Ever since Algo and Polly have nested, I've wondered something, so here is a question for TPC or anyone else who may know:
Are there any health considerations for the species when a brother and sister mate and produce young? Or, for that matter, a mother & son such as at Winnipeg? (Not that we could do anything about keeping them apart. )
There isn't as a general rule. Nature has a way of taking care of problems. If there is some underlying genetic weakness, then the chicks won't survive (5 to 7 out of every 10 chicks die in the first year), in the meantime, a pair learns what to do and when one or the other doesn't return, that experience helps when they get a new mate. If there isn't an underlying weakness, then the adults add to their experience and the kids continue to contribute genes to the pool. Ivy had two mates prior to Princess - Jules was his preceding mate and they couldn't produce chicks to save their genetic heritage and they are totally unrelated (Jules isn't related to anyone here). As soon as he was paired with Princess, its been 4 chicks each year and not problems. Since Jules hooked up with Beau, four eggs every year and if she would refrain from nesting in "evil spots", then she would be working her way through the teens by now. So Nature takes care of her own one way or another.
Does that help?