Ok, my understanding is that the Blackbirds start life as Feadogs. Does Feadog make an Eb whistle? Or is the Eb a Feadog D head on a Eb Generation body?
Not sure, Jerry can answer you on this one. Or if you haven’t heard in a while, you can PM him. He is on the boards here.
Eb Blackbirds use Generation Eb tubes. So it consumes two whistles to make one Eb Blackbird.
Best wishes,
Jerry
Jerry, what do you get when you put the leftover Gen head on the leftover Feadog tube? Given the desirability of the “Gen sound” and the in-tune construction of the Feadog tubes, I’d guess that might be an interesting Frankenwhistle.
I’m just doing a batch of those now. I sent one to MT Guru. Perhaps he’ll post comments.
Best wishes,
Jerry
Yep, I’m evaluating.
<Drums fingers on table, stares at ceiling, checks watch, repeats…>
Evaluating … Evaluating … BEEP! Evaluation complete. Please remove whistle, and return WhistleMark interface to the “Off” position.
It’s very interesting. Not quite a Generation, and not quite … something else. 
Basically, Jerry has tweaked the typical “skitter” out of the current Gen head and, at the same time, extended the breath range. The result is a whistle that keeps the basic Gen sound but is smoother, more stable, and easier to speak. The bell D and 2nd octave closed D are particularly solid, and these are often tricky notes on a Gen.
It also tolerates a much stronger breath than a stock Gen, and actually generates a surprising amount of both backpressure and volume. This makes it friendly for whistlers with less than perfect breath control, and expressive for experienced players who like to push the notes. The pitch is stable throughout the extended breath range.
Mating the head to the Feadóg tube* contributes equal temperament and added edge. The latter is important, because the tweak reduces some of the characteristic chirp and edge that many people like in a good Gen. The tube brings this back in a more subtle and controlled way, especially when emphasized with the breath. The whistle records particularly well, sounding both smooth and lively.
[* Substituting a Generation tube seems to result in a tamer, more subdued whistle with breath characteristics closer to a stock Gen and, of course, the semi-Just intonation of the Gen.]
As Jerry knows, as a vintage Generation fan I wasn’t quite sure what to make of this “GenDog” at first. It’s different from either the Blackbird or Mellow Dog. But the more I play it, the more I like it, and I think it would make a nice addition to his line-up.
Great, just what I need, another WhOA virus! So, Jerry, when will the GenDogs be available and at what price?