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Jarosław Nowakowski and Jacek Chruściel

Speed of autumn migration of the Blue Tit (Parus caeruleus) along the eastern and southern Baltic coast

An analysis of the speed of autumn migration was based on 315 ringing recoveries of Blue Tits caught between 1963-1999 at 6 ringing stations along the south-eastern and southern Baltic coast. It was found that among passerines the Blue Tit is the slowest European migrant (median value - 25.8 km/day, average - 28.4 km/day), with a very low (intra- and interpopulation) variation of migration speed. No differences in migration speed were found between individuals of different age and sex and among years of different intensities of movements. The migration speeds of the Blue Tit and the Great Tit (Parus major) in different years correlated.

Open access

Jarosław Nowakowski and Jacek Chruściel

An Index to Estimate the Wing Area in A Small Passerine, Using the Blue Tit (Cyanistes caeruleus) As A Case Study

In this paper we suggest two new indices that can be used to estimate passerines' wing area. The first is a simplified index that considers wing pointedness and the width of each primary, the second is an extended index that also considers the length of the forearm. Using the Blue Tit as an example, we show that the sum of the width of all remiges is correlated with the maximum length of the folded wing (rp = 0.42, p = 0.020, N = 30). The length of the ulna is correlated with the maximum length of the folded wing (rp = 0.56, p = 0.005, N = 24). The two indices were derived from measurements of the wing length and the wing formula of birds caught at ringing stations. The indices can be used to analyse materials the stations have collected over the past 50 years. We also discuss how these indices can be applied in intra- and interspecific comparisons and to data collected using different standard methods.

Open access

Jarosław Nowakowski, Jacek Chruściel, Małgorzata Ginter and Katarzyna Rosińska

Any change in the Methodology of field studies on bird Migration? A comparison of methods used in 1994-2003 and a Quarter Century earlier

The holistic approach to the study of bird migration observed in the past decades and the huge advancement in technology should be seen in the numbers and types of methods used in field studies for this phenomenon. To check this assumption, we compared field methods used in the studies on bird migration published in international journals in 1994-2003 (N = 570 papers) and in 1967-1976 (N = 394 papers). We noted an increase in the mean number of methods per a single paper (from 1.49 in the former of these decades to 1.98 in the latter) and a change in the frequency of each method. In recent years, methods such as satellite telemetry, DNA or isotope proportions analyses have been developed. An increase in the mean number of methods as well as changes of the most frequently used methods were more apparent in journals indexed on the ISI Master Journal List in 2003 than in other current journals, where the methods were often found to be similar to those applied a quarter century earlier, which surprised us.

Open access

Jarosław K. Nowakowski, Jacek Chruściel and Krzysztof Muś

Abstract

Nowakowski J.K., Chruściel J., Muś K.: Does mist-netting provide reliable data to determine the sex and age ratios of migrating birds? A case study involving the Great Tit (Parus major) and the Blue Tit (Cyanistes caeruleus). Ekologia (Bratislava), Vol. 32, No. 2, p. 173-185 , 2013.

Ringing results of tits caught at two stations on the Polish Baltic coast were used to check if mistnetting could be successfully used to analyse the composition of sex and age classes of migrating birds. Four hypotheses are discussed, describing the distribution of age and sex classes during migration, and the consequences these distributions might have for the catching results. We analysed records of 59 000 Blue Tits and more than 84 000 Great Tits that were caught and we found a similarity in the results of catches at stations 188 km apart, and a higher similarity among catching sites 0.5-16 km apart. These results proved that mist-netting provides reliable data on the sex and age structure of migrating flocks, and that these data can generally be interpreted as representative for at least the area in a radius of more than 10 km. The results also showed a migratory divide through the central part of the Polish Baltic coastline between irruptive Blue Tits in the west and regular partial migrants in the east. Great Tits showed no tendency for irruptions anywhere in the study area. A high correspondence in the age and sex ratio was found for Great Tits and Blue Tits, in particular where both species are regular migrants. We found that the ratios of females and immatures did not differ by more than 1% over many years of study in these areas.