Kakapo nutrition confirms what we all suspect

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GregH
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I came across an alert from New Scientist magazine concerning the Kakapo (the rare flightless parrot from New Zealand). The article Vitamin supplements could save critically endangered kakapo is based on a paper from the Journal of Steroid Biochemistry and Molecular Biology. In it the author tells how food the present supplements given to the birds are killing the populations with kindness by feeding too many calories which skews the sex ratios in favour of male kicks and that when too much protein is given the birds, their appetite is curtailed and so don't take in enough calcium to form eggshells and bones. This is the first mention I've seen that gives some explanation of the skewed sex rations in captive birds fed ad libitum. Which aviculturists don't complain about having fledged too many males? If they are on this forum please tell us how you do it. To overcome the calcium problem in Kakapos the author found increasing vitamin D in their supplementary foods increased calcium absorption and overcame any deficiency in the population. Calcium deficiency can result in poor nerve signalling and muscle tone, broken ones, egg binding and death. Getting nutrition right for critically endangered birds is essential and there are now many exotic finch species whose captive population are critically endangered here in Australia. We need more investigations like this.
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elferoz777
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Thanks for sharing.

Your posts always interest me. Ill now attempt to decipher the articles
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finchbreeder
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Sounds like we all need to go and top up the cuttlefish, and other calcium sources in our avaries. Wonder if anyone with good captive breeding records has ever thought to record which birds seem to eat what to the degree that you could work out why one pair has more hens, one has even numbers and one more cocks? Thanks for the alert Greg.
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casehulsebosch
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the determination of the sex in Gouldian young has already been scientifically explored and reported on by Sarah Pryke.

Cheers, Case,Tauranga, New Zealand.
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GregH
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Sex allocation is a complex phenomena. In birds, this is determined by the karyology of the female's gamete rather than the male as in mammals or incubation temperate in many reptiles or ploidy level (chromosome number) in insects. In Gouldians Dr Pryke's group found that "changes in maternal corticosterone levels during stressful situations, such as the quality of a breeding partner, may provide an endocrine mechanism that can be exploited for strategic sex allocation". What that means is that a hen exposed to a stress, such as mate mismatch for head colour (linked with temperament) or overcrowding, can and does skew the resultant broods sex ratio, in this case in favour of males. Pryke's group went further to show that cortisol inhibitors reversed this situation and could reverse the gender bias in favour of females. In the case of the kakapo a poorly balanced diet containing an excess of calories compared to other nutrients is a stress that skews the sex ratio in favour of males as Pryke's group predicted.
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BrettB
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Interesting article Greg, unfortunately I don't have access to the full paper.

Studies like these show how complex nutrition is and how we still have a lot to learn about the impact of different diets.
It also highlights the significance of Vit D

Most people know Vit D as the Vitamin you get from sunshine, but how do nocturnal animals and birds get enough?
I have never really considered that

Cheers
Brett
"We don't see things as they are, we see things as we are ." Anais Nin
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