EEP Crowned pigeon number 4

EEP STUDBOOK CROWNED PIGEONS SUMMARIES
1.5 Recommendations for ex situ management
A crowned pigeon EEP Species Committee meeting chaired by species coordinator Ing. Joeke
Nijboer (Rotterdam) was held in 1997. It was agreed that the EEP would offer to take the
seven remaining Goura scheepmakeri in North America as suggested by the crowned pigeon
SSP. It was also agreed that a location to experiment with pair formation within a group of
crowned pigeons would be searched for, as reproductive results might improve if the birds
were given the opportunity to choose their own mates. It was suggested that the incoming
group of Goura scheepmakeri would provide a good opportunity to make an attempt. It was
proposed that the U.K. would focus on Goura victoria (Bolton, 1997).
Nest heights: a pair of Goura victoria nested 3 - 4 m from the ground level when the choice is
given, while a pair of Goura scheepmakeri at Copenhagen Zoo nested 2 - 2.5 m from the
ground when given a free choice (Bolton, 1997).
The goal for a breeding program for crowned pigeons determines whether seperate breeding
programs for sub-species are required. If re-introduction of captive-born individuals into the
original populations belongs to one of the topics in the future, even each island-form of the
common crowned pigeon should be bred in separate enclosures. Hybridization of sub-species/
populations might be allowed when preservation of the captive population or introduction
under semi-wild conditions are the only options.
In the latter case, it is merely a matter of opinion where zoos show "pure" forms or a lookalike
of a species. Hybridization will probably not result in outbreeding depression, which can
occur when sub-species or populations are so genetically different that hybridization will
result in offspring with reduced fitness (Templeton, et al., 1986).
Outbreeding depression is expected to occur when isolated populations are genetically
adapted to specific conditions in their environment. Since the (sub-)species of crowned
pigeons seem to inhabit the same type of environment, special genetic adaptations are not
expected. The three species of Goura seem not to differ in chromosomal features (De Boer
and Belterman; Belterman and De Boer in Assink, 1988). Recent DNA-research (Bohmke and
Patton in Wetzel, 1991) proved that the DNA pattern of the three species are so much
different from each other, that the DNA pattern does not point to different sub-species, but
must be considered as three species.
The close affinity of the "pure" species, indicates that the period of isolation of their islandforms
might be too short to develop large genetic differences (Assink, 1988). Assink
suggested maintaining a breeding program for Goura victoria and also one for Goura cristata
and don’t differ between the sub-species. The differences between the two subspecies of
Goura scheepmakeri are larger, so he would like to start separate breeding programs for each
subspecies of Goura scheepmakeri, but the low number of both populations does not allow a
division into two breeding populations (Assink, 1988).
The breeding success of crowned pigeons in captivity is low in comparison to the number of
offsprings they can produce theoretically. It is important to know how many birds are
required to maintain viable populations.
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