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Population size and breeding performance of the Lanner Falcon Falco biarmicus in
Sicily: conservation implications
M. Di Vittorio
a,b
, E. Di Trapani
b
, S. Cacopardi
b
, G. Rannisi
b
, A. Falci
b
, A. Ciaccio
b
, A. Sarto
b
, S. Merlino
b
,
M. Zafarana
b
, S. Grenci
b
, G. Salvo
c
, M. Lo Valvo
d
, A. Scuderi
b
, L. Murabito
b
, G. La Grua
b
, G. Cortone
a
, N. Patti
b
,
L. Luiselli
e
and P. López-López
f
a
Ecologia Applicata Italia, Roma, Italy;
b
Gruppo Tutela Rapaci Pedara (CT), Italy;
c
Racalmuto (AG), Italy;
d
Dipartimento di Scienze e Tecnologie
Biologiche, Chimiche e Farmaceutiche. Laboratorio di Zoologia applicata, University of Palermo, Palermo, Italy;
e
IDECC –Institute for
Development, Ecology, Conservation and Cooperation, Rome, Italy;
f
Cavanilles Institute of Biodiversity and Evolutionary Biology, University of
Valencia, Valencia, Spain
ABSTRACT
Capsule: We report a significant reduction in population size and breeding success for the Lanner
Falcon Falco biarmicus in Sicily, its biggest stronghold in Europe, since the latest coordinated survey.
Aims: To provide updated information on current population size of Lanner Falcon in Sicily and to
compare breeding parameters with those obtained in previous studies.
Methods: We performed an intensive coordinated field survey and literature review of breeding
success parameters across the species range.
Results: Overall, we monitored 126 territories throughout Sicily where the species had been
reported in the last 15 years. Lanner Falcons were present only in 60 of them. Mean nest
productivity (± standard deviation) was 1.09 ± 1.18 fledged young/checked pairs, flight rate was
2.22 ± 0.52 fledged young/successful pairs and breeding success was 49.0%.
Conclusions: Indirect measures aimed at preventing abandonment of occupied territories should
be applied, for instance by developing a network of priority areas and slowing down degradation of
the pseudo-steppe habitats by agri-environmental schemes. Additionally, direct measures aimed at
preventing nest robbery, including the organization of nest guarding activities, and reduction of
anthropogenic disturbance and illegal shooting, must be encouraged in order to avoid territory
abandonment.
ARTICLE HISTORY
Received 2 January 2017
Accepted 7 June 2017
Long-term studies focused on population size and
breeding parameters are essential to adequately
estimate population dynamics and demographic trends
of endangered species over long periods (Pandolfi et al.
2004, Thiollay 2006, Verdejo & López-López 2008,
Clutton-Brock & Sheldon 2010, López-López et al.
2012). The Lanner Falcon Falco biarmicus feldeggii is a
medium-sized raptor, which inhabits Mediterranean
dry and warm environments, composed by patches of
natural habitats (grassland and sclerophylous
vegetation) and agricultural land (arable and
agricultural land) (Di Vittorio et al.2015). In the mid-
20th century, the species suffered severe declines in
Europe, mainly due to poisoning, shooting and
trapping for falconry (Kemp & Marks 2017, BirdLife
International 2016). Habitat loss due to urbanization,
changes of agricultural practices, agricultural
intensification and afforestation have also caused a
reduction in hunting areas and prey species in Europe
(BirdLife International 2016). As a consequence, the
species is included in Annex I of the 2009/147/EC Bird
Directive due to small population size and very limited
geographical range (Birdlife International 2004).
In Italy, the Lanner Falcon is still threatened by illegal
shooting (Snow & Perrins 1998, Ferguson-Lees & Christie
2001) and by nest robbery (Di Vittorio et al.2015). This
species also suffers from other human activities, such as
rock-climbing and pesticide use, as well as from
collisions with electrical power lines (Gustin et al.2000).
Sicily holds the largest European population of the
Lanner Falcon (AA.VV. 2008,Sarà2008, Di Vittorio
et al.2015). The species extends its range also into
continental Italy (Andreotti et al.2008) and is classified
as ‘vulnerable’in the Italian Red list of birds (Peronace
et al.2012). A wide range of prey species (Massa et al.
1991), particularly Rock Doves Columba livia and
Magpies Pica pica are available throughout most of the
Sicilian range (Grenci & Di Vittorio 2004).
Despite all these threats, the Lanner Falcon remains
one of the least known species of European falcons,
© 2017 British Trust for Ornithology
CONTACT P. López-López Pascual.Lopez@uv.es Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/ Catedrático José
Beltrán 2, Paterna, E-46980 Valencia, Spain
BIRD STUDY, 2017
VOL. 64, NO. 3, 339–343
https://doi.org/10.1080/00063657.2017.1359234
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especially when it comes to population size and trends.
BirdLife International (2016) estimated that the
majority of the European population (430–830
breeding pairs) lives in Italy and Turkey, where a
moderate decline (20% in 12.8 years, two generations)
was detected in the recent past (1990–2000). The latest
national survey in Italy estimated between 140 and 172
pairs (Amato et al.2014). However, population size in
Sicily, one of the main strongholds for the species in
Europe, still remains unknown; estimates range from
up to 93 breeding territories regularly occupied during
the 2000–09 period (Sarà 2014), to 70–80 pairs
reported by Amato et al.(2014) and 65 pairs estimated
in 2014 by Di Vittorio et al.(2015).
The aim of this study is to report current population
size and breeding parameters of the Lanner Falcon in
Sicily, where the species has experienced a dramatic
decline in recent decades according to several studies
and confirmed as a result of our intensive field survey
(Di Vittorio 2007, AA.VV. 2008, Database Gruppo
Tutela Rapaci (GTR)). We also compare breeding
parameters with those obtained in previous studies in
the same island.
Methods
We created a starting database of Lanner Falcon
distribution obtained by compilation of three different
sources: (i) personal datasets of different Italian
ornithologists (Database of GTR); (ii) from the atlas of
terrestrial vertebrates of Sicily (AA.VV. 2008) and (iii)
from specific field surveys conducted in breeding
territories throughout the Sicilian range (Di Vittorio
2007, Di Vittorio et al.2015).
In 2016, a team of 20 experts was formed, thanks to
which a survey of all known territories of Lanner
Falcons occupied in the last 15 years was conducted. In
order to check site occupancy, to search for alternative
sites nearby and to compute breeding performance, all
territories were visited at least three times as follows:
(1) from late December to early March to check
occupation; (2) from mid-March to late April, during
the incubation stage to check egg laying and (3) from
early May to mid-June, during brooding and chick
fledging, to check pairs that raised young. Observations
were made using binoculars and terrestrial telescopes
at least 500 m from nesting cliffs to avoid disturbance
to the falcons. Given the habit of this bird to move
between nesting cliffs, in the cases of apparent absence
during the first visits, particular attention was taken to
secure the real absence of the territorial pairs or to find
the new nesting cliff by monitoring all cliffs in a radius
of 2 km of the known nest site. Nest productivity
(fledged young/checked pairs), flight rate (fledged
young/successful pairs) and breeding success
(successful pairs/checked pairs) were computed
following the standard methodology for raptors
monitoring (Steenhof & Newton 2007, López-López
et al.2007).
Mann–Whitney U tests and Monte Carlo
randomizations (9999 simulations) were used to
compare productivity recorded in this study with the
same parameters reported in a previous study carried
out in 2004 (Di Vittorio 2007 and unpubl. data) (N=
67 pairs). Analyses were computed in Past 3.0 software
(Hammer et al.2001). All tests were two-tailed and
statistical significance was set at P= 0.05.
Results and discussion
Overall, 126 territories were monitored, located
throughout Sicily (Di Vittorio 2007 and GTR
database). At least one individual Lanner Falcon was
present in 60 territories, whereas the remaining 66
were unoccupied. Most of the field surveyors
participating in this study did also survey the study
area for previous studies (AA.VV. 2008 and personal
databases of the authors), and therefore differences in
population size cannot be attributed to different
sampling effort. We were unable to estimate
reproductive performance in five territories and
another eight territories were occupied by only a single
individual throughout the breeding season. As a
consequence, these 13 territories were excluded from
the analyses.
In summary, we recorded 51 young fledged from 47
breeding attempts. Mean productivity (±standard
deviation) was 1.09 ± 1.18 fledged young/checked pairs,
flight rate was 2.22 ± 0.52 fledged young/successful
pairs and breeding success was 49.0%. We observed the
disappearance (probably due to mortality) of one of
the members of the breeding pair during the breeding
season in five nesting attempts.
Productivity was lower than compared with that
recorded in other studies in Sicily (Table 1), whereas
flight rate was similar to that reported by Salvo (1984),
Massa (1985), Iapichino & Massa (1989), Massa et al.
(1991) and Di Vittorio (2007). Our analyses showed a
significant reduction in breeding parameters between
2004 (Di Vittorio 2007 and unpubl. data) and 2016
(this study) (Figure 1): productivity (T= 738, z−3.927;
Monte Carlo P= 0.0001), flight rate (T= 3.18, z=
−2.680; Monte Carlo P= 0.0076) and breeding success
(T= 9.15, z=−3.062; Monte Carlo P= 0.0031).
Importantly, the proportion of successful nests
reported here (0.49; N= 47) is much lower than that
340 M. DI VITTORIO ET AL.
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reported by Ciaccio et al.(1987) (years 1981–84, 0.96, N
= 24), Massa et al.(1991) (years 1981–88, 0.94, N= 178)
and Di Vittorio (2007 and unpubl. data) (year 2004, 0.79,
N= 55). Another warning signal that could account for a
negative demographic trend of the species in Sicily is the
high number of territories occupied by one individual for
the entire breeding season or at least during part of it
(N= 13). This might suggest high levels of adult
mortality and low turnover rate (i.e. low replacement
by young individuals) possibly due to a scarcity of
floaters in the population.
The current situation of the Lanner Falcon in Sicily, as
elsewhere in Italy, is very fragile, since the species is
declining dramatically and it is evident in a decline in
productivity and in breeding success. Management and
conservation of the Lanner Falcon in Italy is complex,
as a result of the occurrence of coincidental factors
such as habitat reduction, agricultural intensification,
disturbance in breeding areas and nest robbery
operated by traffickers and falconers. In fact, a network
of illegal trafficking of chicks from nests and egg
robbery was discovered in Sicily in 2010. Similar issues
have reduced the population size of the Saker Falcon
Falco cherrug in Central and Eastern Europe (Horák
2000, Levin 2000, Moseikin 2000, Bailey et al.2001,
Galushin et al.2001, Karyakin 2001,2005,2008, Fox
2002, ERWDA 2003, Levin et al.2010). The robbery of
Saker Falcon nests for falconry purposes is considered
to be amongst the main reasons for its population
decline, in addition to an array of other negative
factors, including habitat degradation, increase of
anthropogenic pressure on natural sites, a worsening
food supply, disturbance, poisoning, electrocution and
direct persecution (Iankov & Gradinarov 2012).
To prevent nest robbery, it would be necessary to
organize nest guarding activities, especially in the most
at-risk sites, which are characterized by easy accessibility
to cliffs, a history of past nest robbery and territories
with low productivity over long time periods. In fact,
nest guarding has been shown to be a potential solution
to avoid this problem, yielding positive results in other
countries and for other raptor species (Bagyura et al.
2004, GTR unpubl. data). In addition, disturbance at
nest sites during sensitive parts of the breeding period,
either intentional or accidental, due to agricultural or
forestry activities, hunting, uncontrolled tourism, cliff
climbing, road construction, bird watching and
photography (Bagyura et al.2004,Beranet al.2012)
could be causing breeding failure and can cause nest site
abandonment (Di Vittorio et al.2015,S
aràet al.2016).
Table 1. Breeding parameters of Lanner Falcon recorded in Sicily
according to a range of studies, including this one.
Productivity
Fledged
rate
Reproductive
success
Number of
breeding
attempts Source
2.33 6 Mebs (1959)
2.40 9 Salvo (1984)
2.3 2.4 0.96 24 Ciaccio et al.
(1987)
2.1 2.3 0.94 178 Massa et al.
(1991)
1.69 2.31 0.91 70 Salvo (2001)
2.05 2.63 0.79 55 Di Vittorio
(2007) and
unpubl. data
1.09 2.22 0.49 47 this study
Figure 1. Comparison of breeding parameters for Lanner Falcons on Sicily between 2004 (Di Vittorio 2007 and unpubl.) and 2016 (this
study).
BIRD STUDY 341
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Another important cause of the Lanner Falcon
population decrease is habitat change, which is caused
by the rapid decline in traditional husbandry and
agriculture in hilly and rugged areas. As a consequence,
it is causing extensive habitat degradation, especially of
the characteristic cereal-steppe habitat selected by this
falcon within its Mediterranean range (Bassi et al.1992,
Leonardi 1994, Morimando et al.1997,Sarà2014,Di
Vittorio et al.2015). Maintenance of cereal steppes
habitats, promoting conversion to grassland, rotation of
culture and other traditional practices, while reducing
anthropogenic disturbance and infrastructure building
(Sarà 2014), could be alternative management strategies
to halt habitat degradation for Lanner Falcons.
Translated into conservation actions, this would suggest
selecting management strategies that favour a decrease
in abandonment of occupied territories (Sarà et al.
2016), increasing breeding success and encouraging
colonization of empty sites.
In conclusion, measures aimed at preventing
abandonment of occupied territories should be applied,
for example by developing a network of priority areas
to slow down the degradation of the pseudo-steppe
habitats by agri-environmental schemes (Sarà 2014).
Furthermore, management strategies should be
adopted to encourage occupation and territory fidelity
so as to increase breeding success (Sergio & Newton
2003) and recruitment by means of specific actions
(Jiménez-Franco et al.2011), such as (i) preventing the
illegal nest robbery and human disturbance near
nesting sites in the breeding season; (ii) reducing
potential high mortality of adults and juveniles (mainly
by shooting); and eventually (iii) development of a
captive breeding programme for the release of young
to facilitate the recruitment and occupation of deserted
sites in suitable areas.
Acknowledgements
We thank Gruppo Tutela Rapaci and Falcone S., Diliberto
N. and Mannino V. for field support during monitoring.
Two anonymous reviewers made valuable suggestions that
helped to improve the original manuscript.
Funding
This project was supported by the LIFE Project ‘ConRaSi –
LIFE14 NAT/IT/001017 CUP H86J15000240006:
Conservation of Raptors in Sicily’. P. López-López is
supported by a ‘Juan de la Cierva-incorporación’
postdoctoral grant of the Spanish Ministry of Economy and
Competitiveness (IJCI-2014-19190).
ORCID
P. López-López http://orcid.org/0000-0001-5269-652X
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