Raptors are considered to pose one of the greatest aviation bir
d strike risks. We
investigated raptor bird strikes reported at the largest Spanis
h airport (Adolfo Suárez Madrid
Barajas; AS-MB) from 2009 to 2016 to determine the factors cont
ributing to the increased
incidences and develop recommendations to mitigate the risks. W
e hypothesized that
increased raptor bird strikes resulted from changes in foraging
and dispersal patterns of Iberian
Peninsula vultures (
Aegypius
spp. and
Gyps
spp.) after 2004–2005. We used information on
raptor bird strikes obtained from offi
cial databases and published studies, reported incidences
of raptor bird strikes and their characteristics (i.e., time, l
ocation, species involved), data
collected about raptor fl ight heights, and estimates of relativ
e abundance of large raptors
and their prey species obtained through standardized surveys co
nducted in the high priority
aviation area around the airport to assess bird strike risks. O
ur fi eld work was conducted from
June 2014 to May 2016. We confi rmed a direct relationship betwe
en the relative abundance
of the raptors studied and their prey species in the priority a
viation areas. Raptor bird strike
risks increased during spring and summer when food sources were
abundant in locations
where fl ight altitudes of aircraft were <1000 m above ground le
vel. Our observations appear
to be related to European Union sanitary policies that altered
the availability and occurrence
of livestock carcasses. These changes
may have increased the ov
erall movement of vultures
in search of new, scarcer, and more distant food sources, enhan
cing the likelihood of overlap
with air traffi
c corridors. Although further studies on aviation risk are ne
eded, our results
suggest the need to implement immediate remedial management act
ions to alter vulture
habitat quality by reducing food sources in sensitive areas, an
d providing alternative food
resources at distances suffi
ciently far from commercial airports
This work was carried out within the framework of the project “Guidelines for the prevention of large soaring bird-strike hazard in relation to air safety,” commissioned by the Spanish Ministry of Environment (MAPAMA) and developed by TRAGSATEC. It is part of the collaboration between MAPAMA, the State Air Tra ffi c Agency (AESA) and the company managing air navigation and airport operations of the Madrid airport (AENA). J. Sánchez performed most of the fi eld work, and M. Abascal, D. Muñoz, R. Martínez, L. M. González, and V. García helped in di ff erent phases. The AENA provided essent ial data on collisions and observations of birds from aircraft around AS-MB airport, and we are most grateful to C. González, M. M. Anda, and S. Alonso. The Comunidad de Madrid administration authorized the implementation of the project and issued permits for raptor monitoring. The comments of 4 reviewers as well as T. DeVault, HWI associate editor, and T. Messmer, HWI editor-in-chief, greatly improved the previous drafts of the manuscript. Our research was supported by a Ramón y Cajal research contract by the Ministry of Economy and Competitiveness (RYC-2012-11867).