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  • Author: Péter Fehérvári x
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Abstract

Shortage of breeding sites is an important limiting factor of bird populations. Artificial breeding platforms, nest-boxes or man-made twig nests often present solutions with remarkable results, however long-term sustainability of these populations remains to be resolved. Furthermore, the question whether the inference of results of studies conducted on birds breeding in artificial breeding sites can be generalized to other populations, still remains open. Here we present the history, and the results of a 20 year old (1995-2015) nest-box programme initiated to increase potential breeding possibilities of Red-footed Falcons in an area, where nest-site shortage was a severe limiting factor. We show how various other species (Jackdaws, Kestrels and Long-eared Owls) have utilized these resources, and present descriptive statistics on their reproductive performance. Analysing the data of a total of 1432 breeding attempts, we show that Red-footed Falcons have similar clutch sizes, and nesting success (i.e. ratio of nests with at least on fledgling), however fledging success (ratio of the number of eggs/fledged nestlings) was different in artificial nest-boxes. When we excluded closed box types from artificial nests, this difference was not apparent. In case of Kestrels (n=1626 breeding attempts) clutch size was significantly higher in artificial nests, while we found no difference in fledging or nesting success. When only comparing open boxes to natural nests, the difference in clutch size was no longer significant. We also analysed the effect of nest box design on reproductive parameters of the two species using regression trees. Inter annual effects were the most important in shaping clutch size and fledging rate of both falcon species, however we also found nest-box design effects, but only in Red-footed Falcons. In years when mean clutch size was high, these birds had lower clutch size in an older, darker nest-box type compared to an alternative design, and to open boxes. However, fledging rate in the same years was lower for both open boxes and older nest-boxes. We conclude that artificial colonies are an important and successful tool in Red-footed Falcon conservation, and that the breeding parameters measured in artificial colonies depend on nest-box design. We present correlative evidence that closed boxes have a significant positive species specific effect on reproduction, probably due to their protection against weather. We also show that birds may have a preference for a certain nest-box design, and that the breeding success in the less favoured box type may be similar to that in open nests. We recommend that future studies incorporate nest-type and nest-box design effects in all comparisons made on reproductive performance in case of Red-footed Falcons and Kestrels.

Abstract

Ornithological studies often rely on long-term bird ringing data sets as sources of information. However, basic descriptive statistics of raw data are rarely provided. In order to fill this gap, here we present the seventh item of a series of exploratory analyses of migration timing and body size measurements of the most frequent Passerine species at a ringing station located in Central Hungary (1984–2017). First, we give a concise description of foreign ring recoveries of the Thrush Nightingale in relation to Hungary. We then shift focus to data of 1138 ringed and 547 recaptured individuals with 1557 recaptures (several years recaptures in 76 individuals) derived from the ringing station, where birds have been trapped, handled and ringed with standardized methodology since 1984. Timing is described through annual and daily capture and recapture frequencies and their descriptive statistics. We show annual mean arrival dates within the study period and present the cumulative distributions of first captures with stopover durations. We present the distributions of wing, third primary, tail length and body mass, and the annual means of these variables. Furthermore, we show the distributions of individual fat and muscle scores, and the distributions of body mass within each fat score category. We present data only for the autumn migratory period since there were only 27 spring captures in the study period. We distinguish the age groups (i.e. juveniles and adults) in the analyses. Our aim is to provide a comprehensive overview of the analysed variables. However, we do not aim to interpret the obtained results, merely to draw attention to interesting patterns that may be worth exploring in detail. Data used here are available upon request for further analyses.

Abstract

Active conservation measures often entail supplementing scarce resources, such as food or nesting site to high conservation value species. We hypothesized that adequate nest material in reasonable distance is a scarce resource for Rooks breeding in open grassland habitats of Hungary. Here we show that Rooks willingly utilize large quantities of provided excess nesting material, and that this procedure may alter nest composition, and increase the number of successful pairs. Our results show that while nest height remains constant, twig diameter is significantly larger, the number of twigs used per nest is presumably smaller, and that the ratio of nests with fledglings is higher in a rookery where supplementary twigs were present. Providing twigs and branches in the vicinity of rookeries may serve as an active conservation measure to increase the number of nests in a rookery, and thus the potential number of nesting possibilities for Red-footed Falcons.

Abstract

This paper is the third part of our bird ringing data analysis series (Harnos et al. 2015a, 2016a) in which we continue to focus on exploring data using the R statistical environment. Here, we give a short description of missing data patterns, then handling and visualization techniques that help simultaneously explore the data and the structure of missing values. We try to emphasize that missing data can seriously distort the results of the analyses, therefore the conclusions drawn.

Abstract

This paper is the second part of our bird ringing data analyses series (Harnos et al. 2015a) in which we continue to focus on exploring data using the R software. We give a short description of data distributions and the measures of data spread and explain how to obtain basic descriptive statistics. We show how to detect and select one and two dimensional outliers and explain how to treat these in case of avian ringing data.

Abstract

Bird ringing datasets constitute possibly the largest source of temporal and spatial information on vertebrate taxa available on the globe. Initially, the method was invented to understand avian migration patterns. However, data deriving from bird ringing has been used in an array of other disciplines including population monitoring, changes in demography, conservation management and to study the effects of climate change to name a few. Despite the widespread usage and importance, there are no guidelines available specifically describing the practice of data management, preparation and analyses of ringing datasets. Here, we present the first of a series of comprehensive tutorials that may help fill this gap. We describe in detail and through a real-life example the intricacies of data cleaning and how to create a data table ready for analyses from raw ringing data in the R software environment. Moreover, we created and present here the R package; ringR, designed to carry out various specific tasks and plots related to bird ringing data. Most methods described here can also be applied to a wide range of capture-recapture type data based on individual marking, regardless to taxa or research question.

Abstract

The Red-footed Falcon is a facultatively colonial species that exploits rookeries, artificial nest-box colonies and solitary corvid nests for breeding. Moreover, the remain gregarious in the post breeding period using communal roost sites prior to migration. We developed and implemented a survey protocol to allow to precisely estimate the number of breeding pairs in all three breeding types and to assess large scale spatio-temporal changes in roost site usage. Our results show that the lowest number of breeding pairs (558) was in 2006. However, in 2014 the number of pairs showed a two fold increase, mainly due to a large scale nest-box programme implemented in the past decade. We identified a total of 105 roost sites throughout the country. The number of birds peaked in the second week of September in the past 10 years. We formulate a recommendation to maintain population monitoring efficiency by reducing the frequency of full surveys to 5 years and using designated study areas to control for temporal trends in between.

Abstract

Ornithological studies often rely on long-term bird ringing data sets as sources of information. However, basic descriptive statistics of raw data are rarely provided. In order to fill this gap, here we present the sixth item of a series of exploratory analyses of migration timing and body size measurements of the most frequent passerine species at a ringing station located in Central Hungary (1984–2017). First, we give a concise description of foreign ring recoveries of the European Robin in relation to Hungary. We then shift focus to data of 40,128 ringed and 11,231 recaptured individuals with 24,056 recaptures (several years recaptures in 313 individuals) derived from the ringing station, where birds have been trapped, handled and ringed with standardized methodology since 1984. Timing is described through annual and daily capture and recapture frequencies and their descriptive statistics. We show annual mean arrival dates within the study period and present the cumulative distributions of first captures with stopover durations. We present the distributions of wing, third primary, tail length and body mass, and the annual means of these variables. Furthermore, we show the distributions of individual fat and muscle scores, and the distributions of body mass within each fat score category.We distinguish the spring and autumn migratory periods and age groups (i.e. juveniles and adults). Our aim is to provide a comprehensive overview of the analysed variables. However, we do not aim to interpret the obtained results, merely to draw attention to interesting patterns that may be worth exploring in detail. Data used here are available upon request for further analyses.

Abstract

Ornithological studies often rely on long-term bird ringing data sets as sources of information. However, basic descriptive statistics of raw data are rarely provided. In order to fill this gap, here we present the fifth item of a series of exploratory analyses of migration timing and body size measurements of the most frequent Passerine species at a ringing station located in Central Hungary (1984–2016). First, we give a concise description of foreign ring recoveries of the Common Nightingale in relation to Hungary. We then shift focus to data of 3892 ringed and 1499 recaptured individuals derived from the ringing station, where birds have been trapped, handled and ringed with standardized methodology since 1984. Timing is described through annual and daily capture and recapture frequencies and their descriptive statistics. We show annual mean arrival dates within the study period and present the cumulative distributions of first captures with stopover durations. We present the distributions of wing, third primary, tail length and body mass, and the annual means of these variables. Furthermore, we show the distributions of individual fat and muscle scores, and the distributions of body mass within each fat score category. We distinguish the spring and autumn migratory periods and breeding season and age groups (i.e. juveniles and adults). Our aim is to provide a comprehensive overview of the analysed variables. However, we do not aim to interpret the obtained results, merely to draw attention to interesting patterns that may be worth exploring in detail. Data used here are available upon request for further analyses.

Abstract

Ornithological studies often rely on long-term bird ringing data sets as sources of information. However, basic descriptive statistics of raw data are rarely provided. In order to fill this gap, here we present the fourth item of a series of exploratory analyses of migration timing and body size measurements of the most frequent Passerine species at a ringing station located in Central Hungary (1984-2016). First, we give a concise description of foreign ring recoveries of the Common Blackbird in relation to Hungary. We then shift focus to data of 6849 ringed individuals and 6081 recaptures derived from the ringing station, where birds have been trapped, handled and ringed with standardized methodology since 1984. Timing is described through annual and daily capture and recapture frequencies and their descriptive statistics. We show annual mean arrival dates within the study period and present the cumulative distributions of first captures with stopover durations. We present the distributions of wing, third primary, tail length and body mass, and the annual means of these variables. Furthermore, we show the distributions of individual fat and muscle scores, and the distributions of body mass within each fat score category. We distinguish the spring and autumn migratory periods, breeding and wintering seasons, ages (i.e. juveniles and adults) and the two sexes. Our aim is to provide a comprehensive overview of the analysed variables. However, we do not aim to interpret the obtained results, merely to draw attention to interesting patterns that may be worth exploring in detail. Data used here are available upon request for further analyses.