In David’s note, presumably the other parent is a normal Crimson Rosella, not a normal Eastern Rosella. I think most of these hybrids we find, associate with
Crimson Rosellas more than Eastern Rosellas.
Someone posted an odd rosella a few weeks ago that I suggested I think would have been a second generation (CR) hybrid. This matches David’s note.
This is based on that I do not share the understanding that hybrid rosellas are infertile. Certainly there are extensive hybrid colonies among lorikeets, so
hybrids there are clearly fertile. Why are rosellas different from lorikeets? Rosellas appear less likely to form these hybrid colonies.
Depending on semantics, that issue can alter the question as to where do you draw the line as to what is a species.
Whether or not hybrids of similar species are fertile or not, ranges from yes to no through the possible range of diminished fertility. It is convenient to
say that hybrids are not fertile (like a mule) and that is proof to separate the species. But not everything is convenient. There are many possible reproductive isolating mechanisms. Main feature is whether the unmatched different parent chromosomes are sufficiently
similar to line up and then separate correctly during meiosis. It does not need to always happen with the same result. Quite possibly the situation in birds is more complex with more possible outcomes, than in mammals because birds typically have a much higher
number of chromosomes than mammals.
From: Martin Butterfield [
Sent: Thursday, 24 October, 2019 9:52 AM
To: David McDonald (personal)
Subject: Re: [canberrabirds] Hybrid rosellas ...
I recall Dick Schodde commenting, when showing COG members around the NWC - some years ago - that he had collected a pair of hybrids that were fertile.
On Thu, 24 Oct 2019 at 09:41, David McDonald (personal) <> wrote:
Greetings. One of my neighbours has a hybrid Crimson/Eastern Rosella. He has seen it feeding an immature crimson.
My understanding is that hybrid rosellas are infertile. Grateful for any correction to this understanding, or other suggestions as to what may be going on here.
Best wishes - David
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Wamboin NSW 2620
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