JUVENILE DISPERSAL OF LAMMERGEIERS
One of the most-visited posts in this blog is that
about the presence of Lammergeiers (Gypaetus barbatus) in
Extremaduran published
in August 2011. At that time we gathered information about direct
sightings (and there have been others since then) and from maps showing
the tracking of satellite-tagged individuals that was posted on-line
by the Gypaetus Foundation (sadly since July 2012, they have discontinued
this). The information presented was based simply of daily records,
without any analysis to speak of. Given that recently a study has
been published about the movements of pre-adult Lammergeiers in Europe
(Margalidaet al. 2013), we can show a couple of very relevant maps.
The analysis was based on satellite-tracked individuals from three populations: the
Alps (reintroduced population), the Pyrenees (native population) and
Cazorla-Segura (where reintroduction is starting). The three populations show different
behaviours. The Alpine population disperses across the whole
length of the mountain range with some sporadic movements as well south
(to the northern Apennines in Italy) and north (plains of Central Europe).
The Pyrenean Lammergeiers are much less mobile, restricted to the ranges
where they fledged. The Andalucian birds from Cazorla are the greatest travellers,
with displacements and stays in the mountainous massifs across the Iberian Peninsula,
especially in the southern half (the Béticos, Sierra Morena and the
Sistema Central), but also the Pyrenees (especially western part), the
mountains of northern Spain and the Picos de Europa. Although the dispersal
of these Lammergeiers varies greatly between individuals, there is a
general pattern of birds staying during their first months of life close
to their release areas, followed by a dispersal when about a year old
to the high mountain ranges in Iberia (so far none have been found outside
the Peninsula).
In the case of Extremadura, although
there are pre-2008 records of individuals of presumed Pyrenean origin,
not a single satellite-tracked individual from this population has arrived
in our region. On the other hand, there is a regular presence of
Cazorla birds in the Gredos Mountains (La Vera, Jerte and Ambroz
in Cáceres) and the north-east of Badajoz.
Other parts of Extremadura visited by Lammergeiers include Las Hurdes,
Villuercas and the river system of Tajo-Monfragüe, the central ranges
of Badajoz and the Sierra Morena in Badajoz.
Reference:
Margalida, A., Carrete, M., Hegglin, D., Serrano, D., Arenas, R. &
Donázar, J. A. 2013. Uneven large-scale movement patterns in wil and
reintroduced pre-adult bearded vultures: conservation implications.
PLoS ONE 8(6): e65857. doi:10.1371/journal.pone.0065857 [download]
Translated by Martin Kelsey.
