Balancing the sex ratio

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cjc533
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Joined: 27 Apr 2020, 21:49
Location: London

Hey everyone,

I've recently read this article (linked below). In this, the researcher claims that Gouldian Finches choose the sex of their offspring based on the head colour of their male mate. Her findings suggest that pairs with matching head colours produce roughly equal numbers of males and females. Breeding pairs with different head colours over produce sons.

I'm wondering if any other breeders find this to be true? I myself find the opposite. I am inundated with female chicks at a ratio of around 3:1. My birds breed in an aviary and select their own partner. One BH, GB, PC SB male and RH, WC, GB, SB female are my most productive pair. On average she lays 6 eggs per clutch and chick mortality rate is exceptionally low for those two. In the last three years she's lost 2 chicks out of 33 raised chicks.
I also have a RH, YB, WC male and a BH, PC, GB female that over produce daughters. Their average egg count is lower and mortality rate is higher, 5 eggs per clutch and mortality rate around 15%. Of the 24 chicks these two have so far produced over the years, 19 have been female.

This same story is repeated throughout my aviary. Conversely, I do have two orange heads breeding together and they produce low numbers, often only raising two chicks per clutch - this year both were female!

Back to the study below - I wonder whether allowing females to choose their mate of their own free will plays a role in sex determination? In the study, although it doesn't say explicitly, it suggests that the pairings were researcher decided.

I'd love to hear your thoughts whether or not you're experiencing the same thing. If anyone can think of a reason why I'm getting so many females and what I might do to redress the situation, that would be appreciated. My Goulds are pampered and have absolutely everything they need! But I may be over looking something....

Pryke, S., & Griffith, S. (2009). Genetic Incompatibility Drives Sex Allocation and Maternal Investment in a Polymorphic Finch Science, 323 (5921), 1605–1607 | doi:10.1126/science.1168928.
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finchbreeder
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Joined: 27 Jun 2009, 20:00
Location: Midwest of West. Aust. Coast
Location: Midwest of West.Aust.Coast

If you put Gouldian finch in search up the top of the page, you may be able to find where this has been discussed before. Most of us have not found our results too closely reflect what the study did. Some of us keep our birds in mixed colour groups, some keep them in head colour selected groups. some breed 1 pair to an avairy. Most of us get more young cocks than hens. And most of us who breed with multiple pairs in an avairy, find as you have, that the dominant pair have the most young and so on down the pecking order to least or no chicks. Most of us are also green with envy at you getting more young hens than cocks.
LML
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garyh
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Location: Montrose, Victoria

i think you will find that all of her findings have been proved to be wrong,cheers garyh
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BrettB
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Joined: 13 Jun 2012, 23:28
Location: Perth

Hello cjc,
This paper caused quiet a stir in Australia, over a decade ago now. The findings seemed quiet at odds to what most Gouldian breeders had observed.
I would not go as far as Garyh, and say they have been proved wrong.
The population of finches used was very different to the highly domesticated forms of Gouldian that most of us keep.

To the broader question of whether hens can influence the sex of the progeny, this is also open to much debate.
There are lots of theories and not much evidence.
Lets just say it is theoretically possible, but the factors that influence it are complex.

Cheers
Brett
"We don't see things as they are, we see things as we are ." Anais Nin
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Nyala70
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Joined: 25 Sep 2021, 14:54
Location: Mindarie WA

Good day
Too many females ....!
I would have to say you are fortunate, hens are mostly in short supply ...

On a lighter note : My dad was a vet and did hobby - cattle farming on the side ...

He used to say to couples who had a newborn baby girl (instead of a boy as so many fathers and grandfathers were hoping for to carry the family name forward) :
"Well done ... a good bull produce mostly female(heifer) calves, you can build up your 'herd'!"

I think he said it to lift spirits if some whiff of disappointment where floating in the air & to pacify the father of the bride who felt his daughter could have done a bit better than this new son in law ...

Of course too many females is not ideal in the finch business 🙁 ... but you might have been a helluva cattle or sheep farmer😊!

I hope you can figure out how to change the sex ratio to a more acceptable balanced rate.
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