Filters
Day-after impact of simulated rival encounter in the common cuckoo
AbstractStudies show that the common cuckoo exhibits a strong vocal response to rival playback. In this study, we aimed to assess if males would more eagerly vocally defend their home ranges a day after a simulated rival encounter. At 48 sites in Poland, we conducted a playback experiment where we played 20 calls repeated 5 times with a 5-min break between each series. Using the automatic analysis software Kaleidoscope Pro, we detected cuckoo calls in two datasets, directly after the experiment and the day after. Our results show that even though cuckoos respond to rival calls, this response is short-lived.
Impact of bisphenol A and ethinyloestradiol on sex, body condition and digit ratio of the marsh frog Pelophylax ridibundus in the mesocosm exposure system
Mobbing behaviour of hosts and non-hosts towards cuckoo Cuculus canorus of different sex
AbstractThe common cuckoo Cuculus canorus is an obligate brood parasite of many Eurasian bird species that exploit the parental care of their hosts. Although only females lay eggs in nests of passerine hosts, male and female cuckoos should cooperate to have a success in nest parasitism. Many bird species mobbing cuckoos as an element of deterrence of cuckoos from the breeding territory of the host. However, mobbing behaviour is costly, although only cuckoo females pose a threat to the dangers of the host. Because only the presence of a female cuckoo is dangerous, due to laying eggs in the nests of hosts, birds should mainly attack cuckoo females. Therefore, we tested for differences in anti-parasite response using field experiments with female and male cuckoo dummies, in 92 breeding sites with prime habitats in Poland. tested for differences in cuckoo responses in anti-parasite response using field experiments and cuckoo dummies (male and female) placed at 92 breeding sites with prime habitats in Poland. The host species that behaved most aggressively towards cuckoos was the barn swallow Hirundo rustica, while the most aggressive behaviour recorded in the non-host group was the great tit Parus major. Generally, host species reacted to cuckoo female dummies with a significantly higher probability than cuckoo males dummies. We conclude that differences in reaction by hosts and non-hosts may have arisen from selection for recognition of danger (parasite female) by reduction of reproductive success.
Common cuckoo vocalisations as an indicator for the avian diversity – A study with passive acoustic monitoring
Head and body orientation of the White Stork Ciconia ciconia during incubation: effect of wind, apex predators and power lines
AbstractIncubation behaviour is essential for understanding the reproductive success in birds. For example, the orientation of the bird is important for reducing incubation costs associated with wind or sun, but on the other hand can be modified by the perceived risk of predation. We studied the body position of incubating White Stork Ciconia ciconia in eastern Poland using a small unmanned aerial vehicle (drone). The head and body orientation of the incubating storks was non-random and modified by natural factors, mainly wind direction and speed, but also by the presence of an apex predator, the White-tailed Eagle Haliaeetus albicilla. However, head orientation during incubation in nests located on electricity poles was also modified by the presence of the power lines, probably due to disturbance in the magnetic field detected by birds. Surprisingly, although the positioning of incubating birds (mainly females) is very important for the detection of predators and for reducing energy costs, these have not previously been studied. New technologies, such as drones, make it possible to collect new, extensive information on the incubation behaviour of birds.
To stay or to go: an analysis of fledging timing in White Stork Ciconia ciconia fledglings
Abstract Fledging is a critical stage in the life of altricial birds, marking their transition from nest dependence to independence. This study examines the timing of nest-leaving in White Stork (Ciconia ciconia) fledglings, focusing on how factors such as day of the year, brood size, chick age, habitat, and temperature influence the onset of fledging. Between 2012 and 2023, 121 fledglings in southern Poland were tagged with solar-powered GPS–GSM loggers to track their departure from nests. Our findings indicate that fledging occurred, on average, at 67 days after hatching, with most fledglings leaving their nests around 6–7 h after sunrise, typically during the late morning (median: 11.00 h local time). However, diel fledging times varied widely, with some chicks leaving as early as sunrise and others as late as 23.00 h. Brood size had a significant impact on fledging behaviour: older chicks in larger broods tended to fledge later in the day, while this pattern was not evident in smaller broods. Environmental factors, such as temperature and habitat type, had no significant effect on timing of fledging. However, fledging time exhibited a non-linear relationship with date, with chicks departing later in the morning in mid-July but earlier in the day by early August, possibly due to changing day lengths and the pressures of migration. This study provides new insights into the complex factors that influence fledging in White Storks, highlighting the role of sibling competition and seasonal variations in shaping fledging behaviour.
Investigating Sexual Characteristics in Two Frog Species Under Exposure to River Water Polluted with Endocrine Disruptors
Endocrine-disrupting compounds (EDCs) are emerging environmental pollutants that are known to the disrsupt hormonal system of many vertebrates. Amphibians, with their aquatic larval stages and high sensitivity to waterborne contaminants, are especially vulnerable to EDC exposure. Despite increasing concerns over EDC pollution, systematic monitoring of these compounds in surface waters remains limited in many regions, including the European Union. This study investigates the effects of water from the Warta River, one of the largest rivers in Central Europe, an urban waterway subjected to significant anthropogenic pressure and known to contain EDCs on body condition, digit ratio, and gonadal development in two brown frog species: the common frog Rana temporaria and the moor frog Rana arvalis. We propose DR as a potential biomarker of endocrine disruption, as it is linked to hormonal impact in the early development of vertebrates. In this study, tadpoles were reared in the semi-open experimental setup with tanks containing river or potable tap water as a control. Contrary to expectations, no significant differences were observed in body condition, digit ratio, or gonadal structure, suggesting that EDC concentrations in the river water may not have been high enough to induce detectable effects. However, a consistent relation between DR and sex was observed in both species, underscoring its potential as a biologically meaningful trait. Notably, the potable tap water used as a control exhibited contamination levels comparable to the river water, raising concerns about the efficacy of current water treatment methods and highlighting the challenges of establishing true reference conditions in environmental studies.
Relationships between pesticides, polychlorinated biphenyls, blood parameters and oxidative stress of white stork Ciconia ciconia chicks in Poland
AbstractThe white stork Ciconia ciconia is a bird species located at the top of the trophic pyramid in grassland and wetland ecosystems. This charismatic species is susceptible to pesticides and their environmental residues. In 2016, we collected blood samples from 114 white stork chicks across Western and Southern Poland. Chicks were sexed by molecular analysis and aged by development pattern. We studied the relationship between the concentration of pesticides (beta-HCH, heptachlor, aldrin, endrin, 4.4′-DDD, 4.4′-DDE and 4.4′-DDT) and of PCB in the chicks’ blood with blood morphology and biochemistry parameters in the blood. The mean (± SD) values of concentrations of above detection level pesticides were: for (1) beta-HCH 4.139 ± 19.205; (2) 4.4′-DDE 9.254 ± 91.491 and additionally (3) PCB 16.135 ± 44.777 ppb. We found negative relationships between beta-HCH and oxidative stress enzyme activity in the blood, between beta-HCH and leukocyte concentration and between 4.4′-DDE and catalase activity. We also found a positive relationship between the concentration of pesticides in blood and the age of chicks. Interestingly, we found a higher concentration of PCB in the blood of male stork chicks than in female stork chicks. We provide more evidence that the presence of pesticides in the environment can be a strong stress factor, shaping the health status of birds.
Rozwój badań nad bocianem białym Ciconia ciconia w Polsce: test trafności prognoz sprzed ćwierćwiecza
A diet perspective on the impact of the COVID-19 lockdown on urban bird assemblages
The COVID‐19 pandemic, which significantly altered human activities, particularly in urban areas, presented a unique opportunity to explore the dynamics of wildlife–human coexistence. In this study, we conducted bird counts in 36 parks in Poznań, Poland, before (2019) and during (2020) the pandemic lockdown, and assessed the impact of lockdown‐induced changes in human activity on the presence of birds with different diet type in the city. We found a notable decrease in the occurrence of granivorous and waste‐feeding birds in urban areas during the pandemic, but the presence of birds feeding mainly on other food sources remained relatively unchanged. This study provides initial evidence of a cross‐species and diet type‐related decline in bird diversity in urban parks during the COVID‐19 pandemic.
White stork Ciconia ciconia nests as an attractant to birds and bats
AbstractWhite storks (Ciconia ciconia), an emblematic bird of high conservation interest, build massive nests which are also important breeding sites for other birds. However, their role as a potential source of food for foraging birds and bats is unexplored. In this study, we counted insectivorous aerially foraging birds (swallows, martins, and swifts), sparrows, and bats foraging around 51 pairs of white storks’ nest and control sites in Poland. The number of birds was significantly higher near active white stork nests than control sites, but this effect was invisible for bats. White storks provide important benefits to the conservation of co-occurring species.
Syntactically aberrant vocalization in cuckoos disrupts communication but triggers host responses
What factors affect the ‘flocking’ of birdwatchers during bird rarity observations?
Abstract Detecting rare bird species is an essential aspect of ornithological culture. The pursuit of observing rare bird species is not only a key facet of birdwatching tourism but also a fascinating intersection between ornithology and sociology. However, patterns in birdwatcher gatherings around rare birds and the factors affecting these patterns in situ are largely unexplored. We directly asked 50 birdwatchers and analysed available photos to obtain details on birdwatcher gatherings at the occasion of 103 observations of 71 rare species recorded in 1996–2022 in Poland. Our analysis revealed that the number of people participating in rare bird observations was influenced by the rarity status of the species (rarer species attracted larger groups), the year (with an increase in recent years) and the interaction between these factors (there was an increasing trend for birdwatchers to ‘twitch’, that is participate in sightings of very rare bird species, in recent years). Furthermore, distance to urban centres significantly negatively affected the size of birdwatcher groups. In addition, we found that the proportion of observers who successfully saw a birding rarity at each site decreased in recent years but increased during the weekend. We also found that the proportion of women in these crowds has grown in recent years and that female birdwatchers were more willing to participate in observations of more common rarities than male birdwatchers. Our results indicate that birdwatching gatherings around bird rarities can be impacted by several factors, including the general rarity of species, year and distance to cities. A dynamic increase in the proportion of females participating in birdwatching in Poland resembles trends reported in other countries. Increased female engagement in observations of more common rarities may be potentially influenced by distinct motivations. Read the free Plain Language Summary for this article on the Journal blog.
Reactions of wintering passerines to male calls of the European cuckoo Cuculus canorus
AbstractThe reaction of birds to the nest parasite, the European cuckoo Cuculus canorus, has been the subject of extensive testing in various aspects. However, while the cuckoo is a long-distance migrant, some of its hosts are sedentary species. In this study, we aimed to investigate whether species, primarily hosts, react to the presence of the cuckoo also in the winter season. This behaviour may involve an attempt to drive the parasite away from locations that will subsequently become their breeding sites. During playback experiments conducted in the winter of 2021/2022 in Poland, we demonstrated that numerous bird species react to the male cuckoo calls in winter. These calls may be perceived as a source of danger, particularly by cuckoo hosts, who responded to this call more frequently than non-hosts and the control species (pigeon). Nonetheless, the birds’ reactions were not strong, as they did not approach the source of the call. However, our results are constrained by the limited number of cuckoo host species wintering in Poland. To better evaluate the intensity of bird responses to the male cuckoo’s call during the non-breeding season, further studies should be conducted in regions where a greater variety of species, especially those most susceptible to parasitism, overwinter.