AN UPDATE OF THE BREEDING AND WINTERING POPULATIONS
OF RED KITE (Milvus milvus) IN EXTREMADURAJ. Caldera, A. Sánchez, J.M. Abad*, E. Jiménez and S. Pérez
Servicio de Conservación de la Naturaleza y Áreas Protegidas. Consejería de Medio Ambiente y Rural, Políticas Agrarias y Territorio. Junta de Extremadura. Av/ Luis Ramallo s/n, 06800
Mérida (Badajoz) Spain. *Contact: [email protected]
INTRODUCTION
The red kite (Milvus milvus) is classified as “near threatened” at European and global scales, with their core populations experiencing a rapid decline (Birdlife International
2015). In spite of this trend, European northern populations are increasing and it has been pointed out that they could outweigh declines of core populations (Birdlife
International 2013). Decline of the populations of Germany, France and Spain, that historically have accounted more than 75% of the global population, have been attributed
to a high mortality on the France and Iberian wintering grounds, mainly due to direct illegal poisoning and indirect poisoning from pesticides and rodenticides (Smart et al.2010). These factors could also heavily influence the rapid decline of the Spanish breeding population, estimated at 46% in the period 1994-2004 (Cardiel 2006). In that same
period, the breeding population of Extremadura (SW Spain) has experienced a sharp decline (60-70%).
Here, we present the results of the last censuses of the breeding and wintering population in Extremadura.
MATERIAL AND METHODS
Red kite wintering population were surveyed in nocturnal roost sites along Extremadura in winters 2013-2014 and 2014-2015. An effort to locate new roosting sites were done
along all the region and afterwards all them were counted within 7 days to avoid repeated counts. On the other hand, breeding population were estimated in the year 2015
using road transects following the methodology of previous national census (Viñuela et al. 1999). Briefly, 10x10 kms UTM squares were selected scattered across the regional
range of the species and road transects were conducted between May and mid July. We have included in the analysis all the 10x10 kms UTM squares with transects of at least
20 kms.
RESULTS
During the winter censuses a total of 89 ( 46 in Cáceres and 43 in Badajoz) and 76 (35 in Cáceres and 41 in Badajoz) roosting sites were surveyed during the 2013-2014 and
2014-2015 winter periods. Of them, 53 (27 in Cáceres and 26 in Badajoz) in 2013-2014 and 44 (22 in Cáceres and 22 in Badajoz) in 2014-2015 were used by 5243 and 5668
red kites (Fig. 1A), respectively.
During the breeding season 2015, a total of 9437.7 km in 239 10x10 km UTM squares were surveyed (Fig. 1D). The estimates for the breeding population of the whole
territory were 207 breeding pairs, 75 in Badajoz and 132 in Cáceres (Table 1).
Table 1.- Results of the breeding census 2015. 10x10 UTM squares: total (censused).
District10x10 km
UTM squares
Distance
driven (km)
No. of red
kites
Estimated
breeding pairs
Dehesas Suroeste 28 (19) 978.9 6 15
Llerena‐Azuaga 22 (1) 72.1 0 0
Noroeste 22 (17) 805.8 0 0
Serena 27 (10) 399.6 4 18
Sierra Sur 15 (8) 404.9 0 0
Sierras Noreste 21 (12) 440.4 0 0
Tierra de Barros 18 (6) 248.8 1 8
Trancha‐Hornachos 14 (6) 499.5 0 0
Valles Noreste 15 (11) 467.5 1 6
Vegas del Guadiana 30 (11) 449.4 3 16
Zafra 22 (6) 239.0 2 12
Badajoz 234 (107) 5005.89 17 75
Alcántara 7 (4) 137.2 2 6
Brozas‐Cáceres 17 (6) 218.5 2 11
Coria 23 (18) 635.8 12 22
Hurdes 5 (2) 70.5 0 0
Llanos 17 (9) 358.5 6 14
Monfragüe 13 (11) 343.5 4 8
Montaña 3 (1) 25.8 2 9
San Pedro‐Montánchez 22 (15) 650.6 5 13
Sierra de Gata 6 (6) 166.4 2 4
Suroeste 10 (3) 78.1 0 0
Tietar‐Navalmoral de la Mata 18 (15) 521.3 8 15
Trujillo‐Jaraicejo 8 (4) 111.3 0 0
Valle de Ambroz‐Alagón 18 (14) 434.7 16 24
Valle del Guadiana 10 (3) 101.2 1 6
Vera‐Jerte 10 (7) 190.9 0 0
Villuercas‐Guadalupe 25 (14) 387.5 0 0
Cáceres 212 (132) 4431.762 60 132
Extremadura 446 (239) 9437.7 77 207Fig. 1.- (A) Counts of the roosting sites, (B) results of the road transect winter census, (C) estimates of the regionalbreeding population and (D) coverage of the 2015 census and positive 10x10 km UTM squares. Source: a Cardiel (2006);b Viñuela et al. (1999); c SEO/Birdlife (2014a); d SEO/Birdlife (2014b)
DISCUSSION
According to the data obtained in previous winter census using road transects (Fig. 1B), the regional wintering population of the red kite have recovered the levels of the I
National Census 1993-1994 (Viñuela et al. 1999). This data, together with roosting site counts (Fig. 1A), showed that the wintering population in the province of Badajoz had a
higher increase than Cáceres. The same trend have been shown in the breeding estimates, with the population in Badajoz increasing by 82% and in Cáceres decreasing by 45%
in the period 2004-2015. This increase should be taken with caution because some areas, as La Serena and Tierra de Barros, had no or low coverage in previous census, but
also, it could indicate that some factor may influence differently the population of the species in each of the provinces. In any case, urgent measures should be taken to
determine the factors that caused the sharp decline (71%; Fig. 1C) of the regional breeding population in the period 1994-2015.
REFERENCESBirdLife International. 2013. Milvus milvus. The IUCN Red List of Threatened Species 2013: e.T22695072A40741496.http://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T22695072A40741496.en . Accesed on 15 October 2015BirdLife International. 2015. European Red List of Birds. Office for Official Publications of the European Communities. LuxemburgCardiel I. 2006. El Milano real en España. II Censo Nacional (2004). SEO/Birdlife. MadridSEO/Birdlife. 2014a. Actualización de la población invernante de Milano real (Milvus milvus) en la Red Natura 2000 de Extremadura. Ineditreport for the Junta de Extremadura.SEO/Birdlife. 2014b. Actuaciones para la conservación del Milano real en Extremadura y su plan de recuperación. Inedit report for theJunta de Extremadura.Smart J., Amar A., Sim I.M.W., Etherridge B., Cameron D., Christie G. and Wilson J.D. 2010. Illegal killing slow population recovery of a re-introduced raptor of high conservation concern- The red kite Milvus milvus. Biological Conservation 143(5):1278-1286.Viñuela J., Martí R. and Ruiz A. 1999. El Milano Real en España. Monografia nº6. SEO/Birdlife. Madrid
ACKNOWLEDGEMENTSWe are greatly grateful to Environmental Agents andtechnicians of the Junta of Extremadura and AEMA fortheir great effort performing the census of red kites.Gloria Cortázar and Maria Arredondo processed field datafrom the winter census.
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