finchbob wrote:Er, any truth in this? I only just got into breeding gouldians and I pair them up with different colour heads. One pair is breeding so far, they laid 6 eggs, 1-2 hatched and they chucked the rest. They've since laid another 6 eggs and are incubating.
Re-arranging all my pairs to match head colours just because of a video seems a bit off.
You have to remember that Dr. Pryke is working with hundreds of pairs, and her observations are reflected in large numbers of offspring from those pairs in her research facility. She is also only working with Red and Black head color morphs because Orange is so incredibly scarce in the wild, and she does not do research on the mutations.
Like anything else, statistics and scientific research require you to replicate a lot of things numerous times in order to quantify what you are seeing.
Just because in her research, she is seeing a pattern of biased sex ratios in offspring of mis-matched pairs, doesn't mean that you will necessarily see it if you mis-match yours.
One pairing will only produce three-four clutches..
Now talk about 100 pairs and the number of clutches they will produce - you have a LOT more to look at it.
It is similar to thinking about a coin toss.. the odds are "50/50" - but if you only flip it four times, you could very likely get heads every time.
Flip it 10,000 times, and you will have a more even 50/50 distribution of results.
I recently mis-matched a BH male to a RH female..
Technically this pairing should result in more males to females..
In the first clutch I had 5 out of 5 fertile eggs that all hatched - three are female, two are male
However, in past clutches of mis-matched head colors (BH male to RH hen), I got 8 males and two hens, and in yet another (OH male to RH hen), I didn't get a single hen.
Odd? A little..
Could it be coincidence? Yes..
Am I going to base my pairings on this research? Obviously not
There are many other factors to consider besides head color.. other research suggests that if a hen really likes her mate, she will bias the offspring to be males to put more males like her mate into the population.
Others say a hen in prime breeding condition will produce a higher ratio of male offspring.
Still others feel that lighting plays an important role because Goulds see in an additional dimension (UV) of color, so if the lighting is off, it could affect mate selection.
Not to mention there are a slew of other factors that go into mate selection (beak size, tail spire length, song and dance - and the males do have some preferences of their own).
Keep in mind many of us are
not breeding in a large colony setting where the birds are allowed to select their own mate based on their preferences.
If we breed in individual cages with the pairs separated outside of breeding - we are
selecting the pairs for them and giving them no other option. So we are acting on the birds and we are an additional variable in the equation.
Tossing doesn't reflect a head color preference, and in my experience it is
usually the male that tosses, and since it is technically the females that have the higher preference on head colors, it seems unlikely that this behavior would be related.
I find tossing to be either a problem of inexperience, or an intrinsic behavioral problem that may never go away.
Although it has been mentioned here before that it is not like she had any other choices. 