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Relationships between the Great Spotted Cuckoo Clamator glandarius and Its Corvid Hosts in a Recently Colonized Area
Ornis Scandinavica (Scandinavian Journal of Ornithology)
Vol. 21, No. 3 (Sep., 1990), pp. 212-223
Stable URL: http://www.jstor.org/stable/3676781
Page Count: 12
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Near Granada, southern Spain, Great Spotted Cuckoos Clamator glandarius used four corvid species as hosts, and in the Magpie Pica pica the rate of parasitism was significantly higher than in other areas. Removal of host eggs by the parasite was never observed, but damaged eggs usually existed in parasitized nests and the most damaged ones were removed by the host. Frequently more than one cuckoo egg was laid per nest and sometimes clutches had eggs from more than one female. I carried out 85 experimental egg manipulations. Rejection was found only in Magpies. Real parasite eggs were not rejected in the Guadix and Hueneja areas. The eggs of the four host species are larger than those of the parasite but incubation was nevertheless effective. The size of Great Spotted Cuckoo eggs did not vary significantly among different parasitized species, and their coloration was the same independently of host species and never mimetic (except for the Magpie). Fledging success of the Great Spotted Cuckoo was twice as high when it parasitized Magpies as when it parasitized Carrion Crows Corvus corone. The first and second parasite eggs were more successful than the third, and the egg of a second female parasitizing a nest had significantly lower hatching and breeding success than the first female's. Eggs deposited early in the laying period produced more chicks than those laid late and than those deposited when the clutch was completed. Great Spotted Cuckoo parasitism had little influence on the breeding success of the Carrion Crow, but had a strong negative impact on that of the Magpie. Differences in parasite adaptations of Great Spotted Cuckoo and European Cuckoo Cuculus canorus are discussed.
Ornis Scandinavica (Scandinavian Journal of Ornithology) © 1990 Nordic Society Oikos