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Mites Living in the Nests of the White Stork and Black Stork in Microhabitats of the Forest Environment and Agrocenoses
The White Stork (Ciconia ciconia) and the Black Stork (Ciconia nigra) are well-known model organisms for the study of bird migration, as well as the selectivity of nesting sites and the choice of living environment. The former breeds mainly in open areas, while the latter inhabits forest areas. The acarofauna, and in particular Oribatida, inhabiting the nests of these species, has not been thoroughly explored so far. Therefore, we analyzed the material collected from 70 White Stork nests and 34 Black Stork nests in Poland, between Poznań and Rawicz, and in Kampinos National Park. Our research has increased the faunal and ecological knowledge of the mite fauna inhabiting the nests of large migratory bird species. Oribatida constituted 5–12% of the total mites identified in the nests of White and Black Storks. Their average number was several times higher in the Black Stork nests (80.2 individuals in 500 cm3). Also, the species diversity of moss mites was greater in the Black Stork nests (47 species). In total, the nests of the two stork species were inhabited by 62 moss mite species, with only 22 recorded in both the White and the Black Storks’ nests. The most numerous species included Ramusella clavipectinata, R. fasciata, Oppiella subpectinata, Acrogalumna longipluma, and Scheloribates laevigatus. In addition, we found that juvenile oribatid mites accounted for 0.6% of all the mites in the White Stork nests, with tritonymphs having the largest share, while juveniles in the Black Stork nests comprised 1.4%, of which larvae and protonymphs had the largest share. Our research shows that the nests of large migratory birds provide living space for many mite species. In addition, we noted the potential importance of White and Black Stork nests for mite dispersion and the evolution of interspecies interactions.
The usefulness of unmanned aerial vehicles (UAV) in white stork censusing
AbstractUnmanned aerial vehicles (UAV) are effective and often noninvasive tools successfully used in bird monitoring. However, when handling long-term data in the context of population changes, the consistency of methods over time is essential as the method-related bias may lead to wrong conclusions. In two distinct populations of white storkCiconia ciconia,in Poland and Spain, we compared two censusing methods: traditional observation by a human from the ground and using UAV. We recorded the number of recorded fledglings, the time needed to obtain this information, and the number of detected breeding pairs in colonies. We investigated 57 and 117 nests in Poland and Spain, respectively. In Poland and Spain, the number of fledglings was significantly lower when recorded by human observer than by UAV, i.e., 2.21 vs. 2.60 and 1.35 vs. 1.55. The probability of mistakenly recording the number of fledglings by the observer was significantly lower in colonial white storks in Spain than in solitary nesting in Poland. The mean time needed to record the number of fledglings was significantly longer when using a UAV than by a human observer in both populations. The mean number of detected nests in colonies in Spain differed significantly between the human observer and UAV, 13.1 vs. 7.4, respectively. The difference between human and UAV in recorded pairs was higher when colonies were on trees than on human-made structures. We conclude that introducing UAVs in long-term studies may affect the results and should be performed cautiously.
The prevalence of anthropogenic nest materials differs between two distinct populations of migratory birds in Europe
AbstractA major impact of human development is the transformation of natural habitats into farming lands and the expansion of built-up areas. Also, plastic pollution is affecting wildlife on a global scale. Discarded plastic is ubiquitous and accessible for birds, which can incorporate them into the nest structure. Here, we describe the differences in type, prevalence, and the amount of anthropogenic nest materials between two populations of terrestrial, mainly farmland bird, the white storkCiconia ciconia, on a broad geographical scale, from two migratory divides—eastern in Poland and western in Spain (in total 303 nests). In the two populations, we detected significant differences in the incorporation of anthropogenic nest material, as measured by the Human Footprint Index (HFI) and the Impervious Surface Areas (ISA). We found that ISA was positively related to anthropogenic nest material incorporation in the Spanish population, and HFI was positively related to anthropogenic nest material, in contrast to the Polish population, in which the relationships were not significant. Moreover, we showed that the prevalence of nests with anthropogenic nest material was two times higher in Spanish than in the Polish white stork population. This study demonstrates that the behavior of incorporation of the anthropogenic nest material differs between two distinct populations of a single bird species.
Are external head measurements a reliable predictor of brain size in the Common Quail (Coturnix coturnix)?
Comparative research conducted during the past two decades revealed ecological and evolutionary consequences of interspecies differences in relation to brain size. However, relatively much fewer studies have focused on intraspecific variation in brain sizes. This may arise from the lack of a reliable and universal methodology to estimate brain size that can be employed in wild populations in vivo and in a minimally invasive manner. Here, we assessed whether variation in brain mass of Common Quails ( Coturnix coturnix (Linnaeus, 1758)) was predicted by external measurements of the head. Contrary to previous work, we found that the height of the head and not the volume of the head was the best predictor of brain mass in the Common Quail. However, we found that the height of the head explained only a relatively small proportion of variance in brain masses (i.e., 74.4%). Our data suggest that the external measurements of the head may not represent a universally applicable methodology to estimate brain sizes in birds and should, therefore, be used cautiously and validated for the studied species.
Controlled expression of avian pre-migratory fattening influences indices of innate immunity
ABSTRACT While immunity is frequently dampened when birds engage in strenuous migratory flights, whether and how immunity changes during the rapid accumulation of energy stores in preparation for migration remains largely unknown. Here we induced pre-migratory fattening through controlled changes of daylight in common quails (Coturnix coturnix) and regularly assessed changes in three markers of constitutive innate immunity (leukocyte coping capacity or LCC, hemagglutination and hemolysis titres) and measures of body composition (lean and fat mass). All the three markers showed similar changes over the pre-migratory fattening process. LCC responses, hemagglutination titres, and hemolysis titres, were on average higher in the mid-fattening phase compared to the peak-fattening phase, when values were similar to those observed prior the start of pre-migratory fattening. At mid-fattening, we found that the birds that showed a larger accumulation of fat mass (as % of body mass) had lower LCC peak responses and hemolysis titres. Reversibly, at mid-fattening, we also found that the birds that kept a higher proportion of lean mass (as % of body mass) had the highest LCC peaks. Our results indicate that migratory birds undergo changes in immune indices (over 8 weeks) as they accumulate energy stores for migration and propose that this could be due to competing or trade-off processes between metabolic remodelling and innate immune system function.
Age-related nest-site segregation in a solitary nesting population of white stork Ciconia Ciconia
Abstract Background Habitat selection plays a crucial role in avian reproductive success, with nest-site characteristics and individual traits influencing breeding outcomes. This study investigates the relationship between breeder’s age and nest-site selection in a population of white storks Ciconia ciconia, a long-lived, site-faithful species nesting solitarily in Western Poland. Using data collected from 2006 to 2024 on ring recoveries, nest dimensions, productivity, and habitat characteristics, we analyzed the age at which birds were first recorded on specific nests. Results Results revealed that older individuals were more likely to occupy larger nests and nests with higher productivity in previous years, suggesting the use of public information and a preference for high-quality sites. Interestingly, nest surface area, rather than height, was correlated with breeder’s age, while land cover surrounding the nest had a sex-specific effect. Older individuals also appeared to prefer nests with higher occupancy rates. Older females avoided human-altered habitats, whereas no such relationship was observed for males. Contrary to expectations, age-related differences were not associated with preferred foraging habitats like meadows and pastures. Conclusions These findings highlight that age-based segregation in nest-site selection reflects experience and competition, with older birds optimizing breeding success by leveraging key environmental and social cues. The results suggest that younger individuals may occupy suboptimal habitats, possibly due to competition or inexperience. Future studies should explore the role of site fidelity, age-assortative mating, and anthropogenic influences, such as supplementary feeding, to fully understand the dynamics of nest-site selection in white storks.
Citizen science data can significantly improve predictions of potential ranges of non-charismatic species: a study on two freshwater sponges
Rozwój badań nad bocianem białym Ciconia ciconia w Polsce: test trafności prognoz sprzed ćwierćwiecza
Brain size mediates the choice of breeding strategy in the red‐backed shrike Lanius collurio
AbstractThe brain size of vertebrates represents a trade‐off between natural selection for enhanced cognitive abilities and the energetic constraints of brain tissue production. Processing information efficiently can confer benefits, but it also entails time costs. Breeding strategies, encompassing timing of breeding onset and nest‐site selection, may be related to brain size. In this study, we aim to elucidate the relationship between brain size, breeding timing, nest‐site choice, and breeding success in the red‐backed shrike Lanius collurio. Our findings revealed that the timing of the first egg‐laying date was associated with female head size, with larger‐headed females tending to lay eggs later in the breeding season. Additionally, we observed that breeding success was positively correlated with increased nest concealment. However, this relationship was stronger in males with smaller heads. In turn, nest concealment was not related to head size but primarily influenced breeding onset. These results suggest that the choice of breeding strategy may be moderated by brain size, with differences between sexes. Larger‐headed females may invest more time in selecting nesting sites, leading to delayed breeding onset, while larger‐headed males may compensate for suboptimal nest concealment. Our study sheds light on the intricate interplay between brain size, breeding timing, nest‐site preferences, and breeding success in passerine birds, underscoring the potential role of cognitive capacity in shaping individual decision‐making processes.
Eggshell coloration is related to condition of females and offspring but not to male provisioning effort in a cup-nesting passerine
Abstract Pigments present in avian eggshells are thought to serve many different adaptive functions. According to the sexually selected eggshell coloration hypothesis, the quantity of pigments in eggshells can serve as a signal of a female’s condition or of her maternal investment into eggs that elicits a higher investment from her partner. Here, we employed a comprehensive approach to test the sexually selected eggshell coloration hypothesis using a cup-nesting passerine with protoporphyrin-pigmented eggshells, the red-backed shrike Lanius collurio, as our model species. We used calibrated digital photography and visual modelling to assess eggshells appearance from an avian point of view. We estimated the condition of chicks and adult females using the Scaled Mass Index and additionally measured average width of growth bars on rectrices of adult females. We quantified the investment of males in terms of provisioning rates to offspring. We found that females in worse condition laid eggs with redder spots and the redness of spots was positively related to the condition of chicks. Visual modelling revealed that males were likely to perceive the variation in colour and brightness among clutches in the studied population, however, the provisioning rates of males were not related to any aspect of eggshell appearance. Thus, while eggshell coloration can act as a cue of female condition, we found no support for the signalling function of eggshell coloration in post-mating sexual selection in the red-backed shrike.
Age, brood fate, and territory quality affect nest-site fidelity in white stork Ciconia ciconia
Abstract Background A particular type of site fidelity is faithfulness to the nest site, where birds are not only reoccupying breeding territories but also reusing nests built in previous breeding seasons. Staying faithful to the nest site is believed to be an adaptive strategy, and based on the ability to predict an individual's own breeding success, a hypothesis of “win-stay:loose-switch” was proposed. In this study, we aimed to resolve which factors affect the nest-site fidelity of white stork Ciconia ciconia, species known for reusing nests available in the breeding sites. Basing on ring recoveries from 31 years of studies in Western and Southern Poland, we analysed the impact of intrinsic and extrinsic factors on nest-site fidelity. Results We found that increasing age and breeding success (i.e. producing any fledglings or not) increased the probability of reusing the nest, but in the oldest individuals, the probability decreased. In turn, the probability of breeding success increased with age, the increasing number of reproductive events on the particular nest, and the presence on the nest in the previous year. However, the oldest individuals had lower probability of success, as the relationship was curvilinear. The number of fledglings, however, was influenced only by an individual's age. The number of reproductive events on the nest was, in turn, affected by age, with the youngest and oldest individuals using the current nest for the least number of years. Conclusions Our study shows that the decision process of whether to stay faithful to the nest or switch is based on the experience from the previous breeding event, consistently with the “win-stay:loose-switch” hypothesis. Our results also show that site fidelity benefits white storks, as the probability of breeding success increases if the nest is reused. Results also show the senescence effect that lowers breeding success and site fidelity probabilities.