EEP Crowned pigeon number 4

EEP STUDBOOK CROWNED PIGEONS
Discussion about the results
This comparison gives only a rough indication about the differences about nutrition in the
wild and in captivity. First of all a lot of data submitted by the European institutions, were
incomplete, and some data could not be used. The data of the five institutions used, have not
been proved with those institutions and it might be possible that there is some bias. For
example, some institutions listed mineral stones and limestones on their list, while others did
not. In some institutions mineral stones are ad libitum available and they could have been
comitted or it might be difficult to calculate the eaten amount of mineral stones. A lot of diets
are not very accurate, because sometimes the amount fed instead of the intake was listed and
in most aviaries there are other birds (and unwanted animals like mice!) as well. Finally, no
questions were asked about seasonal influences in the diet of crowned pigeons. Of course also
in captivity there is variation in diet, caused by prices and availability of products like greens
and fruits.
The data from the crowned pigeons collected in the wild were collected shortly after the
reproductive season. It might be possible that during this period the intake of protein and
calcium is lower, to compensate the higher intake during the reproductive season.
Furthermore, only the crop and stomach contents of four crowned pigeons at only two days
and at two locations could be collected, so it is hardly possible to draw any scientific
conclusion from these data. The samples were collected in the summer of 1997, when it had
not rained for weeks, because of El Niño. Therefore the samples collected in Papua New
Guinea might not represent their “normal” diet. Furthermore the samples were put into
ethanol, immediately after taking them out of the bird (within an hour of being shot), and kept
under these circumstances for about two months before analysing them. It was not possible to
estimate the amount of dry matter within the food, because when removing the ethanol, also
some water, enclosed in the food, was removed.
Conclusion
According to observations from the field researcher of Rotterdam Zoo, and other sources as
well, it is known that they are feeding on seeds as well as on fruits. Most diets in captivity
contain a wide range of fruits, seeds, cereals, vegetables and so on. A bird in its productive
stage has other requirements than a bird, which only needs food for maintenance. A
productive bird has a much higher demand for calcium and magnesium. Although there is
much variation between diets in captivity and all institutions say that their birds are in good
condition, in most cases the breeding results are poor. Deficiencies in the diet of the birds
does not seem to have any visible effect on the birds. From this research project it turned out
that differences in nutrient availability might be a cause for the poor breeding results and
therefore more research into this topic is needed. The most striking difference between the
diet for crowned pigeons in captivity and the wild is the ratio of crude fibre. It should be
considered to supply the crowned pigeons with larger food parts, to stimulate the activities of
their gastro-intestinal tract. If more crude fibre and large mineral stones should be fed to the
birds, their gastro-intestinal tract would be more active, which will reduce stress and will lead
to more natural behaviour. Furthermore the amount of protein, calcium and phosphorus is
higher in captivity than in the wild and this can be a reason for the relatively high egg
production in captivity. Of course there are more factors which can have an influence on the
breeding results like zootechnic factors and stress.
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