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JUNE 2010 WESTERN MARSH HARRIER MIGRATION 137
in southern continental Italy, 2002–2006 (E. Repaci years. In the Western Marsh Harrier, the occurrence
and N. Morabito unpubl. data, Cutini et al. 2006). of polygyny suggests an imbalance toward females
(Kjelle´n 1992, Clarke 1995, Agostini 2001), and in
Migration Route. Simultaneous direct observa- several populations of this species females outnum-
tions in 2000, 2002, 2003, and 2004 (Agostini et ber males (Simmons 2000). Thus, it is not unexpect-
al. 2001, 2003, 2004, Panuccio et al. 2005a), single- ed that migration counts involving the passage of
watchsite observations over various Mediterranean those populations reflect this imbalance. However,
islands (Rebassa 1995, Jonze´n and Pettersson considerable numbers of adult females and greater
1999, Paesani and Politi 2002, Vanni and Paesani numbers of juveniles do not cross the Mediterra-
2007, Roth and Corso 2007, Corso et al. in press, nean Sea during autumn migration, but winter in-
N. Agostini and D. Logozzo unpubl. data) and si- stead in western and southern Europe, including
multaneous radar and direct observation in south- Spain (Chiavetta 1981, Gonza`lez 1991, Clarke
ern Spain (Meyer et al. 2000, 2003; see Fig. 1) con- 1995, Handrinos and Akriotis 1997, Agostini and
firmed that this species crosses the sea on a broad Logozzo 2000, Panuccio et al. 2005b, Corso and
front, undertaking long water crossings heading Penna in press).
SSW-SW, as also suggested by band recovery data
(Sultana and Gauci 1982, Brichetti and Fracasso Migration counts and wintering surveys agree, at
2003, Reihmanis 2005, Spina and Volponi 2008). least in part, with findings of a satellite telemetry
In particular, most band recoveries in Italy and study. In particular, Strandberg et al. (2008) report-
Malta are of birds banded in central-eastern Eu- ed no distinct differences in timing (departure and
rope, the Baltic, and Scandinavia. Germany and arrival dates) of autumn migration among sex and
Czeck Republic are the most important countries age classes of birds of the population breeding in
of origin, followed by Finland, Sweden, Latvia, and southern Sweden. These individuals crossed the
Poland (Sultana and Gauci 1982, Reihmanis 2005, Mediterranean in September (median 25 Septem-
Spina and Volponi 2008). This direction of migra- ber) on a broad front, between Spain and north
tion (SSW-SW) might explain the scarce passage of Africa, mostly between southern Spain and Moroc-
this species at the Bosphorus along the SE flyway co. Two Western Marsh Harriers crossed the sea
(Zalles and Bildstein 2000). Systematic surveys of between northeastern Spain and Algeria, apparently
Western Marsh Harrier migration through Greece via the Balearic Islands. Only an adult male sum-
are still lacking, although the species is observed mering in Ukraine crossed the central Mediterra-
throughout the country, and banding recovery data nean region (Fig. 1). Three birds, one adult female
indicate that birds recovered in Greece were band- and two juveniles, did not cross the Mediterranean
ed in Finland, Lithuania, Poland, and Slovakia Sea, whereas a third juvenile did cross the Mediter-
(Handrinos and Akriotis 1997). Apparently, West- ranean but did not cross the Sahara Desert. As sug-
ern Marsh Harriers are little affected by the drift gested by surveys made in the central Mediterra-
of lateral winds in choosing parallel flyways over nean region during the winter (Agostini and
land and over water (Panuccio et al. 2005a). Logozzo 2000, Panuccio et al. 2005b), juveniles tend
to migrate shorter distances than adults and adult
Migration of Different Sex and Age Classes. The males to migrate longer distances than adult fe-
migration periods of adults and juveniles largely males, although this difference was not significant
overlap. Among adults, males tend to migrate earli- in the satellite telemetry study. Finally, four birds
er in the season, outnumbering females, with the tracked for at least two years showed considerable
exception of 2003 when, during observations made variation in the timing of migration among years,
over the islands of Marettimo and Pantelleria (be- perhaps as a result of breeding success or failure
tween western Sicily and Tunisia; Fig. 1), adult fe- (Strandberg et al. 2008).
males outnumbered adult males in the first ten days
of September (Agostini et al. 2004). In late spring A remarkable difference in numbers of adult males
and summer 2003 the weather was abnormally warm and adult females, with adult females outnumbering
in Europe and the heat was exacerbated by drought adult males, has been observed among birds wintering
(Wagner 2003), which may have negatively affected in south-central Italy, as in the Netherlands, Britain,
prey availability (Redpath et al. 2002) and influ- Spain, and Greece (Zijlstra 1987, Gonza`lez 1991,
enced adult females from migratory populations Clarke et al. 1993, Handrinos and Akriotis 1997, Agos-
to leave Europe earlier (Agostini et al. 2004) and tini and Logozzo 2000, Underhill-Day 2002, Panuccio
perhaps to migrate greater distances than in other et al. 2005b, Corso and Penna in press). Female West-
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