I have a PDF copy of the paper below:

Evolution of host egg mimicry in a brood parasite, the great spotted
cuckoo

Authors: SOLER, JUAN J.1; AVILES, JESUS M.; SOLER, MANUEL2; MØLLER,
ANDERS P.3

Source: Biological Journal of the Linnean Society, Volume 79, Number
4, August 2003 , pp. 551-563(13)

Publisher: Blackwell Publishing

Abstract:
Brood parasitism in birds is one of the best examples of
coevolutionary interactions in vertebrates. Coevolution between hosts
and parasites is assumed to occur because the parasite imposes strong
selection pressures on its hosts, reducing their fitness and thereby
favouring counter-adaptations (e.g. egg rejection) which, in turn,
select for parasite resistance (e.g. egg mimicry). Great spotted
cuckoos (Clamator glandarius) are usually considered a brood parasite
with eggs almost perfectly mimicking those of their host, the magpie
(Pica pica). However, Cl. glandarius also exploits South African hosts
with very different eggs, both in colour and size, while the Cl.
glandarius eggs are similar to those laid in nests of European hosts.
Here, we used spectrophotometric techniques for the first time to
quantify mimicry of parasitic eggs for eight different host species.
We found: (1) non-significant differences in appearance of Cl.
glandarius eggs laid in nests of different host species, although eggs
laid in South Africa and Europe differed significantly; (2) contrary
to the general assumption that Cl. glandarius eggs better mimic those
of the main host in Europe (P. pica), Cl. glandarius eggs more closely
resembled those of the azure-winged magpie (Cyanopica cyana), a
potential host in which there is no evidence of recent parasitism; (3)
the appearance of Cl. glandarius eggs was not significantly related to
the appearance of host eggs. We discuss three possible reasons why Cl.
glandarius eggs resemble eggs of some of their hosts. We suggest that
colouration of Cl. glandarius eggs is an apomorphic trait, and that
variation between eggs laid in South African and European host nests
is due to genetic isolation among these populations and not due to
variation in colouration of host eggs. © 2003 The Linnean Society of
London, Biological Journal of the Linnean Society, 2003, 79, 551-563.