Introduction.
Understanding genetics, mutations and modifications etc is a nightmare. However, having an understanding is a good tool to have for breeding better birds. I'm going to make a few very basic articles to help people understand things a little better. It's also a nightmare to talk about this subject whilst keeping it basic and easy to understand, so be gentle with me. I'm going to skip A LOT of the nitty-gritty parts out. Hopefully this way, it's easier to absorb and with the foundation set you can then read into the subject(s) further to broaden your knowledge. For the purists out there, yes I have cut some things out, and missed what may seem to be relevant information, but I'm trying to keep it SIMPLE. Anyway, enjoy and if there's demand for it, i'll write a few more.
I strongly urge everyone to get a copy of "Lovebirds Owners Manual and Reference Guide" written by Dirk Van den Abeele.
It covers everything I am going on about but in much more detail and with much more precision.
More info on his website http://www.agapornis.info/english.htm
Hmm, a feather.
Before learning about the magic that happens inside a feather, I suppose we should go over the relevant feathers and their features first?
A contour feather is the most important feather (well, for now it is!), because it’s the one that is responsible for the majority of colour we see on an Agapornis.
Boring picture? Ok...
- We have the feather shaft.
- Coming off the shaft we have the barbs.
- Coming off the barbs we have barbules.
- Coming off the barbules are barbicels (also known as hooklets).
Interestingly, the barbicels are pretty much what hold the feather together. They interlock and keep it tight and smooth. When our birds are preening, they are basically making sure these are all in place so their feathers look sexy.
The magic that goes on inside a green feather.
To understand what happens inside a green feather, we need to look at a cross-section. What’s a cross-section? Well, cut through a barb then look inside it with either super-human eyes or a microscope. You will see something that probably looks nothing like my diagram, but my diagram is much easier to understand.
Yeah ... I’m guessing that picture does not mean much at the moment. Let’s explain it...
There are 2 pigments that play an important role in this process.
- - eumelanin: - a dark pigment (black) -
- -psittacofulvin(psittacin): - a coloured pigment (various colours from red to yellow)
Psittacofulvin is a beast of a word, it actually scares me a little.
It’s a nightmare to spell correctly let alone pronounce it right. Call it psittacin to make it easier.
I believe you pronounce it “sit-a-cin”. Eumelanin is pronounced “you-mel-a-nin”.
Ok let’s get down to business. The diagram above is showing what is inside the barb of a feather. If you have already forgotten what the barb is, then you obviously never read the first part properly or you have a terrible memory. Either way, you could be in trouble here lol.
Cortex.
The yellow ring is the cortex. This part contains yellow psittacin pigment.
Spongy zone.
This space is colourless keratin that has a texture similar to, believe it or not, a sponge.
Eumelanin.
That black pigment we just talked about.
Medullary cells.
Errm, something that’s not really worth talking about here, so forget them for now.
So we have the pigments in place now we just need to figure out how the feather becomes green from yellow and black pigment. Well, it’s all about light!
Daylight has no colour, it’s a neutral light that we can’t really see, even though it’s made up of various coloured waves of light. This daylight lands on the barb of the feather. It is attracted to the eumelanin inside the barb. When the light reaches the spongy zone, interference occurs. Basically the light has a little disco, it starts going a bit mad until it is reflected as a blue coloured light. This blue coloured light, combined with the yellow psittacin in the cortex gives us a green coloured feather. Blue + Yellow = green.
To recap on that:
- Neutral daylight is attracted to the eumelanin in the barb of the feather.
- Interference in the spongy zone causes the light to reflect as a blue coloured light.
- Blue light combined with yellow psittacin pigment gives a green coloured feather.
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