Papers by Denitza Pavlova
Animal Biology, 2010
In contrast to male bird song, female song complexity, learning and expression have received much... more In contrast to male bird song, female song complexity, learning and expression have received much less attention. Female European starlings can produce song of a comparable complexity as males and are also capable of adult vocal learning. Here we recorded song during 3 successive years and investigated variation in song traits (song complexity, song duration and song versatility) in relation to age in captive adult female starlings. We looked at whether individual song traits diff er among diff erent age classes (crosssectional analyses) and whether they change over successive years (longitudinal analyses). Further we studied the repertoire turnover throughout the years, female song sharing in the fi rst year of recording and whether diff erent song traits consistently vary among females across the years. Overall, both cross-sectional and longitudinal analyses showed that repertoire size signifi cantly declined with female age, suggesting that some constraints exist in adult females to maintain large repertoires. Song duration and song versatility appeared to be unrelated to age. Female starlings intensely modifi ed their repertoire across the years by adding new/deleting old phrase types, suggesting a high plasticity as reported in males. Females showed a high variation (between 14% and 83%) in sharing their repertoire, with older females having higher song sharing rates. Th e individual diff erences in song complexity and performance were repeatable across the years, which may suggest that song in female starlings is a potential quality indicator trait.
The Condor, 2005
While male song and its functions have been well studied, female song has often been overlooked. ... more While male song and its functions have been well studied, female song has often been overlooked. In this study, we provide a detailed description of the spontaneous female song in a well-studied northern temperate songbird, the European Starling (Sturnus vulgaris). We compared the song organization, complexity, and composition of female and male starlings housed in large outdoor aviaries. Overall, the general organization was similar in both sexes, and some females sang complex song bouts of more than 30 seconds of uninterrupted song. Although some females were capable of singing the four phrase-type categories typically found in male song bouts (whistle, variable, rattle, and high-frequency phrase types), a significantly lower proportion of females sang all four categories of phrase type as compared to males. Our results also revealed large individual variation in song characteristics among females: repertoire size varied between 11 and 36 phrase types, while average song bout length ranged between 10 and 26 seconds. All song parameters (total repertoire size, song bout length, and repertoire size within the four different phrase categories) were significantly lower in females than in males. Nevertheless, except for the number of rattle phrase types, song parameters overlapped between the sexes demonstrating that some females produced a more complex song than some males.
Behaviour, 2007
Nearly all studies on seasonal changes in song behaviour have focused on male songbirds and detai... more Nearly all studies on seasonal changes in song behaviour have focused on male songbirds and detailed studies on seasonal patterns of song activity in females are lacking. Here, we present information on the annual cycle of song activity in female European Starlings (Sturnus vulgaris) housed in a large outdoor aviary in a single-sex situation (except for the breeding season when males were introduced) and examine social and environmental factors motivating singing behaviour. Female song activity varied significantly throughout the year and was highest during December-mid April. Little or no song was produced when males were present (mid April-June) and in July. With these exceptions, females produced song in every month of the year. A high proportion of females occupied a nestbox throughout the year. Females occupying a nestbox sang significantly more than females without a nestbox, independently of the period. During March and early April females owning a nestbox sang significantly more in their nestbox and/or defended it more often, suggesting that song in that period is produced in the context of intrasexual competition. There was a large individual variation in song rates among females. Furthermore, song rates of individual females were repeatable across the year.
Behaviour, 2007
Environmental, contextual or social factors influencing song in female songbirds have been little... more Environmental, contextual or social factors influencing song in female songbirds have been little studied. Female European starlings Sturnus vulgaris sing robustly throughout most of the year, except during the breeding season when their song production dramatically decreases. Here we experimentally investigated the effect of the presence of males and/or nestboxes on song production in captive female starlings during the breeding season. Spontaneous song activity of two experimental groups and one control group (housed with nestboxes, but no males) was observed for one month from the end of March onwards. Additionally, we tested whether female song rate is related to oestradiol plasma levels. The experimental results showed that song rate significantly decreased with the progressing of the breeding season and this process seemed not to be regulated by oestradiol. Nestboxes clearly promoted song production, as previously found in male starlings, while the presence of males negatively affected female song rate. Taken together these results indicate that, in the course of the breeding period, the suppressive influence of the day length and the presence of males on female song production override the stimulating effect of nestboxes, and that engagement in breeding activities is largely incompatible with singing in female starlings.
Marine litter is a complex problem and recognised as a major and growing environmental concern (U... more Marine litter is a complex problem and recognised as a major and growing environmental concern (UNEP, 2009). It threatens marine ecosystems and biodiversity (e.g. through ingestion or entanglement by marine species) and ultimately risks human well- being by damaging socioeconomic activities (e.g. losses to fishing or clean up costs) and posing health risks (e.g. ingestion of plastics through the food chain) (EEA, 2015). Marine litter originates from div erse and various, sources both land and sea -based, and the types of items which end up in the world's seas and oceans are both varying and numerous (UNEP, 2009). Those often identified include plastic caps and lids, bottles, plastic bags, hygiene products, food containers, fishing nets, and cigarette butts (Interwies et al. 2013). These items can be found in great quantities on the ocean floor, in the water column, floating at sea, and along shorelines and coasts (UNEP, 2009). Exasperating the issue of marine litter is the signi...
The Condor, 2005
While male song and its functions have been well studied, female song has often been overlooked. ... more While male song and its functions have been well studied, female song has often been overlooked. In this study, we provide a detailed description of the spontaneous female song in a well-studied northern temperate songbird, the European Starling (Sturnus vulgaris). We compared the song organization, complexity, and composition of female and male starlings housed in large outdoor aviaries. Overall, the general organization was similar in both sexes, and some females sang complex song bouts of more than 30 seconds of uninterrupted song. Although some females were capable of singing the four phrase-type categories typically found in male song bouts (whistle, variable, rattle, and high-frequency phrase types), a significantly lower proportion of females sang all four categories of phrase type as compared to males. Our results also revealed large individual variation in song characteristics among females: repertoire size varied between 11 and 36 phrase types, while average song bout length ranged between 10 and 26 seconds. All song parameters (total repertoire size, song bout length, and repertoire size within the four different phrase categories) were significantly lower in females than in males. Nevertheless, except for the number of rattle phrase types, song parameters overlapped between the sexes demonstrating that some females produced a more complex song than some males.
Behaviour, 2007
Environmental, contextual or social factors influencing song in female songbirds have been little... more Environmental, contextual or social factors influencing song in female songbirds have been little studied. Female European starlings Sturnus vulgaris sing robustly throughout most of the year, except during the breeding season when their song production dramatically decreases. Here we experimentally investigated the effect of the presence of males and/or nestboxes on song production in captive female starlings during the breeding season. Spontaneous song activity of two experimental groups and one control group (housed with nestboxes, but no males) was observed for one month from the end of March onwards. Additionally, we tested whether female song rate is related to oestradiol plasma levels. The experimental results showed that song rate significantly decreased with the progressing of the breeding season and this process seemed not to be regulated by oestradiol. Nestboxes clearly promoted song production, as previously found in male starlings, while the presence of males negatively...
Behaviour, 2008
Take-down policy If you believe that this document breaches copyright please contact us providing... more Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Behaviour, 2007
Nearly all studies on seasonal changes in song behaviour have focused on male songbirds and detai... more Nearly all studies on seasonal changes in song behaviour have focused on male songbirds and detailed studies on seasonal patterns of song activity in females are lacking. Here, we present information on the annual cycle of song activity in female European Starlings (Sturnus vulgaris) housed in a large outdoor aviary in a single-sex situation (except for the breeding season when males were introduced) and examine social and environmental factors motivating singing behaviour. Female song activity varied significantly throughout the year and was highest during December-mid April. Little or no song was produced when males were present (mid April-June) and in July. With these exceptions, females produced song in every month of the year. A high proportion of females occupied a nestbox throughout the year. Females occupying a nestbox sang significantly more than females without a nestbox, independently of the period. During March and early April females owning a nestbox sang significantly more in their nestbox and/or defended it more often, suggesting that song in that period is produced in the context of intrasexual competition. There was a large individual variation in song rates among females. Furthermore, song rates of individual females were repeatable across the year.
Behavioral Ecology, 2007
Although heterospecific vocal imitation is well documented in passerines, the evolutionary correl... more Although heterospecific vocal imitation is well documented in passerines, the evolutionary correlates of this phenomenon are poorly known. Here, we studied interspecific variation in vocal mimicry in a comparative study of 241 European songbirds. We tested whether vocal mimicry is a mode of repertoire acquisition or whether it resulted from imperfect song learning. We also investigated the effect of the degree of contact with the vocal environment (with species having larger ranges, abundance, or being long lived having a higher degree of mimicry) and a possible link with cognitive capacity (an overall larger brain in species with mimicry). Finally, we determined the potential evolutionary role of vocal mimicry in different interspecific contexts, predicting that mimicry may affect the intensity of brood parasitism, predation, or degree of hybridization. While controlling for research effort and phylogenetic relationships among taxa, we found that effect sizes for intersong interval, brain size, breeding dispersal, abundance, age-dependent expression of repertoires, and predation risk reached a level that may indicate evolutionary importance. Vocal mimicry seems to be a consequence of song continuity rather than song complexity, may partially have some cognitive component but may also be dependent on the vocal environment, and may attract the attention of predators. However, estimates of sexual selection and interspecific contacts due to brood parasitism and hybridization varied independently of vocal mimicry. Therefore, mimicry may have no function in female choice for complex songs and may be weakly selected via interspecific associations. These findings provide little evidence for vocal mimicry having evolved to serve important functions in most birds.
Behavioral Ecology, 2006
Bird song is usually regarded as an attribute of males. However, in some species, females may als... more Bird song is usually regarded as an attribute of males. However, in some species, females may also produce songs even with comparable complexity to that of males. It has been suggested that female song may evolve due to similar selection pressures acting on males, but no study has yet investigated the evolution of female vocalization in a phylogenetic context, a gap that we intended to fill with this study. Based on standard descriptions in The Birds of Western Palearctic, we classified 233 European passerine species with respect to whether females are known to produce songs or not. We were more likely to find information on female song for species whose song is more studied than for less intensively studied species. When we traced information on female song on a phylogeny, we found that at least in 2 avian families, female song appeared to be the ancestral state, but such an ancestral state may be expected to be even deeper in the phylogenetic tree with increasing information on female song. In fact, we cannot exclude the possibility that the ancestor of European passerines had females capable of singing. In a preliminary comparative study based on the available data, we found some evidence that female song may have evolved under the influence of sexual selection as carotenoid-based dichromatism was positively related to female song among species. Our findings imply that due to publication bias, the evolutionary importance of female song is generally underestimated.
Animal Biology, 2010
In contrast to male bird song, female song complexity, learning and expression have received much... more In contrast to male bird song, female song complexity, learning and expression have received much less attention. Female European starlings can produce song of a comparable complexity as males and are also capable of adult vocal learning. Here we recorded song during 3 successive years and investigated variation in song traits (song complexity, song duration and song versatility) in relation to age in captive adult female starlings. We looked at whether individual song traits differ among different age classes (cross-sectional analyses) and whether they change over successive years (longitudinal analyses). Further we studied the repertoire turnover throughout the years, female song sharing in the first year of recording and whether different song traits consistently vary among females across the years. Overall, both cross-sectional and longitudinal analyses showed that repertoire size significantly declined with female age, suggesting that some constraints exist in adult females to ...
NeuroImage, 2006
In temperate zone songbird species, seasonal plasticity in the morphological and functional state... more In temperate zone songbird species, seasonal plasticity in the morphological and functional state of brain regions involved in song production occurs in association with seasonal changes in song output. Following MnCl(2)-injections in HVC (used as proper name) of female starlings, in vivo tract-tracing by Manganese Enhanced-Magnetic Resonance Imaging (ME-MRI) provided repeated measures of the volume of two HVC targets, the nucleus robustus arcopallii (RA) and area X, along with measures of the activity of the caudal motor pathway and rostral basal-ganglia pathway that control singing. Mn(2+)-labeling (volume labeled and signal intensity) of both nuclei was dramatically reduced in July (post-breeding season) when birds did not sing, compared to March (breeding season) when birds produced song. Seasonal changes in telencephalon volume did not exceed 4% and were not significant but were surprisingly correlated with individual measures of song rate and song bout length. Although individ...
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Papers by Denitza Pavlova