A Rocha Portugal Observatory Report 2009-2010

6 A Rocha Portugal Observatory Report 2009-2010
Introduction
THE GREAT SPOTTED CUCKOO, CLAMATOR GLANDARIUS, IN THE RIA DE ALVOR STUDY AREA
Willem Scheres
The Great Spotted Cuckoo, Clamator glandarius, is a brood-parasite that occurs in several populations in
Africa and in the Mediterranean Basin. In Iberia it prefers open woodland of Stone Pines, Pinus pinea, and
heathland interspersed with Cork Oaks, Quercus suber. It also favours cultivated areas such as olive and
almond-groves (Cramp, 1985).
In the Iberian Peninsula the Great Spotted Cuckoo parasitizes mainly on the Magpie, Pica pica, and
occasionally on other Corvidae like the Carrion Crow, Corvus corone, the Raven, Corvus corax, the Jackdaw,
Corvus monedula, and the Chough, Pyrrhocorax pyrrhocorax, according to Arias de Reyna (1998). However,
it is not known to parasitize the nests of the Azure-winged Magpie, Cyanopica cyanus, which is a common
species in the southern half of Iberia and also belongs to the family of the Corvidae. Extensive field-studies
including detailed monitoring of many inhabited nests did not show any case of an Azure-winged Magpie
parasitized by the Great Spotted Cuckoo (Valencia, 2005). Another species that, according to Cramp (1985),
is visited by the Great Spotted Cuckoo is the Hoopoe, Upupa epops.
In Portugal the Great Spotted Cuckoo is a scarce migrant breeder and a scarce passage migrant occurring
from February to August (Moore, 1997). It is more common in the interior parts of Portugal than along the
coast and it parasitizes on the Magpie and the Carrion Crow (Rufino, 1989). It is a rare breeding bird in the
Tejo Estuary south of Lisbon and is also recorded during the period February – August (Leitão, 1998).
This article describes and comments upon the presence of the Great Spotted Cuckoo in the field-study area
of Quinta da Rocha between 1984 and 2010. Observations have been taken from the A Rocha Observatory
Reports and from the Observatory Birdlog.
The presence of the Great Spotted Cuckoo within Quinta da Rocha
The Great Spotted Cuckoo is a very scarce visitor to Quinta da Rocha. In total there are 19 records of this
bird species in the period 1986 - 2010. These records are spread over the 8 months between January and
August. It is most frequently seen in February, with 5 records, and in March, with 3 records. In autumn and
the first month of winter, December, they are not recorded at all (see Figure 1). The single record in
January relates to a wintering individual.
Cramp (1985) mentions that, with the late departure of some juveniles and the early appearance of the
spring vanguard, the Great Spotted Cuckoo may be absent from the Mediterranean Basin for only a few
weeks around midwinter. The sighting of 11 January 2002 is a significant midwinter record.
According to Cramp (1985) the return movement to southern Spain is from early February. Five records in
the study area were made in February, thus corresponding with early returning birds.
Mainly juveniles were seen during the months of June, July and August: 5 of the 6 records are related to
juveniles (see Table 1). This was also the case in Southern France in the Valleé des Baux close to Arles. The
author saw only juvenile Great Spotted Cuckoos on three successive days during a visit in July 2006 to the
French A Rocha Centre at Les Tourades, which is situated in this same valley.