1,720,965 research outputs found
Spatiotemporal distribution of Eurasian Spoonbills (Platalea leucorodia) outside the Carpathian Basin – the results of the Hungarian colour-ringing project based on twenty years (2003–2023)
Get PDFThe Eurasian Spoonbill (Platalea leucorodia) is a migratory waterbird. We used the confirmed
observations of colour-ringed individuals (2,735 specimens) of the Hungarian population collected outside the
Carpathian Basin between May 2003 and February 2023. 546 Spoonbills occurred in 28 countries. They used
mainly the Central Mediterranean Flyway, however, some individuals were seen along the East Atlantic Flyway
or the East Mediterranean Flyway. Three individuals were observed north of the Alps, too. A small proportion
of Spoonbills crossed the Sahara and they occurred in the Sahel zone, between Sudan in the east and Senegal
and Mauritania in the west. A few individuals were observed on Saharan wetlands in Algeria during winter. The
most important destination for the Hungarian (Pannonian) population during the migration is Tunisia, where
many of them spend the winter, primarily in the tidal area of the Gulf of Gabes. The first adults reached North
Africa (Tunisia) on 28 July during their southward migration, while the last ones stayed there until 23 April.
The first observation of juveniles in North Africa (Tunisia) happened on 31 August. Immature, 2- and 3-cy-
old birds spend the summer in unknown numbers in Tunisia. The majority of Pannonian Spoonbills migrate
through the Balkans and Italy and some stay there to winter, mainly in Italy. Some of the immatures spent the
summer in Italy. In southern Europe, the peak of the spring migration was in March, and the peak of the autumn
migration was in September. There was also a difference in the migration of different age groups: in Southern
Europe, the migration peak of adult birds falls between March and April, while most of the immatures were
observed in May and June during northward migration. The peak of the southward migration in all age groups
was observed in September. In the southern part of Europe, there may still be adults migrating north on 13
May, while other adults may already migrate southward on 15 May. The earliest juvenile migrating south was
documented on 30 June in Italy
Dispersal and migration of Spoonbills (Platalea leucorodia) ringed in Hungary
No full textKIVONAT: Meghatároztam a kanalasgémek fő vonulási útvonalát, ami az Adriai vonulási
útvonalon helyezkedik el, és a Nyugat-Balkánon, illetve Olaszországon keresztül elsősorban
Tunéziába, vagy Olaszország déli részére vezet. Innen egyes madarak továbbvonulnak, és a
Szaharán túli területekre, így Nigerbe, Nigériába és Maliba jutnak. A madarak egy kisebb
hányada Görögországból, Törökországból, Izraelből és a Nílus mellől került elő, mely a
Kelet-Mediterrán vonulási út használatát feltételezi, míg a Marokkón keresztül Maurutániába
jutó madarak a Kelet-Atlanti vonulási útvonalhoz csatlakoztak. A vonulási útvonalon
meghatároztam azokat az állomásokat, melyek lényegesek a kanalasgémek pihenése és a
zsírtartalékok feltöltése szempontjából.
A több mint 100 éves adatsor elemzésekor a fenológiában bekövetkező szignifikáns
változást nem tudtam kimutatni, ami a régi fémgyűrűzési adatok kis számára, és
pontatlanságára vezethető vissza. Nem szignifikáns trendként viszont kijelenthető, hogy a
kanalasgémek korábban érkeznek vissza a költőhelyükre napjainkban, mint közel száz évvel
ezelőtt, ugyanakkor az elvonulás időzítésében nem találtam különbséget. Szignifikáns
különbség mutatkozott abban, hogy az egyes korcsoportok mikor érkeznek vissza
Magyarországra: az öreg, fészkelő madarak térnek vissza először, míg legkésőbb az immatur,
nem költő madarak.
A több mint 100 éves adatok elemzésével jelentős változást mutattam ki a vonulással
kapcsolatban. 1964 előtt a kanalasgémek jelentős része vonult délkelet felé, és ezek a madarak
a Nílust korridorként használva vonultak a Szaharán át. Később ez a vonulási irány kisebb
jelentőségű lett adataim szerint, de a madarak még mindig használják. Nem sikerült pontosan
tisztázni, hogy mi okozhatta ezt a változást: lehetséges, hogy a Nílusra megépített Asszuánigát
gyakorolt negatív hatást a Nílus ökológiai rendszerére. A délkeleti útvonal hosszabb, mint
a dél-nyugati, így a hosszabb út kapcsán több negatív hatás érheti a madarakat, mely
pusztuláshoz, vagy kisebb szaporodási sikerhez vezetett, és ez is okozhatta a délkelet felé
vonuló madarak számának visszaesését. Nem zárható ki az sem, hogy újabban hiányoznak a
területről a megfigyelők. A délnyugat felé vezető út ugyanakkor szignifikánsan rövidebb a
délkeletinél, és itt a Gabesi-öböl kiterjedt ár-apály zónája a kanalasgémeknek megfelelő
táplálkozó-területet biztosít. Adataim alapján úgy tűnik, hogy ennek a területnek a jelentősége
nőtt, ami részben amiatt lehet, hogy régebben a területet nem vizsgálták, így sem a
kanalasgémekről, sem más madárfajokról nem érkezett innen adat. Továbbá a délnyugati
útvonalon a Szaharában nincs korridor, így feltételezhetően a sivatag, mint barrier sok
madarat megállásra kényszerít. Ugyanakkor kis számban vannak kanalasgémek, melyek
nekivágnak a Szaharának, és a Száhel vizes élőhelyeire jutnak. A Szaharán túli vonulás még
valószínűleg a régi, „vizes Szahara” időszakából maradhatott vissza, amikor a Szaharát még
behálózták a folyók, és a tavak. A Szahara kiszáradásával ez a hosszú út egyre több
kockázatot rejtett magában, ami részben a madarak pusztulásához, részben alacsonyabb
költési sikeréhez vezetett. Ennek, és a mediterrán térség északi részén tapasztalható egyre
enyhébb klíma következtében a kanalasgémek a Földközi-tenger térségében megfelelőbb
vizes élőhelyeket találhattak az áttelelésre, ami rövidebb vonulási útvonalat is jelentett,
másrészt pedig megkímélte a madarakat a kockázatos sivatagi átkeléstől. A száz éves adatsor
elemzése kimutatta, hogy jelenleg a kanalasgémek rövidebb távolságra vonulnak Afrikában,
mint korábban. Valószínű, hogy azok a folyamatok, melyek jelenleg a holland populációban
zajlanak, oda vezetnek, ahová a közép-európai populáció már korábban jutott az erősebb
szelekciós nyomás hatására, vagyis a Szaharán való átkelés helyett az attól északabbra lévő
telelőhelyek jelentősége várhatóan nőni fog. Összehasonlítva a magyar és a holland
populációt, a magyar gyűrűs madarak döntő többsége rövidtávú vonuló, míg a holland gyűrűs
madarak nagyobbik hányada hosszútávú vonuló. A klíma enyhülésével a fiatal, magyar gyűrűs
kanalasgémek sikeresen áttelelnek a Kárpát-medencében is, illetve az áttelelési kísérletek
gyakorisága emelkedett.
Elemeztem a magyar gyűrűs kanalasgémek diszperzióját a Kárpát-medencében.
Megállapítottam, hogy a Kárpát-medencében a kanalasgémek fészkelési időben ragaszkodnak
a születési helyükhöz, de jelentős azoknak a madaraknak a száma, melyek a születési helyük
100 km-es körzetén kívülre diszpergálnak. Ez az érték magasabb, mint a tengerpartok
torkolatvidékén, vagy ár-apály zónájában fészkelő kanalasgém-populációknál jellemző.
Hasonlóan, a kirepülést követő kóborlás során a kontinentális körülmények között a fiatal
madarak nagyobb mértékben diszpergálnak, mint a tengerparti madarak. Továbbá kimutattam,
hogy a fiatal kanalasgémek diszperziója nincs irányhoz kötve, az a Kárpát-medencében
irányfüggetlenül zajlik.
Adataim azt mutatják, hogy az immatur madarak valószínűleg több stratégiát
alkalmaznak a faj fészkelési idejében. Az egyik stratégia az átnyaralás a telelőterületen, mely
mérsékli a vonulás kockázatait. Egy másik stratégia szerint a kanalasgémek elvonulnak a
telelőhelyükről, de nem mennek a fészkelőhelyekre. Ennek során az egyedek feltehetően a
vonulási útvonalról, a rajta található táplálkozási lehetőségekről szereznek információkat,
mely tapasztalatot öreg madárként valószínűleg jól tudnak majd hasznosítani. A harmadik
stratégia a visszatérés a fészkelőhelyre, ahol a vonulás útvonala mellett a későbbi
fészkelőhelyről is tapasztalatot, információt szerezhet az adott egyed.
Bemutattam, hogy a vonulás időzítésében, és a fészkelőhely kiválasztásában
valószínűleg szerepet játszik a vizes élőhelyek állapota.
A rendelkezésre álló adatok alapján a kanalasgémek a globális változásra, így mind a
klímaváltozásra, mind az ember tájátalakító hatására különösen érzékenyek lehetnek, mivel a
leginkább sérülékeny, sekély vizű vizes élőhelyekhez kötődnek, azok specialista madarai. Így
nemcsak a fészkelőhelyen, hanem a vonulási útvonalon, és a telelőhelyeken is szükséges, és
lényeges a vizes élőhelyek védelme, rekonstrukciója, és a természetes állapotok megőrzése.ABSTRACT: I have identified the major migration route located in the Adriatic flyway
which leads primarily from the Carpathian Basin to Tunisia or South-Italy across the western
part of the Balkan Peninsula and Italy. Individual birds migrate further from this region to
sub-Saharan Africa, including Niger, Nigeria and Mali. Smaller proportion of Spoonbills are
found in Greece, Turkey, Israel or along the Nile Valley suggesting the use of the East-
Mediterranean Flyway. However, Spoonbills migrating to Mauritania cross Morocco join the
East-Atlantic Flyway.
I have identified the stop-over sites used by Spoonbills along the Adriatic Flyway.
These stop-over sites are important because of their role in replenishing fat reserves and as
roost sites.
During the analyses of the dataset spanning more than 100 years, I was not able to
detect significant changes in phenology, which is probably due to the small number and less
accurateness of historical metal ringing records. However, based on non-significant trends, I
have found that Spoonbills arrive sooner in breeding sites nowadays than 100 years ago. In
contrast, I have found no changes in the timing of departures. Significant differences were
detected between the timing of arrivals of age groups: adult breeding Spoonbills return first,
while immature, non-breeding individuals are the latest.
By analysing data spanning more than 100 years I detected significant changes in
migration patterns. Prior to 1964, a substantial part of Spoonbills migrated south-east using
the Nile Valley as a corridor across the Sahara. Later, this migration direction became less
significant which are still used by the birds. I was not able to identify the factors driving this
change: it is conceivable that the Aswan High Dam built on the Nile negatively affected the
ecological system of the river. As the south-eastern flyway is longer than the south-western
route, covering longer migration distances might lead to more negative effects causing higher
rates of mortality of decreased breeding success which might have resulted in the decline of
Spoonbills migrating to south-east. Further, it cannot be excluded that observers are lacking
from the area nowadays. The south-western flyway is significantly shorter than the southeastern
route where the extensive tidal zone of Gulf of Gabes provides suitable feeding areas
for Spoonbills. Our records suggest that the significance of this area has increased, which is
partly explained by the lack of surveys in former times and thus the lack of data on Spoonbills
and other birds. Further, the south-western route lacks the corridor across the Sahara, thus the
desert serves as a barrier for many birds. However, small numbers of Spoonbills try to cross
the Sahara and arrive in the wetlands of the Sahel zone. Migration over the Sahara is probably
a relict flyway dating to the 'wet Sahara' period when the desert was interspersed by rivers and
lakes. Following the desiccation of the Sahara, covering this longer way was implicated by an
increasing number of risks which has partly led to increasing mortality and to declining
breeding success. As a result of this process and because of the milder climates in the north,
Spoonbills found suitable overwintering areas in the Mediterranean which implied a shorter
migration route and saved the birds from the risky crossing of the Sahara. The analysis of the
records spanning hundred years showed that Spoonbills migrate to smaller distances in Africa
than formerly. Probably the processes recently observed in the Dutch population has formerly
been active in the Central-European population as a result of selection pressures: instead of
crossing the Sahara, the significance of more northerly wintering grounds is expected to
increase. Comparing the Hungarian and the Dutch populations, majority of Hungarian birds
are short-distance migrants while the dominant part of the Dutch Spoonbills are long-distance
migrants. Following the mild climatic trends, Hungarian young ringed individuals
successfully overwinter in the Carpathian Basin with the increasing frequency of
overwintering attempts.
I have analysed the dispersion of Hungarian ringed Spoonbills in the Carpathian
Basin. I have concluded that Spoonbills show fidelity to natal sites during the breeding period.
However, the number of birds dispersing in a range of 100 kilometres around their natal
colony is significant. This value is higher than those measured in Spoonbill colonies located
in estuaries or tidal zones. Likewise, young birds disperse to a larger extent than coastal birds
during vagrancy after fledging under continental conditions. Further, I have demonstrated that
the dispersion of young Spoonbills is not direction-dependent within the Carpathian Basin.
My data show that immature birds probably use several strategies during breeding.
One of the strategies include oversummering in wintering grounds which decreases the risks
of migration. The alternative strategy involves migration from wintering grounds to nonbreeding
areas. During this movement Spoonbills collect information on migratory routes and
food availabilities which can be used later as adult birds. The third strategy includes a return
to breeding ground, where individuals might obtain information on later breeding sites besides
discovering novel flyways.
I have demonstrated that the quality of wetlands probably play a role in the timing of
migration and nest site selection. Based on the data available, Spoonbills might be especially
sensitive to global change including climate change as well as human land use changes, as
they are closely connected to wetlands. Therefore protection, reconstruction of wetlands and
preservation of their natural condition is important not only on the breeding grounds but also
along migratory flyways and wintering areas
Winter distribution and migratory strategies of Eurasian Spoonbills (Platalea leucorodia) from the Pannonian breeding population: are they long-distance migrants?
Get PDFIn this paper, the wintering characteristics of the Eurasian Spoonbills (Platalea leucorodia) breeding in the Carpathian Basin (Pannonian population) were analysed. The data of 305 wintering Spoonbills marked with colour-rings in Hungary was used. A significant part, 80% of the Spoonbills, wintered in Africa, while 20% spent the winter in Europe and only two birds in the Asian part of western Turkey. The most important wintering sites were in the central part of North Africa (in Algeria, Libya, but mainly Tunisia) and Italy. The tidal area in the Gulf of Gabes in Tunisia was the most important area where a significant proportion, 65% of all wintering Spoonbills, spent the winter. This study provided new evidence of Spoonbills occurring in Saharan wetlands (Chott Tindla in Algeria) in winter. 2% of the resighted Spoonbills were reported from the wetlands of the Sahel in Sudan, Nigeria, Niger, Mali, Mauritania, and Senegal. European winterers were mainly found in Italy and, to a lesser extent, in the Balkans and the Carpathian Basin. The mean distance between the natal colonies and the wintering areas was 1,535 km. Spoonbills migrated in a south-southwestern direction (mean: 213°) to reach their wintering sites. In the Hungarian population, most specimens (94%) were short-distance migrants (wintered north of 22°N), 2% were long-distance migrants, and 4% were residents. However, the proportions of the residents and short-distance migrants are supposed to be overestimated and the proportion of the long-distance migrants is likely to be underestimated due to the lack of observation effort in sub-Saharan Africa. However, based on the winter census data and the proportion of ringed individuals of Hungarian origin in the wintering flocks, I estimated that the lack of observation effort would only slightly modify the result. There were two shifts in migratory strategies on an individual level: a resident Spoonbill became a short-distance migrant, and a short-distance migrant became a long-distance migrant by a following winter. While most of the East Atlantic Spoonbills are long-distance migrants, the results of this study indicate that most birds in the Pannonian population are likely to be rather short-distance migrants. The results of the GPS tracking also confirm that most Pannonian Spoonbills are short-distance migrants and support the main conclusion of this paper
Observations on parental care of the Eurasian Spoonbill (Platalea leucorodia) during the post-fledging dispersal
No full textThe number of available publications on the post-fledging parental care of wading birds (herons, ibises, spoonbills, and storks) and many other bird species is limited. In this study, I summarised the available knowledge collated from the observations of the Eurasian Spoonbills (Platalea leucorodia) in Hungary. A part of the available data is based on observations of colour-ringed individuals. The latest feeding event of a young by its parent was observed at Lake Csaj on 5 October 2020. The youngsters were being fed by their parents for 43 days (observed maximum) during the post-fledging dispersal. However, I estimated that this behaviour could even last for as long as 53 days. The parents lead (care for) their yearlings for 51 days (observed maximum), again I estimated that it could potentially last for a longer period of 63 days. The estimated length of parental care and feeding period could be longer or a little bit shorter during the post-fledging dispersal because it was not possible to follow the life of the families exactly. During parental care (feeding and leading of chicks), the majority of the colour-ringed Spoonbills were observed 2–26 km to the natal colonies of yearlings and the breeding colonies of the adults. However, on some occasions, they were 111–145 km far from those colonies. During the post-fledging dispersal, Spoonbills care for their chicks for a longer time than the European breeding heron species. A possible reason could be that the bills of young Spoonbills are not appropriate for fishing effectively at the beginning of fledging because of their shorter length and their less efficient hydrodynamic effect during lateral sweeping. Another reason could be that Spoonbills are tactile foragers and need more time to learn fishing. Based on data of a juvenile followed by a GPS device, learning the migration route and stop-over sites from parents or experienced adults could be important for Spoonbills, otherwise, young migrating alone with no accomplished individuals may not find the optimal routes and the proper stop-over areas. In the case of Spoonbills, we still do not know exactly the features of parental care during the post-fledging dispersal and have even less data on it during the migration. Thus, I request potential observers along the Adriatic Flyway to record the observations of parent-offspring interactions (feeding by parents, begging) particularly the Hungarian colour-ringed adults and/or young individuals and send data to the author’s e-mail address
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispersal and migration of a specialist waterbird: where do Eurasian Spoonbills (Platalea leucorodia) come to Hungary from?
No full textAbstract
Between 1950 and 2016, 254 individuals of Eurasian Spoonbill (Platalea leucorodia) of foreign origin were observed during their dispersal or migration in Hungary from eight countries. Colour-ringed birds originating from Serbia, Croatia and the Czech Republic were the most commonly observed, while individuals from Italy, the Danube Delta (Romania) and the Wadden Sea area (Denmark and The Netherlands) were observed rarely in Hungary. Only metal ringed Spoonbills were recovered from Austria. All age-classes were found in Hungary: juveniles were the most common, while 2cy immatures formed the rarest class. Adults from the Wadden Sea area, and also from the Danube Delta were observed in Hungary during the breeding season, implying potential gene flow between those areas and the Carpathian Basin. My results predict that the breeding population of the Carpathian Basin forms a unique subunit of a metapopulation which is in close contact with the Czech population. The nesting of adults of Serbian and Croatian origin was confirmed in Hungary. Two prospecting subadults (4cy) were observed in Hungarian colonies, one was from Serbia, and the other was from Italy. One adult (5cy) occurred in several Hungarian wetlands in a short period before breeding, which probably explored habitats for breeding or for feeding. Spoonbills of Czech, Serbian, Croatian and Italian origin observed in Hungary used the Central Mediterranean or the Adriatic Flyway. Individuals from the East Atlantic population arrived to Hungary by shifting their migration routes. One bird from the Danube Delta wintered in Tunisia, where it probably joined Hungarian breeders and reached Hungary with them. Adults and juveniles from the Czech Republic used the wetlands around Lake Neusiedler as a stop-over and staging area during autumn migration. My results suggest that Hungarian wetlands play an important role in the movements and breeding of Spoonbills in Central Europe, thus, the management and conservation of these wetlands are essential for the future.</jats:p
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
