Search Results

1 - 4 of 4 items

  • Author: János Török x
Clear All Modify Search

Summary

Different experiences from the past may have influence on individual’s behaviour through feedback mechanisms that can weaken or preserve the within-individual consistency of behavioural traits. Here, we aimed to find evidence for such feedback mechanisms that may operate on risk-taking behaviour via the effect of former experience to potential predation events in male Collared Flycatchers (Ficedula albicollis). We predicted that risk-taking of males would decrease after experiencing a predator’s attack in previous breeding seasons (negative feedback). We assessed risk-taking by flight initiation distance (FID) that is the distance at which an individual flees from an approaching predator, which was estimated for 234 individuals from different breeding seasons. Information on predation experience (i.e. occurrence of nest predation, the incidence of capture by human observers) was available from our long-term database on individual life histories. In a horizontal approach, we found no difference in FID when comparing males with former experience to predation with males naive to predators. A longitudinal approach relying on the repeated tests of the same individuals from different years yielded analogous results, we could not show a significant change in the risk-taking behaviour of the males as a consequence of experience to predation in past years. However, we found that individuals systematically took less risk over the years, which might be a consequence of acquiring general experience with age.

Abstract

During a twenty five days trip in Uganda a brief faunistic survey of birds, mammals and reptiles was performed. Altogether 380 bird species were observed in six National Parks and some other protected areas in the summer of 2012. From these 64 bird species are discussed here selected according the following criteria: rarity, occurrence in a new habitat or geographic area, and emergence of novel breeding phenological data of certain species. Our new records of House Sparrow (Passer domesticus) along the Kazinga Channel (between Lake Edward and Lake George) are outside the current distribution range of the species. The House sparrow expanded its area about 800 km toward west from their first record in Nairobi in 1992. Our new records on White-tailed Ant-thrush (Neocossyphus poensis), Red-tailed Ant-thrush (Neocossyphus rufus), Papyrus Yellow Warbler (Chloropeta gracilirostris), Shelley’s Rufous Sparrow (Passer shelley) and Streaky Seedeater (Serinus striolatus) also require the correction of distribution maps of this species in Uganda. In addition we give some remarks on the breeding phenology of Mountain Wagtail (Motacilla clara), Cassin’s Grey Flycatcher (Muscicapa cassini) and Northern Red Bishop (Euplectes franciscanus). Our recent observational data of African Skimmer (Rynchops flavirostris) may have importance for the Bonn Convention. These observations might be important from conservation and ecotouristic point of views

Abstract

In birds, individuals may show different behavioural and physiological responses when handling, and such variation may be related to individual differences in antipredator strategies. We performed a pilot study in both breeding and wintering populations of the Great Tit (Parus major), and we characterised three typical behavioural traits during a standard ringing procedure in captured birds. We assessed between- individual variations in breath rate, pecking rate and the number of distress calls displayed in response to handling, and also calculated the within-individual variation of these traits by repeated behavioural measurements. We found that these behaviours were consistently displayed within individuals (with repeatability varying between 0.44 and 0.82), and there was also some modest correlation between them (e.g. breath rate covaried with the number of distress calls). Furthermore, using multivariate linear models assessing a role of some potential predictors we found that a considerable amount of between-individual variation can be explained by sex and age differences and also by variation in body condition. However, the magnitude and direction of these relationships was inconsistent across seasons. Our results are in line with previous findings that several consistent behavioural traits measured during human handling could reflect individual specific antipredator strategy, but some confounding effects cannot be ruled out. Hence, our preliminary results require careful interpretation, and further studies are needed to assess the exact magnitude by which different behavioural traits are inter-related

Abstract

The haematocrit rate of the blood shows the individual physiological state. As the haematocrit grows, the higher erythrocyte number results in more efficient oxygen uptake capacity which can lead to better performance and probably a better survival rate of an individual. Hence we assume that the high value of haematocrit reflects good health state. Altogether 308 blood samples were collected from a wild population of Collared Flycatchers (Ficedula albicollis) in two breeding stages during a period of 2008-2010. We tried to elucidate the relationship between condition and haematocrit level of an individual and studied the haematocrit changes of an individual between years. The haematocrit values differed between years. Females had higher haematocrit values than males in 2010 but not in 2009. At courtship the haematocrit level of males was higher, than during nestling care. The different environmental effects and energy demands of the individuals may be the driving force behind the observed changes in haematocrit level. Analysing the changes between two years, there was a positive correlation between changes in condition index and haematocrit of individuals. The haematocrit values of an individual were repeatable between years. This finding suggests that haematocrit can be informative about the individual’s general health state.