities of infection of N. coli in captive individuals and might predispose them for clinically manifested balantidiasis. We discuss the potential nutritional modifications to host diets that can be implemented in part to control N. coli infections. [ABSTRACT FROM AUTHOR]

The study of agriculture continues to become less popular in most developed countries, including Canada and the Czech Republic. The analysis in this paper provides some interesting findings about activities of agricultural universities to increase enrolment into their programmes. While the study is focused on Canada, it is possible to draw implications also for the Czech Republic as many of the characteristics pertaining to the education and agricultural sectors are similar. Enrolment into educational programs in agriculture in North America has been steadily declining in recent years. While the overall share of agriculture on the national gross domestic product has also been falling, the need for qualified people in agriculture is still important as the shift to sustainable agriculture appears to be one of the key priorities of governments in the US and Canada. One of the ways to stimulate the interest of prospective students in agricultural studies is to diversify the programmes by offering more major options. It is important to study the motivation and other stimuli for the choice of major in order to adapt the educational programmes to attract more students. In the paper, factors influencing the choice of major are studied by analysing survey data from the only agricultural college in Atlantic Canada. The results show significant differences in the socioeconomic background among the prospective students, based on the choice of major. For example, students interested in the social sciences consider choices of major much more than students in the biophysical fields. Based on the findings from the analysis, several recommendations are made. It is suggested, for example, that for students interested in the biophysical sciences, sport plays an important role and thus, an appropriate promotional campaign about recreation and sport facilities of post-secondary agricultural educational institutions should be conducted. Analysis in this paper may interest many educational institutions in agriculture as a guide on how to deal with existing or potential decline in enrolment by diversifying their major portfolio using appropriate promotional campaigns. [ABSTRACT FROM AUTHOR]

The prevalent, and so far most explored, host defense against brood parasitism is egg discrimination. Not only do the hosts differ markedly in their propensity to reject parasitic eggs but rejecters even vary in their egg rejection times. The focus of the present study was to investigate factors potentially responsible for high variation in timing of host egg rejection. As a model species, we chose the great reed warbler Acrocephalus arundinaceus, a cuckoo Cuculus canorus host, with female-restricted egg ejection behavior. We presented a cuckoo dummy near host nests and experimentally parasitized the clutches with a nonmimetic egg. Immediately afterward, we continuously video recorded host behavior to determine egg ejection times accurately. We fitted a regression tree model with the timing of egg ejection as a dependent variable and female-related characteristics (body condition, eggshell coloration, and behavior) as explanatory variables. Only female behavior toward the foreign egg proved to have a significant effect on the timing of egg ejection. Females devoting more time to clutch inspection ejected the egg significantly more quickly than females inspecting their experimentally parasitized clutches only briefly. We discuss our results in the context of known intra- and interspecific differences in host response times toward alien eggs and cognitive mechanisms involved in host egg discrimination processes. [ABSTRACT FROM PUBLISHER]

The article presents a study which investigated the intraspecific variation in the wing shape and genetic variation which could affect the aerodynamics and flight performance of Reed Warblers in Croatia. It states that the differences in the wing morphology and genotypes between coastal and inland breeding populations may affect migratory routes and wintering areas of the birds. Corresponding genetic differentiation between the two populations at neutral microsatellite loci and allele frequencies are explained.

Hosts of the common cuckoo (Cuculus canorus) may foster a foreign chick instead of raising their own progeny, which incurs a significant cost to their fitness. Chick recognition or discrimination is, however, rare in cuckoo hosts and has been investigated exclusively in relation to nestling provisioning. Here we test for the first time whether hosts differ in the willingness of risk-taking when they care for own or parasitic offspring. We investigated nest defence in great reed warblers (Acrocephalus arundinaceus) against three types of nest intruders while controlling for the number of chicks and the length of the nestling period. The most parsimonious linear mixed-effects model showed that the type of intruder and nest identity significantly explained variation in host aggression. Our results demonstrated that the hosts discriminated two predators from an innocuous species and that some nest owners consistently defended their nests more intensely than others. However, the birds did not differ in their responses in relation to the nest contents, indicating that neither the nestling species, nor the length of previous parental investment influenced the intensity of nest defence. Our findings are, therefore, in accordance with the general scarcity of chick discrimination by cuckoo hosts. [ABSTRACT FROM AUTHOR]

Colour and speckling of avian eggshells play important roles in egg recognition behaviour. However, only a few studies have paid attention to whether specific parts of eggs may be more important than others in rejection decisions by hosts. We hypothesised that the blunt pole in song thrush (Turdus philomelos) eggs possesses important cues for recognition of own eggs because this is the most visible part of the egg in the nest. We examined host response towards conspecific eggs painted blue either at the blunt or sharp poles, and used unpainted conspecific eggs as a control. We found, as predicted, that the experimental eggs painted blue at the blunt poles were rejected significantly more often than the experimental eggs unpainted at this pole. Rejection rates of experimental eggs were higher with increasing differences in number of spots between the two poles of own eggs. Our results confirmed that the essential cues used for egg discrimination in song thrushes are found at the blunt egg pole. [ABSTRACT FROM AUTHOR]

We investigated the hypothesis that the common cuckoo Cuculus canorus selects host pairs of good phenotypic quality. As there is some evidence that cuckoos may select hosts within a population non-randomly based on external cues reflecting their foster abilities, we predicted that great reed warbler Acrocephalus arundinaceus pairs parasitized by the cuckoo would exhibit higher quality than unparasitized ones. To test this assumption, we evaluated two different parameters indicating host quality: body condition and characteristics of host eggs. We found that parasitized females showed significantly better body condition than unparasitized ones, and the model showed that the probability of being parasitized by the cuckoos increased with increasing body condition. Moreover, the likelihood of being parasitized by a cuckoo within the great reed warbler population increased with decreasing colour variability within clutches: parasitized females allocated costly blue pigments to eggshells more equally compared with unparasitized ones. Our study revealed that cuckoos parasitize great reed warbler females of higher quality, as reflected in host body condition and egg colour characteristics. In highly mimetic systems, cuckoos may choose to parasitize hosts with eggs displaying low intraclutch variation, both because this leads to reduced rejection and because these hosts are of high quality. [ABSTRACT FROM AUTHOR]

Begging behavior of nestlings can signal both hunger and competitive ability. Studies of begging in evicting avian brood parasites exclude the influence of nestling competition and may provide new insights into the host–parasite conflict and the evolution of signaling. Apart from the begging call, common cuckoo Cuculus canorus nestlings use special vocal displays in the absence of their hosts, termed here host-absent vocalization (HAV). Since these conspicuous calls can increase the risk of predation and require energy, their costs should be balanced by some benefits, such as increased food provisioning. However, there has been no evidence that chicks convey information about their hunger by HAV. We therefore tested experimentally whether cuckoo chicks use HAV as an additional signal to enhance food-delivery rate by their hosts. We used playback of HAV recorded from cuckoo nestlings to determine whether their hosts, reed warblers Acrocephalus scirpaceus, increase their provisioning in response to an apparent increase in HAV. Older chicks spent more time in HAV than younger chicks, suggesting that HAV is not caused by inaccurate discrimination of host arrival stimuli. Negative correlation of HAV with feeding rate and mass gain between the two experiments suggested that hunger was the motivation of HAV. The playback experiment, however, did not prove that HAV affects host provisioning rate. We discuss possible reasons for this result and provide alternative explanations for HAV, such as creating a bond between the hosts and the parasitic young used later in the postfledging care. [ABSTRACT FROM AUTHOR]

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Because there is a lack of wood resources in many countries, this work focused on pulp and paper production from the waste and agricultural residues of non-wood plants. The work aimed to pulp the nitrate-alkaline of black mustard (Brassica Nigra L.) and camelina (Camelina Sativa L.). The black mustard and the camelina were selected due to the expanding planted areas of these crops in the Czech Republic. To characterize the chemical composition of black mustard and camelina, cellulose, lignin, ash, and extractives were determined. Raw alpha-cellulose, beta-cellulose, and gamma-cellulose were also measured. The results showed that the content of lignin in non-wood plants is lower than that in softwoods. The cooked pulp was characterized by the delignification degree–Kappa number. Additionally, handsheet papers were made for selected samples of pulp. The handsheet papers were characterized by tensile index, breaking length, and smoothness and compared with commonly available papers. [ABSTRACT FROM AUTHOR]