Signaling quality in the Middle Spotted Woodpecker Dendrocopos medius: home ranges, colour ornaments and calls

Wydział Biologii: Instytut Biologii ŚrodowiskaSygnalizacja jakości w świecie zwierząt jest zjawiskiem powszechnym i prawdopodobnie występuje również u dzięcioła średniego. Celem pracy jest analiza trzech możliwych płaszczyzn sygnalizacji kondycji i jakości osobnika u tego gatunku. Są to: 1) rozmiar i jakość terytoriów osobniczych, 2) ornamenty barwne w postaci czerwonej czapeczki oraz 3) wokalizacja. W badanej populacji dzięcioła średniego pary różniły się między sobą wielkością zajmowanego areału. Nie stwierdzono międzypłciowych różnic w rozmiarach areałów osobniczych. Osobniki o lepszej jakości zajmowały mniejsze areały. Jakość osobniczą reprezentował indeks kondycji wyliczony na podstawie cech biometrycznych. Samce i samice różniły się rozmiarem barwnego ornamentu na głowie (czapeczki). Nie stwierdzono natomiast różnic w jasności koloru ornamentu wyrażonego reflektancją w spektrum czerwieni. U badanych par stwierdzono wybiórcze kojarzenie pod kątem jasności ornamentu i masy osobników. W wokalizacji dzięcioła średniego wyróżniono 3 typy głosów, których funkcję przebadano eksperymentalnie. Nie znaleziono poparcia dla hipotezy, że głos jest reklamą jakości osobniczej. Stwierdzono natomiast występowanie sygnatury głosowej. Z przeprowadzonych badań wynika, że zarówno ornament w postaci czerwonej czapeczki jak i zajmowany areał osobniczy mogą być nośnikiem informacji o jakości osobnika.The subject of this study is the ecology and communication of the Middle Spotted Woodpecker. The study focuses on vocalization, colour ornaments and territories and their function in signalization of individual quality. During 3 years of field study the differences in home ranges of individuals and pairs were examined. Higher quality birds occupied smaller territories. There was no difference in home range size between males and females. The size, but not brightness, of the red ornament significantly differed between sexes. Higher quality individuals had brighter caps and they also mated assortatively. Middle Spotted Woodpeckers uttered 3 types of calls, one of which was a vocal signature. The other 2 voices functioned as territory and alarm calls

The ecological consequences of solitary breeding in a species with bi-parental care

A higher rate of nestling development reduces their exposure time to predators, which is advantageous but simultaneously it involves an increased parental investment in incubation, brooding and feeding, which may be difficult to obtain by a single parent. An interesting question is whether, and to what degree, a single parent in a typical bi-parental species is able to compensate the lack of its mate’s contribution in species with fast developing nestlings. Our study species is the Blackcap Sylvia atricapilla, a small passerine that experiences high levels of nest predation and rapid development of nestlings. We test the hypotheses that (i) single parents are not able to fully compensate for the lack of mate in rearing a brood and (ii) parents pay cost for breeding alone by increasing the time that the offspring is exposed to predators in the nest. We also inquire in potential trade-off between brooding and feeding and its consequences for nestling growth in nests reared by single parents. Our results show that single parents were able to compensate for the lack of the mate in terms of feeding rate, but this was at the cost of time spent brooding. Nestlings in uni-parental nests grew more slowly and lagged about two days behind their bi-parental counterparts, which may extend nestling exposure time to a predator by about 20%

Equal division of parental care enhances nestling development in the Blackcap.

Because parental care is costly, conflict between mates over their roles in reproduction seems unavoidable unless they both benefit from parental labour split equally between partners. In the current paper we analyse the division of parental investment in the Blackcap (Sylvia atricapilla), a species that experiences high nest predation. We show that both sexes invest in the incubation of eggs as well as feeding and brooding nestlings at a similar level. We also found that pairs which divided feeding duties more equally produced nestlings that grew faster. Faster nestling development enables earlier fledging in case of predation attempts at the end of nesting period. Thus parents who more evenly participate in provisioning may benefit from higher breeding success. Our findings suggest that in species under high risk of nest predation disparity in parental investment may not provide much benefit to parent's residual reproductive value and that equality in parental duties constitutes a winning strategy

Pros and cons of different methods of measuring egg coloration -photocolorimetry vs. spectrometry AVIAN ECOLOGY AND BEHAVIOUR PROCEEDINGS OF THE BIOLOGICAL STATION "RYBACHY"

Color measurement plays an important role in numerous studies on evolution and function of egg coloration. Recent availability of compact, portable spectrometers and digital cameras resulted in considerable number of studies testing different hypotheses with the use of more objective color measurements. Each of the methods, however, has its advantages and limitations. In the present study we evaluate color variation in UV-rich and blue-green European Starling eggs using two different methods -color measurement from digital photography and spectrometric color measurement. Next, based on the values obtained from both devices, we classify the eggs to color categories and we compare the results of the classifications. We found that two measures of egg color intensity -saturation and BGC -were significantly correlated, however classification of blue-green egg color intensity based on saturation values obtained from a digital photography taken in a darkroom reflected egg colors more accurately, at least for human observer, than classification based on BGC values measured by spectrophotometer. We suggest that differences in classification of some eggs using spectrometric measurements may have resulted from the differences in egg glossiness. However, spectrometric measurement allowed analyses of UV component of egg color. The possibility of collecting and analyzing data in this range of the spectrum is the most pronounced advantage of spectrometric measurements of eggs coloration

Organization, variation in time, and impacting factors in the song strophe repertoire in the Great Reed Warbler (Acrocephalus arundinaceus)

The song of the Great Reed Warbler (GRW) is produced by males before and during the breeding season in territory defense and mate attraction. To date, researchers studying the song of the species have mainly focused on syllable repertoire and its function. In this paper we present first data on the organization of strophes and their possible function in the GRW. We analyzed short- and long-term changes in strophe repertoire size and composition and the relationship between strophe repertoire and male age, philopatry and harem size. Syllables were organized in quite a large but still limited number of strophe types and variants, which were repeated by an individual male in the same or a relatively similar form within a season. Longitudinal analyses revealed significant effects of season and male age on strophe repertoire size. We also found a positive correlation between male harem size and strophe repertoire size. The composition of GRW strophe repertoire was stable within a season but significantly changed between years. At 3-year time intervals, GRW males exchanged more than half of their song types and almost all song variants. The level of between-year changes in song repertoire suggests that the GRW is a species adapted for learning

The Impact of Changes in Species Richness and Species Replacement on Patterns of Taxonomic Homogenization in the Carpathian Forest Ecosystems

The Carpathians are Eastern Europe’s largest contiguous forest ecosystem and a hotspot of biodiversity. However, not much is known about changes in species diversity in these forests. Here we investigate the long-time changes in the diversity of plant communities in the Eastern Carpathian beech forests. We also inquire about the similarity of plant communities between managed and protected forests. We conduct our analyses using not only the broad-sense measure of changes in β diversity (βsor) but also the measures that reveal whether the changes result from spatial turnover (βsim) or nestedness (βnes). Our study demonstrated that the mean species richness did not significantly change over time in both forest types. However, we found a significant decrease of species diversity in protected forests and the same trend, but on a smaller scale, in managed forests. In both forest types the decrease of species diversity was mainly caused by spatial turnover, while nestedness-related changes were relatively small. However, the direction of changes in βnes differed in managed and unmanaged forests in such a way that it reduced the decrease of species diversity in managed forests and amplified the decrease of species diversity in unmanaged forests. We discuss our findings in terms of biotic homogenization