|male Caspian Stonechat ssp.armenicus|
|Back on view; this bird showed a nice whitish unstreaked rump and when in normal posture perched, just a hint that there may be some white on the outertail feather bases|
So what about the females? Well, to be honest they were probably Caspian Stonechats too, presumably armenicus, but you just can't do them in the field and this is coming from a man who likes to get his hands dirty with them - have a look here for some commentary and in hand shots from Israel. If what Yoav says holds true, then you can't exactly move the uppertail coverts aside in the field, but it doesn't seem like there is any white at the tail base on these Egyptian birds.
Also, I like Yoav's thoughts on what our 1st-winter birds could be in the autumn in Western Europe - perhaps categorising these 1cy birds into the maurus category is unsafe, plainly ignoring variegatus? So go and see a male Sibe Stonechat kidz. Just to play safe that your autumn Sdark-tailed Sibe unequivocally wasn't a Casp if you've only had autumn birds...