Antikythira Bird Observatory

Athens, Greece

Antikythira Bird Observatory

Athens, Greece
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Fransson T.,Swedish Museum of Natural History | Karlsson M.,University of Stockholm | Kullberg C.,University of Stockholm | Stach R.,University of Stockholm | And 2 more authors.
Journal of Avian Biology | Year: 2017

Migratory birds wintering in Africa face the challenge of passing the Sahara desert with few opportunities to forage. During spring migration birds thus arrive in the Mediterranean area with very low energy reserves after crossing the desert. Since early arrival to the breeding grounds often is of importance to maximize reproductive success, finding stopover sites with good refuelling possibilities after the Saharan passage is of utmost importance. Here we report on extensive fuelling in the great reed warbler Acrocephalus arundinaceus on the south coast of Crete in spring, the first land that they encounter after crossing the Sahara desert and the Mediterranean Sea in this area. Birds were studied at a river mouth and due to an exceptional high recapture rate (45 and 51% in two successive years), we were able to get information about stopover behaviour in 56 individual great reed warblers during two spring seasons. The large proportion of trapped great reed warbler compared to other species and the large number of recaptures suggest that great reed warblers actively choose this area for stopover. They stayed on average 3–4 d, increased on average about 3.5 g in body mass and the average rate of body mass increase was 4.8% of lean body mass d–1. Wing length affected the rate of increase and indicated that females have a slower increase than males. The results found show that great reed warblers at this site regularly deposit larger fuel loads than needed for one continued flight stage. The low body mass found in great reed warblers (also in birds with high fat scores) is a strong indication that birds staging at Anapodaris still had not been able to rebuild their structural tissue after the strenuous Sahara crossing, suggesting that rebuilding structural tissue may take longer time than previously thought. © 2016 The Authors

Bounas A.,University of Ioannina | Evangelidis A.,Antikythira Bird Observatory | Sotiropoulos K.,University of Ioannina | Barboutis C.,Antikythira Bird Observatory
Acrocephalus | Year: 2016

We examined ringing recovery data of the Lesser Kestrel Falco naumanni in order to analyse its migration patterns and philopatry rates in Eastern Europe. In addition, we extracted counts of migrating birds from online databases and studied the use of the flyway as well as the phenology of both spring and autumn migrations through Greece. Birds appeared to migrate in the same mean direction in spring and autumn through the Italian and Balkan Peninsulas. During spring, movements took place on a broad front from March until mid- May with a peak in mid-April; in autumn, birds migrated through Greece on a narrower front from early August to early October, with most of individuals passing through Greece in mid-September. Finally, philopatry rates were higher for adults, while juvenile birds dispersed more often and at longer distances, up to 974 km away. Our results on migration patterns generally agree with those in other studies, but we found some evidence of long-distance premigratory movements towards mainland Greece that could also shape the narrower front migration in autumn. In addition, long distance dispersal movements of juveniles in southeastern Europe, where Lesser Kestrel populations show a fragmented distribution, could facilitate gene flow between populations, thus avoiding the negative effects of mating with genetically similar individuals.

Papageorgiou D.,University of Patras | Barboutis C.,Antikythira Bird Observatory | Kassara C.,University of Patras | Sinosgiokas,University of Patras
Current Zoology | Year: 2017

Every spring a huge number of passerines cross the Sahara Desert and the Mediterranean Sea on their way to their breeding grounds. Stopover sites after such extended barriers where birds can rest, refuel, and find shelter from adverse weather, are of crucial importance for the outcome of their migration. Stopover habitat selection used by migrating birds depends on landscape context, habitat patch characteristics, as well as on the particular energetic conditions and needs of individual birds, but it is still poorly investigated. We focused on a long-distance migrating passerine, the woodchat shrike, in order to investigate for the first time the species' habitat selection at a spring stopover site (island of Antikythira, Greece) after the crossing of the Sahara Desert and Mediterranean Sea. We implemented radio-tracking, color-ringing, and visual behavioral observations to collect data on microhabitat use. Generalized Linear Mixed Models were developed to identify the species' most preferred microhabitat during its stopover on this low human disturbed island. We found that high maquis vegetation surrounded by low vegetation was chosen as perches for hunting. Moreover, high maquis vegetation appeared to facilitate hunting attempts toward the ground, the most frequently observed foraging strategy. Finally, we discuss our findings in the context of conservation practices for the woodchat shrike and their stopover sites on Mediterranean islands. © The Author (2016).

Lucia G.,MEDRAPTORS | Agostini N.,University of Pavia | Panuccio M.,University of Pavia | Mellone U.,University of Alicante | And 3 more authors.
British Birds | Year: 2011

We document the first systematic survey of the spring and autumn migration of raptors along the central-eastern Mediterranean flyway, from observations on Antikythira, in southern Greece. More raptors were observed in autumn than in spring, mainly due to the much greater autumn passage of adult Honey-buzzards Pernis apivorus. Results suggest that the entire Greek population of Black Kites Milvus migrans uses this flyway. Our observations of Short-toed Eagles Circaetus gallicus suggest that adults breeding in southern and central Greece avoid Antikythira and follow a circuitous migration via the Bosporus or Dardanelles, while some juveniles in autumn appear to attempt a sea crossing via Crete to Libya. © British Birds 104. May 2011.

Agostini N.,University of Pavia | Lucia G.,University of Alicante | Mellone U.,University of Alicante | Panuccio M.,University of Pavia | And 3 more authors.
Italian Journal of Zoology | Year: 2012

This study provides the first systematic survey of spring and autumn migration of adult European Honey Buzzards (Pernis apivorus) along the Central-Eastern Mediterranean flyway. Observations were done in 2007 and 2008 over the island of Antikythira (southern Greece), located 33 km NW of Crete. A total of 135 birds were counted during spring, 101 in 2007 and 34 in 2008. During post-reproductive movements, the passage of 2479 individuals was reported, 1131 in 2007 and 1348 in 2008. During both years an evident peak during the last ten-days of August occurred. These results clearly show differential spring and autumn migration of adult European Honey Buzzards through this region. Historical data concerning prevailing winds were used to reconstruct general wind patterns in the Central-Eastern Mediterranean region. It showed north-northwesterly winds between southern Greece and Libya during both spring and autumn, but very weak (&10 km/h) during the first period. We discuss two hypotheses to explain why the spring visible migration was so scarce: 1) a narrow migratory loop, with the European Honey Buzzards using a direct path between Libya and Peloponnesus during spring, bypassing Antikythira, and 2) a loop migration on a greater scale, involving a detour via the Bosphorus/Dardanelles' Strait and/or the Central Mediterranean, that would allow the European Honey Buzzards to minimise the water crossing but increasing the overall migration distance. In the light of previous studies on this species, the first hypothesis seems to be much more reliable than the second one. © 2012 Copyright 2012 Unione Zoologica Italiana.

Barboutis C.,University of Crete | Barboutis C.,Antikythira Bird Observatory | Henshaw I.,University of Stockholm | Henshaw I.,Uppsala University | And 2 more authors.
Ibis | Year: 2011

The Sahara desert acts as an ecological barrier for billions of passerine birds on their way to and from their African wintering areas. The Garden Warbler Sylvia borin is one of the most common migrants involved. We used body mass of this species from Greece in autumn and spring to simulate the desert crossing and to assess how body mass relates to fuel requirement. The flight range estimates were adjusted to the seasonal extent of the desert, 2200km in autumn and about 2800km in spring. In autumn, with an average fuel load of about 100% of body mass without fuel, birds were not able to cross the desert in still air, but northerly winds prevail during September and with the average wind assistance only one in 14 was predicted to fail to make the crossing. Body mass data from spring, after the desert crossing, was used to estimate departure body mass from south of the desert. The average wind assistance in spring is close to zero and departure body mass of the average bird arriving at Antikythira, a small Greek island, under such conditions was estimated to be 34.6g, which corresponded to a fuel load of 116%. Calculations based on 1% body mass loss per hour of flight showed slightly larger body mass loss than that calculated from flight range estimates. The results suggest that passerine birds about to cross the eastern part of the Sahara desert need to attain a larger fuel load in spring than in autumn. © 2011 The Authors. Ibis © 2011 British Ornithologists' Union.

Barboutis C.,University of Crete | Barboutis C.,Antikythira Bird Observatory | Mylonas M.,University of Crete | Fransson T.,Swedish Museum of Natural History
Journal of Biological Research | Year: 2011

During long-distance flights, birds catabolize not only fat but also protein, which results in structural or functional loss as protein is stored in organs. In this study we investigated breast muscle size in relation to body mass in garden warblers Sylvia borin before and after crossing the Sahara desert and the Mediterranean Sea in autumn and spring migration, respectively. Breast muscle size was measured by moulding the shape of the muscles of live birds. Samples were collected on the Greek island of Antikythira during spring after the barrier crossing and on Crete during autumn, where garden warblers prepare for barrier crossing on their southward migration. Breast muscle size on Antikythira was significantly smaller than the equivalent size measured on Crete. Breast muscle size followed the changes in total body mass when garden warblers had a low body mass while this relationship disappeared when body mass is above 17.5 g. The combination of low body masses and small breast muscle size of birds that have just crossed the Sahara desert and the Mediterranean Sea and landed on Antikythira indicates a severe protein break down. During extended flights, when fat reserves are insufficient, the use of protein can also be a lifeline to reach the destination. The weak association between body mass and breast muscle size during autumn implies that the increase of breast muscle, as a preparation for the barrier crossing, does not take place en route from breeding sites to the Mediterranean area.

Dimaki M.,Antikythira Bird Observatory | Dimaki M.,Hellenic Bird Ringing Center | Alivizatos H.,Hellenic Bird Ringing Center
Ringing and Migration | Year: 2011

The aim of this study was to describe the phenology of migration, biometrics and fat storage of the Red-breasted Flycatcher Ficedula parva in Greece, based on mist-netting studies on Antikythira Island. The data suggest that autumn passage takes place between early September and late October. Most birds that arrived on the island were carrying moderate fat reserves and only paused on Antikythira between nocturnal flights. © 2011 British Trust for Ornithology.

Christos B.,Antikythira Bird Observatory | Christos B.,University of Crete
Avocetta | Year: 2013

Greece is located at the southernmost end of the Balkan Peninsula and the shortest distance between Greece and north Africa is roughly 280 km. As raptors mostly fly over land exploiting thermal currents, the ecological barrier shaped by the Mediterranean Sea south of Greece, has a strong impact on the migration strategy adopted by each species. Using data from recent studies at three watchsites in Greece (island of Antikythira, Mount Olympus, National Park of Dadia-Lefkimi-Soufli) we discuss the migratory behaviour of some selected species. The three commonest species were the Eurasian marsh harrier Circus aeruginosus, the western honey buzzard Pernis apivorus and the short-toed snake eagle Circaetus gallicus. The first migrates on a broad front over the sea. A similar migration strategy is adopted also by the Eleonora's falcon Falco eleonorae. The western honey buzzard performs a loop migration strategy concentrating over the island of Antikythira in autumn but bypassing it in spring. The short-toed snake eagle, on the other hand, avoids the crossing of the Mediterranean Sea performing a long detour and crosses the sea at the Bosphorus. Observations suggest that the levant sparrowhawk Accipiter brevipes and the lesser spotted eagle Aquila pomarina adopt a similar strategy. Finally, species such as the common buzzard Buteo buteo and the sparrowhawk Accipiter nisus do not cross the Mediterranean Sea but move across Greece to winter in southern Greece. © 2013 CISO - Centro Italiano Studi Ornitologici.

Barboutis C.,Antikythira Bird Observatory | Chiatante G.,University of Pavia | Evangelidis A.,Antikythira Bird Observatory
Ornis Fennica | Year: 2016

A vast number of raptors migrates between the Western Palearctic and Africa every autumn. Species and/or populations of migratory raptors that choose to cross the Mediterranean Sea need to overcome an extended ecological barrier, which is particularly extensive in the area of east-central and east Mediterranean. We tested the selectivity of two raptor species to weather and phenology analyzing the data collected on a small Greek island throughout four different years. Weather selectivity of the two species shows both similarities and differences. The intensity of migration of both studied species is positively correlated with air temperature. The European Honey Buzzard selects days with strong tailwind assistance that helps to reduce flight time over sea thus decreasing mortality risk and energy consumption during this sea crossing. On the other hand, the Western Marsh Harrier seems to be less wind selective reaching the island in good numbers also with headwinds, probably because of its higher ability in using powered-flapping flight.

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