Abstract: Presentation of a general pattern of migration is very difficult in the case of small passerines, especially nocturnal migrants, as the few accepted methods are inefficient here. It is difficult to follow migration visually (by visual field observations or moon watching). Classic ringing must be extremely intensive due to low or very low recovery rates, especially in Africa, Eastern Europe and Asia, which additionally rule out any reasonable estimation of the intensity of migration towards different destinations. Radar studies tell us nothing about the migration of individual species. Even the most modern methods, such as geolocation and radio tracking, are of very limited use for population studies. For these reasons, in most cases our knowledge in this area is fragmentary and insufficient for a satisfactory description of migration. In many cases only the breeding areas have been faunistically described in detail, while the winter-quarters and areas where the species is observed during migration are frequently described with less precision. The introduction of an effective method for studying local headings of migrants, using ‘orientation cages’, has made it possible to study the migration patterns of small passerine nocturnal migrants. The presented work is a case study on the migration pattern of the Blackcap, using data from orientation tests collected in autumn as part of the work of SEEN (SE European Bird Migration Network), consisting of 5,392 tests performed at 28 ringing sites in Central/Eastern Europe and the Middle East. The paper continues the discussion of the problem of applying the method to presentation of migration patterns in a geographically wide territory (Busse 2018, 2019, 2020).The hypothesis put forth by Busse (2019) that the arrival/departure heading axes are generally linear is accurate to within about one 10° sector was confirmed earlier. Here it was confirmed at the level of local patterns for the study sites. In general, the average deviation from the straight line is below 1°. However, there is some geographical variation, and this problem could be discussed when many more results of this kind become available for a few more species. Eight headings/streams of migrants are defined for the Blackcap within the area. Southward and south-eastern streams dominate in most of the study area. However, a very special, nearly longitudinal heading was found in southern Europe and the Middle East, which requires further study. Comparison of the patterns obtained from three different procedures strongly suggests that the general picture of Blackcap migration in Central/Eastern Europe and the Middle East is clear and coherent. Some variation in migration stream parameters (linearity and reversed heading share) suggests that further research in this direction should be conducted using data from other species. PubDate: Fri, 09 Dec 2022 00:00:00 GMT
Abstract: The introduction of an effective method for studying the local headings of migrants using ‘orientation cages’ has made it possible to study the migration patterns of small passerine nocturnal migrants. Numerous papers have been published on varied samples of local data collected using this method. A rough generalization was presented at the 2019 Meeting of the European Ornithologists Union and subsequently published in The Ring. Case studies on data collected for the Blackcap have already been published, and further studies on other species were suggested. The presented work is the next study of this kind, on the migration pattern of the Garden Warbler, using data from orientation tests collected in autumn as part of the work of the SEEN (SE European Bird Migration Network). The data comprises 2,593 tests performed at 31 ringing sites in Central/Eastern Europe and the Middle East. The paper continues the discussion of application of the method to present migration patterns in a geographically wide territory. The general data evaluation methods in this work are exactly as described in the earlier papers. The paper discusses azimuths of arrival and departure tracks at every ringing site, their linearity, number relations between departing and arriving headings, and the general pattern of migration streams followed by different groups of migrants.The hypothesis put forth earlier, stating that the arrival/departure heading axes shown in studies using orientation cages are situated linearly, is once again confirmed and can be used as a general assumption in this type of study. The average deviations are very small and are negligible for drawing general migration patterns. In some cases, however, there were deviations caused by the geographic location of the study site. This problem should be discussed in more detail when more species data become available. Nine migration streams are defined in the study area, which are presented, for simplicity, using different names and colours on maps. Southward and south-eastward streams are dominant and distributed similarly to the streams of the Blackcap. The most pronounced is a stream shown in yellow (YELLOW stream), which is directed from the wide area of central and eastern Europe to the Arabian Peninsula. The BLACK and NAVY streams are the most intriguing (running nearly longitudinally) and require a great deal of attention in further analyses of migration in the Mediterranean. Two styles of presentation of the species migration pattern are discussed, of which the location style of presentation seems to be more precise. The simpler presentation style that shows only general heading axes could be used to compare the general patterns of different species. PubDate: Fri, 09 Dec 2022 00:00:00 GMT
Abstract: Annual captures and biometric parameters of the Goldcrest (Regulus regulus) were studied at Tömörd, western Hungary. We used records of 4,284 individuals trapped and ringed between August and November within the study period (1998–2020). The Goldcrest was determined to be a regular partial migrant species with highly intensive migration in 2000, 2001, 2008, 2014 and 2019. The catching results showed very high number fluctuations at Tömörd, but the smoothed curves were distinctly wave-like in all age and sex classes. There were significant positive correlations between annual captures of age and sex classes. The average proportion of immature Goldcrests was 90%, the average proportion of male individuals was 63% and both proportions were stable between 1998 and 2020. There were similar decreasing trends in the average annual wing length and body mass of males and females from 1998 to 2020. This may indicate that the migration strategies of females may be modified by global climate change. PubDate: Fri, 09 Dec 2022 00:00:00 GMT
Abstract: Forests have an important role during migration. They act as ecological corridors and provide resting and feeding places for birds. In our study, we sought to determine whether migratory birds prefer secondary forest or canal vegetation during migration. The study was carried out in Southeast Hungary, in an oleaster forest and in a canal. We used 12 mist nets and the ringing method. The study period lasted from August to October 2016–2018, covering approximately the entire migration period. According to our results, the canal has a significant effect on the species assemblage, as it functions as a migration corridor during migration, most likely not only for diurnal migrants, but for nocturnal migrants as well. Our results showed that the presence of both woody and berry plants had some influence on the species composition. Interestingly, the presence of berries had a positive effect on the presence of insectivorous birds. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: The waterbird community structures of two sub-Himalayan wetlands (Nararthali and Rasomati) situated in forested areas were compared during the wintering period. These wetlands had similar geophysical features but were subject to different conservation efforts. Sixty species of waterbirds, including four globally threatened species, were recorded during the study. Nararthali was found to be more densely inhabited (116.05±22.69 ind./ha) by birds than Rasomati (76.55±26.47 ind./ha). Density increased by 44.6% at Nararthali and by 59% at Rasomati over the years of the study, from 2008 to 2015. Winter visitors increased considerably at Nararthali (66.2%), while a 71.1% decrease at Rasomati clearly indicated degradation of habitat quality at that site during the later years. Luxuriant growth of Eichhornia crassipes, siltation, poor maintenance and unregulated tourist activities were the key factors leading to the rapid degradation of Rasomati. Nararthali, on the other hand, a well-managed wetland habitat, showed an increasing trend in bird densities. Therefore, poor habitat management and rapid habitat alterations were observed to be the main reasons for depletion of bird density in the wetlands of eastern sub-Himalayan forest regions. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: One of the most effective methods of studying the migratory patterns of nocturnal passerine migrants is the use of orientation cages as a supplementary procedure at ringing sites. The most comprehensive studies using orientation cages (Busse’s Flat Orientation Cage) were conducted within the SEEN network (SE European Bird Migration Network), with more than 43,000 tests performed at more than 40 ringing sites in autumn. A number of papers were published based on these data, presenting an overall pattern of passerine migration over SE Europe-Middle East-NE Africa. For more detailed analyses, it was first necessary to solve some methodical problems within case studies. The current work presents details for discussion based on data from 1338 tests of Blackcaps performed during the years 1995–2010 at a single ringing station, Bukowo/Kopań, located on the Polish Baltic coast. The birds were tested according to the standard methodology of the SEEN network (Busse 2000). The problems investigated were (1) the repeatability of heading patterns obtained in different years, (2) the linearity of the estimated arrival and departure headings, and (3) quantitative aspects of the results in the description of the heading pattern when migratory groups are found.It was determined that (1) yearly heading patterns were generally coherent and could be analysed as uniform case data; (2-1) the hypothesis that the arrival/departure heading axes are generally linear is accurate to within about one 10° sector, at least in the case of the Blackcap. This is coherent with impressions from other known data sets, but does not mean that the rule always applies to all species at every location on the migration route. In the future, this problem should be studied on a more detailed scale. It was further established that (2-2) estimating arrival and departure headings makes it possible to define migratory groups (populations) passing the study site. The direct heading estimation procedure seems to be more sensitive in identifying migratory groups than the calculation procedure. Moreover, (3-1) the calculation procedure makes it possible to estimate some quantitative properties of headings of migratory groups and define some interesting, though preliminary, number patterns of local migratory patterns; (3-2) the number relations between birds demonstrating the arrival and departure headings of the migratory group seem to be an interesting parameter for study on the distance of migration of groups within a species and, possibly, between species. This is another interesting problem that cage tests could be used to solve in the future. Finally, (3-3) knowledge about trends of individual populations passing the defined site becomes accessible only using analysis of data from orientation cages. The estimated quantitative indices discussed above could be helpful in presenting the general migratory pattern of the species on a geographical scale. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: The Citrine Wagtail has been gradually expanding its breeding range from Asia westward into Europe since the middle of the last century. New breeding records of this species further to the west of Europe have emerged during the last several decades. The distribution of the Citrine Wagtail in Western Ukraine began at the end of the last century. A total of 48 Citrine Wagtails were ringed in August 1995–2016 at the Cholgynskyy ornithological reserve (West-Ukrainian Ornithological Station). The birds were recorded mainly in the first half of August, peaking from the beginning of the second decade to the middle of the month. At the beginning of August there were wagtails in different stages of moult. Adult moulted birds were recorded from the beginning of the second decade of August, while juvenile birds underwent partial moult during the first part of the month. The mean weight of adult moulted birds was higher than that of juveniles. At the beginning of August many Citrine Wagtails were lean, without fat reserves, with the mean fat class increasing by the end of the month. The autumn passage of M. citreola took place in W. Ukraine. Birds stay in the shallow waters, pastures, and reed beds to feed, overnight, moult and gain fat reserves for migration. PubDate: Thu, 31 Dec 2020 00:00:00 GMT
Abstract: The Wood Pigeon, Columba palumbus, is a common diurnal migrant across most of the Europe. The visual observations were carried out during autumn work of the Operation Baltic ringing stations, mainly at Mierzeja Wiślana (54°21’N, 19°19’E) parallely to the ringing of birds. Observations of passing birds were performed 15 minutes per every hour from sunrise to sunset. The autumn observation period was long enough to cover whole pigeons migration at the southern coast of Baltic (14 Aug. – 11 Nov.). Altogether 119,019 Wood Pigeons were observed within 20 seasons of observations. The goals of this work is (1) to describe the course of the Wood Pigeon autumn migration at the Polish Baltic coast as to numbers in long-term aspect and the seasonality of migration, (2) to propose further development in the study on wave structure of the bird passage. The main analysis of this work-description of the seasonal dynamics of migration - was carried out with modified and widened method used for that kind of analysis in earlier publications. In the present paper the wave structure is described by the estimated border days between supposed waves taking under consideration different properties of the passage dynamics. Here are used three groups of parameters: (1) total numbers of birds observed daily during several years, inter-year variability (as SD between year number values), and the coefficient of variation (V), (2) number of migration peaks that occurred in that date within years of the study (there were used two classes of peaks – High Peaks and Peaks), (3) numbers of birds passing during recognized peak days. All estimations were done independently of others and only finally summarized using common ranking scheme. Such step by step procedure make estimation more and more reliable. Very high agreement between estimations based on three groups of parameters suggests strongly that the proposed estimation procedure is effective enough. PubDate: Thu, 16 Jan 2020 00:00:00 GMT
Abstract: The general migration pattern of passerines can be estimated using a variety of methods. A number of partial analyses based on ringing data, usually limited to a few species, have been published. A very few continent-scale presentations have been offered, as extremely long periods of ringing activity are necessary for passerines. This is especially true for areas where the recovery rate is very low, including vast areas of north-eastern and eastern Europe and the Middle East/Africa. Similarly, radar and moon-watching studies are of limited value for drawing migration patterns within wider areas. Radar studies require good coverage by the radar systems, while weather radar distribution density and the level of evaluation are very uneven. Modern logger and satellite tracking are more applicable to non-passerines, and as yet enable detailed study only of limited numbers of individuals, and not population studies. At the end of the 20th century, a very simple tool was introduced for field studies on the preferred headings of individual birds caught for ringing, i.e. the use of flat orientation cages. This method was introduced as a standard within the SEEN (SE European Bird Migration Network) in 1995. This study presents a preliminary large-scale evaluation of the data collected within this project. The database used contains more than 43,000 orientation tests performed at 45 ringing sites. The area covered stretches from the northern part of western Russia to southern Egypt and from Italy and Poland to Siberia and Armenia. Eight streams of migration are identified within this area, creating a fairly complicated pattern of avian movements. PubDate: Thu, 16 Jan 2020 00:00:00 GMT
Abstract: Wind farms developing rapidly in order to meet the high demand for energy from green sources. However, the impact of wind farm operation on the environment still needs to be established. The risk to wild birds is drawing the attention of stakeholders and bird conservation organizations. Carcass search is the main method used to assess the impact of wind farm operation on wild birds of various systematic groups and sizes. Assessment of the overall risk that wind farms pose to birds depends primarily on accurate calculation of carcass removal times and the detection ability of the searcher.Most studies have assessed the carcass removal time using pet bird species, pigeons, or various local birds. In Egypt, all studies conducted in operating wind farms up to 2016 had used chickens to assess the carcass removal time and in this way to the estimate the total number of bird fatalities within wind farms.The use of birds killed by a wind farm in carcass removal trials provides the actual time of carcass disappearance, in contrast with the use of other bird species. The removal times of carcasses of parakeets, quails, partridges and chickens were shorter than those of carcasses of White Stork, White Pelican, Honey Buzzard, Black Kites and eagles used in the current study and in another study in Australia.The results of the present study indicate that carcasses of birds killed within the studied wind farm remain for two to three months, while the carcasses of other in species other localities remain no more than 1 to 15 days, which unquestionably influences the calculation of total fatalities and leads to overestimation of the overall risk that wind farms for birds. PubDate: Thu, 16 Jan 2020 00:00:00 GMT
Abstract: At the end of the 1980s, a relatively large data set was collected from orientation cage tests of nocturnal migrants caught in one locality in south-western Spain. It was published in The Auk in 1989. At the time of publication, the use of orientation cages was a major advance in detailed studies on passerine migration patterns. The basic evaluation procedure was to calculate the average vector of all numbers representing bird activity in a number of sectors of the full wind-rose and to use the Rayleigh test to determine the statistical significance of the distribution. However, due to hidden assumptions in the procedure used at that time, the resulting heading patterns could be called into question in light of further methodological development. The paper revisits the original set of orientation data collected in the last century in the reported study. The new results from the multimodal distribution accepting procedure are compared with the older pictures and are found to be much better at explaining the migration pattern there. In particular, the Garden Warbler and Reed Warbler, which were claimed to be ‘disoriented’, now show acceptable directionality patterns which do not differ in shape from those of other species. PubDate: Thu, 16 Jan 2020 00:00:00 GMT
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