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The European honey buzzard Pernis apivorus is a summer visitor in Europe, wintering mostly in West-central Africa. Previous studies concerning timing of autumn migration in relation to sex groups provided contrasting results. In particular, a field survey made in southern Sweden did not report differences in timing, while a satellite study via GPS tracking on six adults, three males, and three females, revealed that the latter departed earlier. The aim of this 4-year study is to further investigate the timing of autumn migration in this species carrying out observations at the Strait of Messina, a bottleneck located along the Central Mediterranean flyway, between August 10th and September 30th 2016–2019. Adult European honey buzzards concentrated the passage between late August early September, with females passing on average 5 days earlier than males. It is suggested that a different role of sexes concerning exhibition of territorial displays during the late breeding season, would explain differences between sex groups in timing of both moult and autumn migration.

The Western marsh harrier Circus aeruginosus is a partial migrant with populations breeding in eastern and northern Europe migrating south and wintering mostly in sub-Saharan Africa. During autumn ...

Summary Movement ecology and environmental factors are topics of paramount importance to consider when planning conservation programmes for target species. Here we discuss this topic by reviewing the available information related to the Egyptian Vulture Neophron percnopterus, with reference to the remnant breeding population of Southern Italy, of high conservation concern and subject of a long-term captive-breeding re-stocking programme. We describe how adverse wind conditions over the Central Mediterranean Sea make the sea-crossing challenging with detrimental effects on the survival of inexperienced birds, and coupled this information with count data of migrating Egyptian Vultures. Furthermore, we indicate how low population size and scarce opportunities in meeting migrating conspecifics could potentially lead juvenile Egyptian Vultures to follow unfavourable migratory routes, with possible repercussions on survival. We postulate how these concomitant factors could be indirectly influencing the long-term survival of this small population, principally affected by anthropogenic threats. We also discuss how the same factors could actually be affecting captive-bred young individuals released in late summer in southern continental Italy, in the framework of the restocking programme. An integrative approach with tailor-made release methods, which also takes into account the age of released birds and geographical and environmental factors, would likely be useful for a more goal-oriented and long-lasting conservation outcome, for the preservation of this endangered scavenger.

A growing number of ecological studies suggest that animal distributions are not only influenced by classical ecological features such as habitat availability, but also by the motion capacity of the studied animal. Here we analyse the diversity and density of two wintering raptor communities from Crete and Sicily, two large Mediterranean islands located along migratory flyways. We performed 611 and 1030 km of transects in Crete and Sicily respectively, examining the spatial distribution of raptors in relation to land use, topography, raptor species diversity and abundance. Our results show that community diversity and specific abundance are strictly related in accordance with the ‘More Individuals Hypothesis’. Comparing the two most common raptors, the density of the Eurasian kestrel was the highest in Sicily and that of the common buzzard in Crete. An overall positive effect of Eurasian kestrel density on that of the common buzzard was found in both islands, but higher in Crete. Our findings suggest that the distribution and density of the Eurasian kestrel, because of its higher movement ability, are less influenced by the presence of ecological barriers along potentially migratory flyways. We cannot exclude that higher inter specific competition with common buzzards in Crete might have pushed the smaller species to cross the Mediterranean Sea in order to overwinter in Africa.

The short-toed snake eagle (Circaetus gallicus) is distributed in the Palearctic and Indomalayan region. Palearctic populations are migratory, overwintering mainly in the Sahel region south of Sahara. Because of its size and morphology, this species mostly uses soaring-gliding flight over land during migration avoiding long sea-crossings. As a result, large concentrations of migrants are observed at straits and along coastal and isthmus areas, with the highest counts reported at the Strait of Gibraltar during both spring and autumn. Migrating individuals belonging to populations of the Iberian Peninsula. France and Italy converge at this site. There is no evidence of a migratory flow across the Sicily Channel. Those breeding in Eastern Europe concentrate at the Bosphorus. part of those of Central-Western Asia at Batumi (Georgia). In the Middle East and North Africa, thousands are observed around the Gulf of Iskenderun, in Israel, in the area of Suez and along the western coast of the homonymous Gulf. Populations breeding in Italy and Greece use extremely detoured routes concentrating at the Strait of Gibraltar and at the Bosphorus. respectively, during both spring and autumn. Large numbers of juveniles learn these migration pathways following elders encountered en route. Recent studies made by satellite telemetry and involving mostly juveniles and immatures well described migration pathways of this species.

Durante la migracion de primavera, algunas decenas de miles de abejeros europeos que invernan en el Africa subsahariana cruzan el Mediterraneo central para llegar a sus zonas de reproduccion en Europa central y oriental. Al hacerlo, concentran el paso a traves del canal de Sicilia, pero eligen diferentes rutas migratorias en respuesta a las diferentes condiciones del viento. Este estudio investigo la influencia de las condiciones del viento local y regional en los patrones de movimiento de esta especie a lo largo del estrecho de Mesina, un cuello de botella migratorio ubicado entre el este de Sicilia y el sur de Italia continental, donde algunas aves rapaces son victimas de la caza furtiva cada primavera. Se realizaron observaciones simultaneas en cuatro puntos de observacion, tres en el lado siciliano y uno en el limite continental (lado calabres). Los vientos del noroeste prevalecieron en el Estrecho durante los dias con pico de migracion. No obstante, los patrones locales levemente diferentes de vientos horizontales y verticales en cada sitio de observacion afectaron la formacion de bandadas y dieron forma al paso de las aves rapaces a traves de este cuello de botella, ampliando el frente de migracion. Los resultados confirman que la magnitud de la migracion primaveral del abejero europeo en el Estrecho se ve fuertemente afectada por los patrones de viento en el canal de Sicilia. En particular, los migrantes se concentran en este cuello de botella despues de cruzar el Canal con vientos del noroeste el dia anterior. En conclusion, al interpretar el comportamiento migratorio tanto a escala local como regional, este trabajo puede ayudar a planificar un seguimiento mas eficiente de los abejeros europeos a traves del Estrecho y mejorar la ubicacion de las acciones de conservacion.

Summary. Afro-Palearctic migrants move between breeding and wintering grounds along flyways determined by several factors (bird morphology, geography, behavioural adaptations) and raptors often concentrate at straits to avoid long sea crossings. Here we test the hypothesis that raptor passages across different areas of the Turkish straits are similar in species composition as well as flight behaviour. We made simultaneous observations at the Bosphorus and at the Dardanelles in autumn 2010. We tested the influence of weather, time of day and flock size on the intensity and spatial shift of migratory flow as well as the tendency to cross the Dardanelles Strait rather than follow the peninsula. We also collected information of the flight altitude of raptors using an optical range finder. The species composition observed at the two sites was completely different, with eagles predominating at the Bosphorus and small and medium-sized raptors predominating at the Dardanelles Strait. Compensation for wind drift a...

Capsule: Juvenile Short-toed Snake Eagles Circaetus gallicus hatching in the peripheral populations of Greece and Italy have limited opportunities for social learning of migration routes compared to those hatched elsewhere.Aims: To test the prediction that there would be a higher degree of migration synchrony between adult and juvenile Short-toed Snake Eagles originating from peripheral populations and using an extremely detoured flyway, when compared to other populations using a direct overland flyway.Methods: We use linear regression models to compare seasonal changes in the age distribution of migrating Short-toed Snake Eagles counted at two migration watch-sites in Italy (Arenzano) and Georgia (Batumi), along a detoured and a direct flyway, respectively.Results: Juveniles migrated a few days later than adults at both sites and the age ratios recorded at these two sites was similar. The daily proportion of juveniles increased along a similar slope during the migration season, thus showing a similar degree of synchrony between the age classes on both flyways.Conclusions: Contrary to our hypothesis, juvenile and adult migration is not more synchronized in peripheral populations using a detoured flyway compared to a core population using a direct migration flyway. Our results suggest that juveniles do not learn detours to complete trans-Mediterranean migration from their parents, but from other elders.

We investigated the directions of migration (reversed vs. expected) of raptors approaching a geographical strait in relation to local wind conditions, time of day, flock size and location of the observation post (coastal zone vs. inland zone). Fieldwork was conducted during autumn migration in 2011, 2012 and 2013 at a migratory bottleneck located in the southernmost part of the Italian Peninsula (Calabrian Apennines), using four watch points. In this area, migrating birds face the narrowest water surface between continental Italy and Sicily, the Strait of Messina. The only species showing substantial reverse migration was the short-toed snake eagle (Circaetus gallicus). In particular, eagles, mostly first calendar year (cy) birds, showed this behavior when passing closer to the coast (5 km inland of the Strait of Messina). Our results could reflect the reluctance of these birds to head south when approaching this relatively short stretch of sea, even before reaching the coastline. This behavior co...

Water surfaces are natural barriers for raptors mostly using soaring–gliding flight over land during migration. Among these, the European Honey Buzzard ( Pernis apivorus) is a total migrant, breeding in Europe and wintering in central western Africa. Each spring thousands of buzzards undertake long sea crossings between Tunisia and southern Italy, concentrating over small islands en route to central eastern Europe. The aim of this research is to investigate the influence of wind patterns on the flyways used by these raptors during this critical phase of migration through field observations at four small Mediterranean islands (Pantelleria, Marettimo, Ustica and Panarea) and at the Straits of Messina between 20 April and 20 May 2006–2013. In our analyses, peak days were considered for each site. This eight year multisite study allowed the collection of a large data set. While crossing the Channel of Sicily, migrants concentrated over Pantelleria (southern side of the Channel) during moderate NW winds, and over Marettimo (northern side) during weaker southerly winds. Over the island of Ustica (north-western Sicily, Tyrrhenian Sea) raptors were observed mostly with weak southerly winds. Over the island of Panarea (northeastern Sicily) and at the Straits of Messina, European Honey Buzzards passed with weak winds from W and NW, respectively. The average flock size during the peak days was significantly higher over the island of Pantelleria, where birds migrated during the stronger winds. The results of this study show that wind patterns affect both migration pathways and flocking behaviour of this species while crossing large water surfaces.

Capsule: Raptor migration attracts the interest for different reasons, but not all raptor counts achieve the goal of repeatability through the use of standardized field protocols, and this does not allow comparisons of data to be made across years and sites. Aims: We analysed migrating raptor count activities in Italy to verify the interest on this phenomenon by identifying organizers of such counts, and we ascertained the use of a minimum repeatable field protocol (MRFP), and the implications of using it or not. Moreover, we tested the use of radar to support field monitoring. Methods: We analysed 298 migrating raptor counts carried out between 1984 and 2016 by considering characteristics of raptor counts at migratory bottlenecks (number of years covered, use of MRFP, numbers of raptors counted, etc.). In addition, we analysed two case studies using radar to evaluate the effectiveness of raptor counts. Results: There is a growing interest in raptor migration, as well as an increasing use of a MRFP, although differences between counts emerged, probably due to the different aims of the promoting organizations. At sites not using MRFP, more raptors were counted than at other sites, probably because of a greater bias in the data collected. Radar is able to clarify the water-crossing behaviour of raptors at coastal sites, and allows the proportion of birds passing undetected by observers to be evaluated. It also provides data on the spatial density of migrants across a sample area. Conclusions: The use of MRFP is important to harmonize data collection and is necessary to allow comparisons across years and sites. Moreover, the use of radar can be recommended for optimizing raptor monitoring schemes.

We investigated the visible migration of raptors when approaching a water surface in relation to local wind conditions, time of the day and topography. Observations were made during autumn migration in 2011 and 2012 at a watchsite located in the southernmost part of the Calabrian Apennines (southern continental Italy). In this area, the Apennines show differential topographical features with a plateau west of the mountain ridge. West–southwest of the plateau lies the Straits of Messina, the narrowest water surface between southern continental Italy and eastern Sicily. The passage of migrants was recorded along the ridge of the mountain chain and over the plateau. As expected for a soaring raptor, European Honey Buzzards were detected mostly during midday and early afternoon, while significant numbers were seen toward sunset probably when flying at lower altitude to roost. In addition, they were detected during strong winds when exploiting deflection updrafts, avoiding wind drift and limiting the n...

Background The Western Marsh Harrier (Circus aeruginosus) is a partial migrant with the populations from Eastern and Northern Europe migrating south to sub-Saharan Africa. During the autumn migration, that is peaking in September, harriers move on a broad front heading SW and undertake long sea-crossings en route to their wintering quarters, passing in substantial numbers through Italy and Malta with the highest concentrations recorded at the Strait of Messina. Most of the individuals migrating across the Strait are heading for the wintering quarters in Africa, while fewer spend the winter in Sicily. Methods In a 5-year study (2011‒2015), between 26 August and 30 September, we determined age and sex of autumn migrating harriers through this flyway. In 2014 we determined, by marine radar and optical range finder, the flight altitude of migrating harriers. Results A total of 10,261 Western Marsh Harriers were counted during the whole study, with an average of 2052 per autumn season. Adults outnumbered juveniles and males outnumbered females. Harriers flew at lower altitudes during the morning while large flocks flew lower than single birds or small flocks. Conclusions Our observations are consistent with previous surveys and confirm that adult males have a tendency to migrate over a long distance, while substantial numbers of adult females and juveniles do not head for the wintering quarters in Africa. Finally, flight patterns recorded can be explained by a more pronounced flapping flight of Western Marsh Harriers during migration.

Migrating birds adjust their behaviour in order to reach their final destination safely and in a timely manner. In doing so, they fly at different altitudes, but unlike passerines, raptors do not explore all air levels searching for the best tailwind assistance. Soaring species migrate over the mainland using updrafts to optimize soaring-gliding flight and reaching higher altitudes during midday. However, there is little information on which variables affect their flight altitude when facing the open sea, where thermals are very weak and they are forced to use powered flapping flight for a long time. To fill this gap, we recorded the flight altitude of migrating European Honey Buzzards Pernis apivorus as they crossed the Tyrrhenian Sea (Central Mediterranean) and passed over a small island. During four migratory seasons, we recorded the altitudes of birds when they reached the NE coast of Ustica, a volcanic island between Sicily and central Italy, and analysed data in relation to several variables. The results showed that the tendency to continue migrating, flock size, and wind speed are the most important features in explaining height variation in migrating European Honey Buzzards facing the open sea.

The nominal subspecies of the Black Kite is a summer resident in Europe and Asia that winters mostly in western Africa, although numbers of birds wintering in the Mediterranean area are increasing. During migrations, tens of thousands are observed migrating through the Strait of Gibraltar between Spain and Morocco, along the eastern side of the Black Sea, and in the Middle East, while substantial numbers cross the central Mediterranean and the Bosphorus. This paper provides a review of research concerning migration and its relationship with foraging behaviour in a circannual perspective. In particular, research made both by satellite tracking and by visual observations suggests a more evident time-selected migration during autumn rather than spring. Moreover, differences in timing occurring among different flyways could be explained either by different rates of intra-specific competition in areas with different breeding density and/or by different distances between wintering and breeding grounds.

Migratory behavior of raptors is affected by several factors, including weather, geography, and topographical features. Here we provide information on how these factors may affect the behavior and detectability of the Short-toed Snake-Eagle (Circaetus gallicus). We observed passage of Short-toed Snake-Eagles at two watchsites along mountain chains in northeastern Greece (Mount Olympus) and northwestern Italy (Arenzano) during the peak periods of migration in autumn 2009 and spring 2010. More Short-toed Snake-Eagles were observed in spring than in autumn; this difference was more evident at Arenzano. Temperatures influenced the number of migrants observed. In particular, the number of individuals observed decreased drastically when temperatures were higher than 24°C during post-reproductive movements. At both sites, daily patterns showed a lower proportion of raptors observed during midday and early afternoon in autumn than in spring. These results suggest that, during autumn, individuals may pass...

The Western Marsh Harrier (Circus aeruginosus) is a summer visitor in northern, eastern, and central Europe. Some birds, mostly juveniles and adult females, winter in the Mediterranean region, while others cross the Sahara to winter in tropical Africa. Unlike other Accipitridae, which use primarily soaring flight over land during migration, Western Marsh Harriers tend to move on a broad front, with long, powered flights over water. In the last two decades, several researchers have investigated the migration of this species through the Mediterranean basin using direct observations, radar, band recovery data, and satellite telemetry. We here present a short review of these investigations and results.

We investigated the water-crossing behavior of Western Marsh Harriers (Circus aeruginosus), mostly adults, and European Honey Buzzards (Pernis apivorus), mostly juveniles, in relation to wind conditions, time of the day, flocking and age classes, at a watchsite in central Italy during the autumn migration en route to Africa. Although European Honey Buzzards are less suited than Western Marsh Harriers to undertake long sea crossings, they were more inclined to leave the coast when migrating in flocks. Few birds of both species chose to fly along the coast. Western Marsh Harriers, such as European Honey Buzzards migrating alone, undertook the water crossing rather than stopping migration (birds roosting at the site or flying back inland) during the absence of wind and vice versa during head winds. Conversely, European Honey Buzzards migrating in flocks were not affected in their decision (crossing or stopping migration) by wind direction. Both species undertook the water crossing rather than stopping migration during mornings and vice versa during afternoons. Finally, in both species, adults and juveniles showed the same behavior in front of a water barrier. This result was expected in the case of the Western Marsh Harrier but not from the European Honey Buzzard since, in this species, the water-crossing tendency is age dependent with adults avoiding sea crossings. Our study confirms that flocking significantly affects the water-crossing behavior of European Honey Buzzards during migration. Moreover, in this species, inexperience of juveniles and presumably younger adults, about the high energetic costs of long powered flight and about the existence of shorter routes over water, might explain the strong water-crossing tendency shown by migrants independently from their age.

Timing, age classes and water-crossing behaviour of Black Kites (Milvus migrans) during spring migration across the Central Mediterranean The main migratory passage of Black Kites across the Mediterranean Sea occurs at the Strait of Gibraltar, where the migration peak is observed in early March. Conversely, in the Central Mediterranean the migration of this species is scarce during the supposed peak period, while hundreds of individuals are observed migrating later in the season, mostly in April and May. In the present study we investigate the spring migration of Black Kites at two sites of the Central Mediterranean, the island of Ustica and the Strait of Messina. Timing, age classes and water-crossing behaviour of this species suggest that large numbers of non-breeders use this route during spring. However, a peculiar migration timing of breeding pairs belonging to the Italian population cannot be excluded.

Factores Que Determinan Las Rutas De Pernis apivorus Durante La Migracion De Primavera En La Depresion Central Del Mediterraneo Observamos a individuos de la especie Pernis apivorus en puntos migratorios cerca del Mar Mediterraneo central. Se realizaron observaciones simultaneas entre el 25 de abril y el 20 de mayo de 2004 en las islas Marettimo, Pantelleria (localizadas a los costados norte y sur del canal de Sicilia, respectivamente), Panarea y en los estrechos de Messina (ambos al el este de Sicilia). La bandada se utilizo como unidad de muestreo. Un total de 216 bandadas pasaron via Pantelleria, la mayor parte durante vientos N-NNE y W-WNW-NW con un pico evidente a finales de la tarde y durante el atardecer. Las aves escogieron cruzar por la ruta mas corta entre el norte de Africa y Pantelleria utilizando una migracion curvilinea sobre el agua. Durante los periodos de viento con direccion sur-oeste, P. apivorus se registro principalmente en Marettimo a lo largo de la ruta mas directa hacia el oeste de...

During autumn migration across the Central Mediterranean, adult Honey Buzzards cross the sea at its nar- rowest point, between western Sicily (southern Italy) and the Cap Bon Peninsula (Tunisia). This study investigated the influence of prevailing winds and geography on the orientation behaviour of migrants during this sea crossing by observations over two islands, one on the northern side, the other on the southern side of the Channel of Sicily. The flock was taken as the sampling unit. Honey Buzzards reached the island of Marettimo, approx. 30 km off western Sicily and 130 km NE of the Cap Bon Peninsula, regardless of the direction of the prevailing winds (NW and S). By con- trast, Honey Buzzards passed via Pantelleria, about 110 km SW of western Sicily and 70 km ESE of the Cap Bon penin- sula, mostly during NW winds. Birds reached Pantelleria from the NE and left the island flying WNW. They applied true navigational abilities in choosing the shorter crossing between Pantelleria and Tunisia and showing a curvilinear migration. Our results agree in part with the "optimal use of wind" hypothesis. In particular, wind, geography and navigational abilities seem to interact to shape the orientation behaviour of migrating Honey Buzzards, perhaps to minimize the risks of non-stop powered flight over the water.

Analysis of the Spatial Migration Patterns of Adult Honey Buzzards (Pernis apivorus) During Spring and Autumn in the Central Mediterranean In this paper we analyse the spatial migration patterns and the water crossing tendency of adult Honey Buzzards during spring and autumn migration in the Central Mediterranean region. In this area, during spring, these long-distance migrants wintering in western-central Equatorial Africa, concentrate crossing the sea between Africa and Europe through the Channel of Sicily, about 150 km wide, at least part of them via the islands of Pantelleria and Marettimo. When they reach western Sicily most of them fly east, along the mountain chain of northern Sicily, towards the Strait of Messina. Nevertheless, thousands of birds use a more direct route to reach the continental mainland undertaking the crossing of the Tyrrhenian Sea via Ustica and the Lipari Islands. During autumn the migration of adult Honey Buzzards is less consistent. They tend to follow the Italian Peninsula and northern Sicily reaching Africa through the Channel of Sicily while very few cross the Tyrrhenian Sea. On the contrary, during their first migration, large numbers of juveniles, moving about two weeks later than adults, cross the Central Mediterranean region on a broader front presumably along NE-SW innate axis. It is supposed that larger numbers of adult Honey Buzzards choose the central Mediterranean route during spring migration to reach earlier their breeding areas in eastcentral Europe. During post-reproductive movements most of them would circumfly the Mediterranean Sea crossing at the Strait of Gibraltar and at the Bosporus. In this picture the discovery of more direct routes between breeding and wintering areas made by juvenile birds during their first migration may have the adaptive value.

Crossing the sea en route to Africa: autumn migration of some Accipitriformes over two Central Mediterranean islands Observations were made on the autumn migration of Accipitriformes over the islands of Marettimo and Pantelleria, located between western Sicily and Tunisia (Central Mediterranean). A total of 7451 raptors was counted between 24 August and 12 September 2003, mostly adult Honey Buzzards Pernis apivorus - 4045, and Black Kites Milvus migrans - 2489. Mixed-age flocks were regularly reported for the Black Kite (1956 adults and 533 juveniles estimated) confirming information transmission concerning orientation behaviour in this species. Although in the Honey Buzzard juveniles tend to migrate later than adults, crossing the Mediterranean on a broad front mostly after mid-September, we observed some mixed-age flocks, estimating the passage of 3830 adults and 215 juveniles. In particular, over Pantelleria we recorded in seven cases juveniles in flocks of adults heading towards WNW, presumably learning (similarly to juvenile Black Kites) the shortest route over water to reach Africa from this site. A total of 72 Egyptian Vultures Neophron percnopterus - 62 adults, 6 juveniles and 4 sub-adults - was counted over Marettimo confirming that their greatest concentration during autumn migration through Italy occurs at this island. In this species, all juveniles were seen migrating in flocks of adults. Finally, the passage of hundreds of Marsh Harriers Circus aeruginosus was reported, mostly over Pantelleria. Among adult harriers, it was possible to estimate the passage of birds belonging to different sex classes; unlike in the previous studies made in central, southern continental Italy and Malta during autumn migration, adult females outnumbered adult males (372 vs 298 individuals). Finally, considering the huge number of Accipitriformes observed, Pantelleria, so as Marettimo, should be enclosed among Important Bird Areas for the autumn migration of raptors in the Mediterranean basin.

Autumn migration of Marsh Harriers (Circus aeruginosus) across the Central Mediterranean in 2002 Observations on the autumn migration of the Marsh Harrier were made at two sites of the central Mediterranean: the Circeo promontory (central Italy) and the island of Malta. The aim was to investigate the passage of birds belonging to different sex and age classes. At the Circeo promontory a total of 787 individuals was counted, 37.5% of which were juveniles. Over the island of Malta the passage of 1535 Marsh Harriers was recorded with an evident peak comprising 906 birds on 13 September. At both sites males outnumbered females, mostly within the first half of September. Because, at least among adults, an imbalance towards females has been reported in the population wintering in central Europe, our results suggest that adult males could have a stronger tendency to migrate over a long distance, crossing the central Mediterranean area in large numbers. Whereas females, being larger than males, are able to tolerate colder temperatures and fast longer. Finally, our counts confirm the increase of the European population of the Marsh Harrier, which has occurred for the last three decades.

Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs. However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping (powered) flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we conducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio (calculated as the wing span squared divided by wing area), the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces.

Presence and distribution of ecological barriers shapes the distribution of migratory birds as well as any other living organism. In Italy, short-toed snake eagles (Circaetus gallicus) breed in the northern and western areas of the peninsula but the species is rare in the south or the islands. The Italian population of this species migrates across the Mediterranean at the Strait of Gibraltar rather than crossing the large stretch of sea between Sicily and Tunisia. This suggests that, in Italy, fall migration is oriented south–north and spring migration north–south. In this paper we test the hypothesis that the accessibility of the suitable habitat area along the Italian Peninsula is in relation to the geographical migration pattern of the studied species. We integrated information from the movement ecology, the geography and the traditional ecological features in order to provide an ecological explanation of the current biogeographical pattern of our model species. We compared statistical models with and without latitude as a predictor. Each model was based on ecological and geographical variables, including land use, prey availability, spatial distribution of environmental elements (patch analysis), geomorphology, and geography. These models predict two patterns of suitability for short-toed snake eagles in Italy. Our results suggest that the abundance of this species increases with latitude despite the existence of large areas of suitable habitat in southern Italy. We suggest that the actual distribution of the short-toed snake eagle in Italy is influenced by the particular migration path used by this population, supporting the hypothesis that this species is still colonizing the Italian Peninsula through an unexpected colonization direction from north to south.

MIGRACION PRIMAVERAL DE PERNIS APIVORUS A LO LARGO DEL CORREDOR CERDENA-CORCEGA (MEDITERRANEO CENTRAL) El objetivo de este estudio fue determinar si existe un paso primaveral significativo de Pernis apivorus a lo largo del corredor Cerdena-Corcega (Mediterraneo Central) durante el pico del periodo de migracion. Observamos rapaces migratorias entre el 1 y el 14 de mayo del 2005 en Bocche di Bonifacio, en el punto mas angosto del estrecho entre estas islas. Comparamos conteos realizados en Bocche di Bonifacio con aquellos hechos en los Estrechos de Messina, entre el este de Sicilia y el sur de Italia continental, donde se presenta la mayor concentracion de rapaces del Mediterraneo central durante la migracion de primavera. Se registraron 103 individuos de P. apivorus en Bocche di Bonifacio, mayormente (40.8%) migrando solos. De estos, 89 aves cruzaron el mar en direccion hacia Corcega. En los Estrechos de Messina se contabilizaron mas de 14 000 individuos de P. apivorus, mayoritariamente (99.1%) migrando en...

Observations on the autumn migration of raptors were carried out on the Calabrian Appennines in the area where the Italian peninsula is only 30 km wide. We used three different watch points at the same time between 24 August and 12 September 2005 and 2006. We observed 4,842 raptors in 2005 and 5,324 in 2006; most of these were Honey Buzzards, Black Kites, Marsh Harriers and Montagu’s Harriers.

The western honey buzzard Pernis apivorus is a summerresident in Europe that winters in west-central Equator-ial Africa (Cramp and Simmons 1980). Individuals ofdifferent ages migrate in different periods. Adults moveabout two to three weeks earlier than juveniles (Kjelle´n1992, Agostini and Logozzo 1995). In a recent paper,Hake et al. (2003) reported data on the autumnmigration of nine honey buzzards (six adults and threejuveniles) from Sweden that were tracked by satellite.The results showed that whereas adults crossed theMediterranean Sea at the Straits of Gibraltar, juvenilesmigrated on a broader front and undertook longpowered flights ‘‘somewhere’’ over the open sea. Visualobservations in the central Mediterranean region clearlyshowed the existence of different spatial migrationpatterns between adult and juvenile honey buzzardsduring post-reproductive movements (Agostini andLogozzo 1997, Agostini et al. 1999, 2000, 2002).Unfortunately, Hake et al. did not quote these sourcescausing a gap in their work. Here I review these papers inan effort to fill this gap.In the central Mediterranean, adult honey buzzardsmigrate mainly from late August through early Septem-ber (Agostini and Logozzo 1995). Here they tend tofollow the Italian peninsula and, upon reaching theStraits of Messina between the ‘‘toe’’ of southern Italyand Sicily turn west. Many of them will fly across Sicily,and then southwest across the Sicilian Channel headingtowards the Cap Bon peninsula (Agostini and Logozzo1997, Agostini et al. 2000, Fig. 1). The experienced adultbirds probably use the reverse of the spring route(Agostini et al. 1994, Agostini and Logozzo 1998).Thus Agostini and colleagues concluded that adulthoney buzzards apply true navigational abilities, thusavoiding a longer flight across the central Mediterra-nean, probably to minimize risks and energetic costs(Agostini and Logozzo 1997, Agostini et al. 2000). Onlya few juveniles migrate together with adults on thismigration route (Agostini et al. 1999, 2000). Most ofthem arrive at least two weeks later at the coasts of theMediterranean, typically in all juvenile flocks or alone.Unlike adults, juveniles passing through southern con-tinental Italy after the second weekof September take offin southern Sicily and then concentrate over Malta toreach probably Libya, moving along a NE-SW innateaxis (Fig. 1, Agostini and Logozzo 1995, Agostini et al.1999). During their first migration, inexperienced juve-nile honey buzzards are not familiar with the shortestroute to cross the central Mediterranean and presumablyare moving along innate migratory directions. It isinteresting to note that observations at the Circeopromontory (central Italy, Fig. 1) and over Maltasuggest that at least part of the juveniles crossing theTyrrhenian Sea change their innate direction of migra-tion in response to the open water (Agostini et al. 2002,see also Agostini et al. 2004). In the case of juvenilehoney buzzards Agostini and colleagues (2000, 2002)concluded that these spatial migration patterns mayexplain why they show a broader front in migration, andwhy concentrations of juveniles but only a few adults arereported at many islands of the Mediterranean, such asCabrera, Corsica, Capri, Pianosa, Malta andCyprus (Frost 1994, Rebassa 1995, Agostini et al.

The predatory behaviour of captive wild kestrels was investiga ted to ascertain whether prolonged captivity, with no predation opportunities, could affect prey capture. Thirty kestrels were ob served. After a 48‐hour fast they were offered a live laboratory mouse. The behaviour before and after prey appearance, and la tency to predation were recorded. There was no difference in cap ture efficiency correlated with kestrel age, but adults performed preening significantly more often than young birds. Moreover, a clear inverse correlation was found between the latency of preening and of predation. Therefore, prolonged captivity associated with inactivity does not seem to exert a negative influence on predation in this species.