Publications

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hierarchical modelling and estimation of abundance and population trends in metapopulation designs.1. population assessment in changing environments is challenging because factors governing abundance may also affect detectability and thus bias observed counts. we describe a hierarchical modelling framework for estimating abundance corrected for detectability in metapopulation designs, where observations of 'individuals' (e.g. territories) are replicated in space and time. we consider two classes of models; first, we regard the data as independent binomial counts and model abundance and detect ...201019886893
food storing and the hippocampus in paridae.food storing passerines have a larger hippocampus, relative to the rest of the telencephalon and/or body mass, than do non-storing species. this study looked at the relationship between relative size of the hippocampus and degree of food storing in six species of paridae (blue tit, parus caeruleus, great tit, p major, marsh tit, p palustris, coal tit, p ater, black-capped chickadee, p. atricapillus, and willow tit, p montanus). the degree of storing by these species varies from little or none to ...19969156782
improved sampling at the subspecies level solves a taxonomic dilemma - a case study of two enigmatic chinese tit species (aves, passeriformes, paridae, poecile).a recent full species-level phylogeny of tits, titmice and chickadees (paridae) has placed the chinese endemic black-bibbed tit (poecile hypermelaenus) as the sister to the palearctic willow tit (p. montanus). because this sister-group relationship is in striking disagreement with the traditional affiliation of p. hypermelaenus close to the marsh tit (p. palustris) we tested this phylogenetic hypothesis in a multi-locus analysis with an extended taxon sampling including sixteen subspecies of wil ...201727965081
to breed or not to breed: causes and implications of non-breeding habit in the willow tit parus montanus.causes and consequences of non-breeding in willow tits were studied in northern finland during 1986-1992. the breeding status was sex and age biased; males and yearling birds were in excess among the non-reproducers. due to sex bias in the population it appeared detrimental for males to lose a mate, especially shortly before breeding. lack of a mate was a important factor for males not reproducing (37% of non-breeding males) than for females (14%). most of the non-breeding birds maintained a pai ...199428307019
hormonal correlates of migration and territorial behavior in juvenile willow tits during autumn.this study compared plasma levels of dihydrotestosterone, testosterone, corticosterone, luteinizing hormone, growth hormone, and prolactin in migrating juvenile willow tits with those in territorial juveniles. both categories of birds were caught in late september. migrating juveniles had higher plasma levels of corticosterone than territorial juveniles. only corticosterone secretion was affected by "handling stress" in both migrating and territorial juveniles. however, territorial birds showed ...19892767404
food storing does not affect hippocampal volume in experienced adult willow tits.food-storing bird species have a larger hippocampal region than closely related non-storing species, and the avian hippocampal region appears to be involved in spatial memory for the locations of stored food. in the present study, willow tits (parus montanus) that were at least 4 years old, had previously stored food, were trained to store and retrieve seeds in an aviary. after training, control birds were deprived of any opportunities to store seeds, while experimental birds stored 17 seeds and ...19968950021
mitochondrial control region polymorphism reveal high amount of gene flow in fennoscandian willow tits (parus montanus borealis).we studied the genetic variability and differentiation of two fennoscandian willow tit (parus montanus borealis) populations located ca. 1000 km apart in finland and sweden by using the control region sequences of the mitochondrial dna. individual variation in the control region was extensive since all the 13 finnish and the 12 swedish individuals had unique haplotypes and the mean pairwise genetic distance resulted in 0.0052 (range 0.0008-0.0109). in the minimum spanning network connecting the ...19989652233
plasma levels of luteinizing hormone and steroid hormones in free-living winter groups of willow tits (parus montanus).plasma levels of lh, dht, testosterone, and corticosterone were measured for all members in free-living winter flocks of willow tits, parus montanus. hormonal data were related to (1) flock size and (2) age/sex differences. the winter flock defends a large winter territory and shows a well-established social hierarchy in which adults consistently dominate first-year birds. one winter group normally consists of four individuals, two adults and two juveniles. in flocks containing four or five memb ...19846519653
egg recognition abilities of tit species in the paridae family: do indomalayan tits exhibit higher recognition than palearctic tits?recent studies have shown that the closely related cinereous tit ( parus cinereus) and green-backed tit ( p. monticolus) in china display strong egg recognition ability in contrast to tit species in europe, which lack such ability. however, egg recognition in other populations of cinereous and green-backed tits and additional paridae species still requires further research. here, we compared the egg recognition abilities of cinereous tits across china, green-backed tits ( p. m. insperatus) in ta ...202032918406
comparative analysis of hissing calls in five tit species.nest predation often leads to breeding failure and is an important component of natural selection that affects the evolution of nest defense behavior in birds. many tit species give a hissing call as nest defense, but there are few studies of interspecific variation in hissing calls, and whether these are related to nest predation and nesting success. in this study, we compared the hissing calls of five tit species including cinereous tits (parus cinereus), marsh tits (poecile palustris), varied ...202031899274
does diurnal variation in body mass affect take-off ability in wintering willow tits?recently, some empirical studies have shown an effect of body mass on take-off ability in birds, supporting the theory that birds with increased fat loads face a greater predation risk. small wintering birds accumulate fat reserves of about 10% of their fat-free body mass during the day to survive long, cold, winter nights. theoretically, mass-dependent predation risk could be an important factor affecting their daily foraging routines. i studied the take-off ability of wintering willow tits, pa ...19989710481
phylogeography of the eurasian willow tit (parus montanus) based on dna sequences of the mitochondrial cytochrome b gene.the phylogeographic relationships of the trans-palearctic willow tit assemblage were studied by obtaining sequence data from the mitochondrial cytochrome b gene from 34 specimens representing nine subspecies from across the species range. four distinct genetic groups were identified: parus montanus weigoldicus, p. m. affinis, p. m. songarus, and a clade containing six eurasian subspecies (ssp. baicalensis, borealis, montanus, restrictus, rhenanus, and sachalinensis). p. m. weigoldicus, p. m. aff ...200212128026
home range size of willow tits: a response to winter habitat loss.we examined the behavioral response to habitat loss and fragmentation of willow tits (parus montanus) in winter in a mosaic forest landscape in northern finland. we studied habitat preference, flock size and home range size of 16 flocks, half of which had their territories in forests fragmented by forestry and half in continuous forest. we predicted that birds would respond to habitat loss by enlarging their home range and/or diminishing group size. in addition, to compensate for fragmentation e ...200312845515
seasonality in daily body mass variation in a hoarding boreal passerine.we studied the body mass variation from autumn to winter, in a free-living population of willow tits ( parus montanus), a food-hoarding passerine living year-round in boreal forests. our aim was to find out whether this population exhibits 'winter fattening' as part of the annual body mass cycle. 'true winter fattening' is considered to be a strategic response to winter conditions. the strategy includes an increase in both the morning mass and the daily mass increase, as winter approaches. a mul ...200314530959
importance of adult survival, local recruitment and immigration in a declining boreal forest passerine, the willow tit parus montanus.population growth rate (lambda) and its components (adult survival, local recruitment, immigration and their relative contributions to lambda) were studied in the declining willow tit parus montanus in northern finland. capture-recapture models for open populations were used to estimate the population parameters and their process variation. adult survival was fairly high with low variation (0.593, cv=0.067). as expected, local recruitment was lower and more variable (0.063, cv=0.610). during the ...200616514536
composition of an avian guild in spatially structured habitats supports a competition-colonization trade-off.assuming better colonization abilities of inferior competitors, the competition-colonization trade-off (ccto) is one of the hypotheses that explains spatial variation of species composition in fragmented habitats. whereas this mechanism may structure some plant and insect communities, ecologists have failed to document its operation in other natural systems, and its generality has been questioned. we combined fieldwork and published data to study the composition of a guild of passerines (parus c ...200717389222
does the temporal mismatch hypothesis match in boreal populations?the temporal mismatch hypothesis suggests that fitness is related to the degree of temporal synchrony between the energetic needs of the offspring and their food supply. the hypothesis has been a basis in studying the influence of climate warming on nature. this study enhances the knowledge on prevalence of temporal mismatches and their consequences in boreal populations, and questions the role of the temporal mismatch hypothesis as the principal explanation for the evolution of timing of breedi ...201425024104
the relevance of food peak architecture in trophic interactions.phenological shifts and associated changes in the temporal match between trophic levels have been a major focus of the study of ecological consequences of climate change. previously, the food peak has been thought to respond as an entity to warming temperatures. however, food peak architecture, that is, timings and abundances of prey species and the level of synchrony between them, determines the timing and shape of the food peak. we demonstrate this with a case example of three passerine prey s ...201626527602
prevalence of avian haematozoa in wild birds in a high-altitude forest in japan.the infection dynamics of avian haematozoa, which includes the genera plasmodium, haemoproteus, and leucocytozoon, are complicated by a variety of environmental factors and host-parasite interactions. in japan, the prevalence of haematozoa in wild birds has recently been determined in several local areas. however, no information on the annual prevalence of avian haematozoa in a single study site has been reported. here, we investigated the long-term infection dynamics of haematozoa in wild birds ...201121831523
low temperatures affect the photoperiodically induced lh and testicular cycles differently in closely related species of tits (parus spp.).photosensitive great tits (parus major) and willow tits (p. montanus) were exposed to long days (20l:4d) under three different temperature conditions (4+, +10, and +20 degrees c) in early winter. the two species showed significant differences in their lh and testicular reaction patterns to low temperatures. testes showed pronounced growth cycles under all temperature regimes. for the willow tit, testes in birds kept at +20 degrees c reached maximum size about 2 weeks earlier than testes in birds ...19947814001
seasonal changes in body weight, fat depots, and plasma levels of thyroxine and growth hormone in free-living great tits (parus major) and willow tits (p. montanus).annual changes in body weight, fat depots, and plasma levels of thyroxine (t4) and growth hormone (gh) were studied in free-living great tits and willow tits. birds were collected during six ecologically well-defined periods of the year. special attention was given to the nonreproductive part of the year. t4 showed simple unimodal cycles in both species and both sexes, with high levels during the warmer part of the year, and low levels during the winter and spring periods. although increasing le ...19892925079
cost of reproduction: parental survival and production of recruits in the willow tit parus montanus.brood sizes of the willow tit were altered experimentally by subtracting or adding two nestlings in 1986 and 1987 in the vicinity of oulu, northern finland. the manipulated broods were within the normal range observed in natural conditions. unaltered broods were used as controls. data from natural broods from 1978-1985 were available for comparison. when the nestlings were 13 days old they were ringed and weighed and their tarsus, wing, and tail lengths were measured. on the same day the parents ...198828311961
reproductive cost, age-specific survival and a comparison of the reproductive strategy in two european tits (genus parus).theoretical analyses of optimal reproductive rates usually assume a trade-off between offspring production and parental survival. this study verified a survival cost for willow tit males; nonbreeding males survived better than males attending a brood. theory also predicts a smaller clutch size in birds that are less successful in transforming reproductive investments into mature offspring. as predicted, we found that crested tits, suffering a higher nest predation rate, laid smaller clutches tha ...198628564125
different post-pleistocene histories of eurasian parids.previous phylogeographic studies of the great tit (parus major) and the willow tit (parus montanus) found a general absence of phylogeographic structure for both species and suggested that each species underwent range contraction during the last ice age and survived in relatively low numbers, p. major in southern europe and p. montanus in southeastern asia. however, prior studies did not sample the entire range of either species. we analyzed sequence data for the complete mitochondrial nd2 gene ...200816844731
different ultimate factors define timing of breeding in two related species.correct reproductive timing is crucial for fitness. breeding phenology even in similar species can differ due to different selective pressures on the timing of reproduction. these selection pressures define species' responses to warming springs. the temporal match-mismatch hypothesis suggests that timing of breeding in animals is selected to match with food availability (synchrony). alternatively, time-dependent breeding success (the date hypothesis) can result from other seasonally deterioratin ...201627611971
evolution of enlarged body size of coal tits parus ater in geographic isolation from two larger competitors, the crested tit parus cristatus and the willow tit parus montanus, on six scandinavian islands.here, we report that on six widely separated scandinavian islands, the coal tit parus ater has evolved morphologically in the direction of two absent competitors, the crested tit p. cristatus and the willow tit p. montanus, to the effect that it is up to 10% larger in linear dimensions than conspecifics on the adjacent swedish mainland, where all three species coexist. the large size is genetically determined, as ascertained by clutch exchange experiments between island and mainland nests. we co ...201526490673
calibration of a molecular clock in tits (paridae)--do nucleotide substitution rates of mitochondrial genes deviate from the 2% rule?the ongoing debate on the reliability of avian molecular clocks is actually based on only a small number of calibrations carried out under different assumptions with respect to the choice and constraints of calibration points or to the use of substitution models. in this study, we provide substitution rate estimates for two mitochondrial genes, cytochrome b and the control region, and age estimates for lineage splits within four subgenera of tits (paridae: parus, cyanistes, poecile and periparus ...200717512759
influence of the opposite sex on photoperiodically induced lh and gonadal cycles in willow tit (parus montanus).in early january photosensitive willow tits (parus montanus) were transferred from natural to long days (20l;4d). the study included three groups of birds: one group consisted of pairs (one male and one female kept together in a cage), a second group consisted of males, and a third group included only females. birds from the separate groups could neither see nor hear each other. gonadal and lh cycles were followed over a 2-month period. the reproductive systems of male and female willow tits wer ...19957557923
correlation between two components of parental investment: nest defence intensity and nestling provisioning effort of willow tits.nest defence intensity and nestling provisioning effort of female willow tits (parus montanus) were significantly correlated at the end of nestling period: well-fed young were defended most intensely. increased effort was rewarded, since broods with the highest female per-offspring provisioning rates were the most likely to produce local recruits. this suggests that the feeding ability is an important cue for parental investment decisions, at least in a species like the willow tit which has adop ...199528307596
heavy metal load and dominance hierarchy in juvenile willow tits during winter.possible links between plasma testosterone levels, heavy metal loads and dominance in juvenile male willow tits (parus montanus) are studied during winter conditions in norway. dominant individuals have better access to food resources, significantly higher cadmium content in the liver and higher plasma testosterone level compared to subordinates. a positive correlation was also found between plasma testosterone level and content of cadmium in the liver. although the results in our study shows on ...200717011685
estimation of rates of births, deaths, and immigration from mark-recapture data.the analysis of mark-recapture data is undergoing a period of development and expansion. here we contribute to that by presenting a model which includes both births and immigration, as well as the usual deaths. data come from a long-term study of the willow tit (parus montanus), where we can assume that all births are recorded, and hence immigrants can also be identified as birds captured as adults for the first time. we model the rates of immigration, birth rate per parent, and death rates of j ...200918479483
foraging intention affects whether willow tits call to attract members of mixed-species flocks.understanding how individual behaviour influences the spatial and temporal distribution of other species is necessary to resolve the complex structure of species assemblages. mixed-species bird flocks provide an ideal opportunity to investigate this issue, because members of the flocks are involved in a variety of behavioural interactions between species. willow tits (poecile montanus) often produce loud calls when visiting a new foraging patch to recruit other members of mixed-species flocks. t ...201728680675
microfilariae in birds in the czech republic, including a note on adult nematodes eufilaria delicata in a song thrush turdus philomelos.blood samples of more than 1,100 passerineform birds of 40 species were investigated for the occurrence of microfilariae. in the year 2005, 3 out of 677 birds of 31 species (prevalence 0.4%) were infected with microfilariae during the post-nesting period. during the pre-nesting period in the year 2007, 11 out of 438 birds of 31 species were infected with microfilariae (prevalence 2.5%). both the pre-nesting and post-nesting examinations were conducted at the same location in the northeastern par ...201121400118
different seasonal patterns in song system volume in willow tits and great tits.in most species of seasonally breeding songbirds studied to date, the brain areas that control singing (i.e. the song control system, scs) are larger during the breeding season than at other times of the year. in the family of titmice and chickadees (paridae), one species, the blue tit (cyanistes caeruleus), shows the typical pattern of seasonal changes, while another species, the black-capped chickadee (poecile atricapillus), shows, at best, very reduced seasonal changes in the scs. to test whe ...201627442125
effects of ambient temperatures on evolutionary potential of reproductive timing in boreal passerines.many populations need to adapt to changing environmental conditions, such as warming climate. changing conditions generate directional selection for traits critical for fitness. for evolutionary responses to occur, these traits need to be heritable. however, changes in environmental conditions can alter the amount of heritable variation a population expresses, making predictions about expected responses difficult. the aim of this study was to evaluate the effects of ambient temperatures on evolu ...202033090475
from feces to data: a metabarcoding method for analyzing consumed and available prey in a bird-insect food web.diets play a key role in understanding trophic interactions. knowing the actual structure of food webs contributes greatly to our understanding of biodiversity and ecosystem functioning. the research of prey preferences of different predators requires knowledge not only of the prey consumed, but also of what is available. in this study, we applied dna metabarcoding to analyze the diet of 4 bird species (willow tits poecile montanus, siberian tits poecile cinctus, great tits parus major and blue ...201930680143
mass or pace? seasonal energy management in wintering boreal passerines.research on winter energy management in small vertebrates has focused on the regulation of body mass (bm) within a framework of starvation-predation trade-off. winter-acclimatized birds exhibit a seasonal increase in both bm and basal metabolic rate (bmr), although the patterns of co-variation between the two traits remain unknown. we studied this co-variation in three different species of wild titmice, great, blue and willow tits, originating from two boreal regions at different latitudes. seas ...201930617630
northward expanding resident species benefit from warming winters through increased foraging rates and predator vigilance.species distributions shift northwards due to climate change, but the ecological mechanisms allowing range expansions are not fully understood. most studies have concentrated on breeding seasons, but winter warming may also be important. wintering distributions are restricted by food availability and temperature, which may also interact. foraging in cold conditions requires adaptations as individuals have to be efficient in foraging, while staying warm and vigilant for predators. when the ambien ...201830357531
antioxidant enzyme activities vary with predation risk and environmental conditions in free-living passerine birds.prolonged physiological stress response may lead to an excessive production of reactive oxygen species (ros) and ultimately to oxidative stress and severe fitness costs. we investigated whether natural variation in predation risk, induced by pygmy owls (glaucidium passerinum), modifies the oxidative status of two free-living food-supplemented passerine bird species-the great tit (parus major) and the willow tit (poecile montanus)-in march 2012 and 2013. predation risk significantly affected anti ...201829494281
egalitarian mixed-species bird groups enhance winter survival of subordinate group members but only in high-quality forests.only dominant individuals have unrestricted access to contested resources in group-living animals. in birds, subordinates with restricted access to resources may respond to intragroup contests by acquiring extra body reserves to avoid periods of food shortage. in turn, higher body mass reduces agility and increases predation and mortality risk to subordinates. birds often live in hierarchically organized mixed-species groups, in which heterospecific individuals are considered to substitute for c ...202032132547
habitat quality affects stress responses and survival in a bird wintering under extremely low ambient temperatures.animals normally respond to stressful environmental stimuli by releasing glucocorticoid hormones. we investigated whether baseline corticosterone (cort), handling-induced corticosterone concentration(s), and body condition indices of members of willow tit (poecile montanus) groups differed while wintering in old growth forests and managed young forests in mild weather conditions and during cold spells. willow tits spend the winter season in non-kin groups in which dominant individuals typically ...201729138934
body size, interspecific interactions, and use of foraging sites in tits (paridae).in mixed-species flocks, the heavier tit species forage in the inner tree parts, while the smaller species exploit food items of the outer canopy. using aviary experiments we studied the relative importance of two possible explanations for body size-foraging site correlation. the first hypothesis is that larger bodied tits are more efficient than smaller ones in exploiting the inner tree parts, while the reverse would be true in the outer canopy. however, the heavier species, the willow tit paru ...198729357141
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