Suns and Jendays are considered one species that's starting to split in it's natural range. It's very hard to explain without going into the details of spe******ation and adapting to environments, reproductive isolation and how new species are formed ect, but try to think of it as this. A dog and a wolf are both canines, can and do interbreed when they encounter each other and have fertile offspring so are still technically still of the same species or very very closely related species (just like how suns and jendays can mate and produce fertile offspring. Fertile being key here) , but due to different conditions (n this case, domestication, in the case of suns and jendays, different environments), they are different. They all belong to the species of Canis lupus but Domestic dogs are a SUBspecies of that species. Domestic dogs are
Canis lupus familiaris (and C.L dingo) both of which are offshoots of Canis Lupus.
If natural selection and evolution was allowed to happen for a few thousand years, eventually both types would continue to adapt to their environments and become so different they can no longer interbreed (usually they are separated by say a mountain range and cant get close enough to swap genes or one group of the original species is swept away in a storm and colonises a new area where they are separated from the original group etc) and should they come together again they are no longer the same, no longer can breed together (or produce fertile offspring together, horses and donkeys can breed together and have foals, but the foals are infertile) and hence are now separate species as their genes are isolated from each other.
It's very hard to explain unless the person your explaining to has a good basic knowledge of biology and evolution, so I hope that made sense! The lines between species are not as clear cut at "thats a dog, thats a cat" sometimes it is "Their both different, but not different enough to be separate!"
But onto suns and jendays!
Jenday conures are known scientificly as
Aratinga jandaya and sun conures as
Aratinga solstitialis but both belong to the
Aratinga solstitialis complex which includes the:
Jandaya Parakeet,
Golden-capped Parakeet, and
Sulphur-breasted Parakeet. Usually these three are considered sub species of the sun conure (like how the domestic dog above is a sub species of the wolf, it's parent species) but some think they are separate species, and some people think Sun and Sulphur-breasted Parakeet are the same species, and the Jenday Parakeet and Golden-capped Parakeet another species. Regardless they are all part of the
Aratinga solstitialis complex which means they are all closely related and in the wild can (and do sometimes) still are capable of breeding with each other and producing FERTILE offspring. Think of sunday conures!
As for temperamental differences between sund and jendays? Both are LOUD. The lady I got Alex off has two pairs of suns, and in my experience with them they have a shriller, more piercing call then the jenday, although they are both the same volume. Apart from that the only real difference I have encountered with them is colour. Alex (and his sister who still lives with his breeder, Im good friends with them so I see them often) are calmer then their suns and less excitable, but that's just my observation.
So I guess suns are abit prettier with all the yellow, but jendays are a little less ear piercing (its still pretty bad) so take your pick! They are both very similar.
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