El milano real en España. II Censo Nacional (2004) - SEO/BirdLife

Red kite in Spain
SUMMARY
For the second time, SEO/BirdLife has undertaken a national census of the red
kjite.The methodology applied in this document is the same as used in the 1992-
1994 census for breeding and wintering populations of the red kite. At that time,
the car transects method was considered the most suitable for this purpose, given
the effort/results ratio for the specific topography of the Iberian peninsula,
and the species behaviour. The search for roosting places in winter and for
breeding territories in the reproductive season was also carried out. In this way,
the methodology was not only the most appropriate for the species, but also ensured
that the results of the two censuses could be compared, thus obtaining the
population trends for the red kite.
The wintering population has been calculated on the basis of the total estimated
per province, minus the number of resident red kite individuals (nr. of breeding
individuals plus 1/3 of juvenile population) The breeding population was estimated
by calculating the number of pairs on the basis of the transect data and assuming
that 1/3 of the population is made of young individuals.
Wintering population census
The census has covered a large area of the wintering range of the red kite. Approximately
41% of the quadrats in provinces with wintering records for the
species (figure 1) have been surveyed, including trips along 28,416 km of trails,
paths and roads.This detected 5,541 red kite individuals and obtained an overall
kilometric abundance index (KAI) of 19.50.
The results of the second national wintering census of red kite show a decrease
close to 50% in the bird numbers just within 10 years. Such a decrease is due to the
overall decline in the Northern European population of red kite (BirdLife, 2000),
which winters in Spain, and also to the dwindling breeding population that resides
in our country (Viñuela, 2004). The final estimates for the wintering population in
Spain, according to the 2004 census, amount to 35,523-36,233 red kites, whilst the
numbers for the 1994 campaign were 66,235-72,165 (table 3,Viñuela, 1999).
The values in the winter census reveal a negative trend for the wintering population
all over Spain, except for Navarra and Madrid, where the wintering numbers
remain stable, and the Basque Country and Catalonia, where an increase
has been recorded (figure 2).
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