Calling all you Overton/Goldie Big Hole Low D owners out there . . . how do you do finger vibrato on your whistles. I learned finger vibrato as a repeated tapping motion on open holes leaving one or more holes open below the note but find with this whistle that on any hole this technique produces an exaggerated effect . . . probably because of the size of the holes. Davy Spillane appears to waggle one or more fingers over open holes without touching them but I can’t figure out which open hole(s) for which note. I would welcome feeback on what your big hole players do . . . or on what Davy does.
Ah, the whistle whammy bar! The finger vibrato effect can vary from whistle to whistle but it’s basically the same technique on any whistle no matter the size of the holes. Still, a big BH2 hole can be a plus though, IMO. That seems to smooth things out a bit.
Tapping isn’t a description I would use. Tapping a hole usually means that the finger hits the whistle and momentarily may close the hole. A tap is a different articulation ornament.
In my experience with finger vibrato you do not want to actually close any holes but merely disrupt the venting of the open holes - basically moving the fingers up and down above the holes varying the speed of the movement faster or slower changing the pitch of the note as the feel of the music dictates. It can help if you are a nervous type on stage sometimes. 
Some teachers will instruct that you leave the hole for the note being played open. Others might actually use that first open hole and judge the success of the effect by the way it sounds. When you think about it, that’s the only way you’ll get finger vibrato on the first octave (or second) E note - and that works fine with practice.
I’d suggest that you go zen and just listen to your long notes, eventually the vibrato will sound great without having to worry about what technique you are using for each note. Just wiggle the fingers that aren’t holding anything down - but from the heart. In other words, you’ll get a good finger vibrato if you use your ears to play it.
Feadoggie
Sorry, I wasn’t using the word tap in connection with the ornament which I’m fully aware of . . . but just as the action. Coincidentally however, two professional players of note have taught me just that technique for vibrato . . . of opening and closing the holes albeit swiftly. Hence the need to alter that technique for a whistle with such big holes.
Feadoggie’s onto it. I first learned it by tapping very close to but not actually over the hole. Kind of like shading the hole a little. It varies by the note you’re trying to “vibrato-ize” 
as to how much of the hole you need to shade. In some cases none. You will also note that it is difficult to just wave your finger above the hole in the beginning so this technique, for me at least, helped with that transition.
It is also true, and some ITM players will chastise you for it, that your natural vibrato, like when singing, will come into play. Then you are well on your way to the infamous “glottal stop”. Some players will tell you that this is forbidden and all vibrato should come from fingers only. Can of Worms alert!!!
ecohawk
I’m not surprised by the different manners that some players use to get their vibrato. It’s one of those play from the soul things. The effect can be very much over-the-top if you actually close the holes though - not unlike a divebombing vibrato on guitar I guess. It all depends on what you want things to sound like.
I like Spillane’s touch. He plays with more soul than many players.
Who are the “professional players of note” that teach closing the holes for vibrato? Just curious. I used to go to a lot of workshops and never heard that taught. Sounds a bit more like “tpping” (a fluting technique) than finger vibrato. I can recall a couple of spirited discussions on the topic though and some very humorous ones as well.
The big holes don’t really require a different technique, MtB. The end effect of the same movement from a smaller holed whistle to a larger holed whistle will be different though. The larger holed whistle (and keep in mind not all the holes as as large as others) will not vary the pitch as widely as the smaller holed whistle, IME, because of more generous venting. So the smaller holed whistle may require a more delicate touch to create a nice vibrato. The larger holed whistle may require a more exaggerated motion to get the quivering pitch or at least the finger action might need to be closer to the hole than on a smaller holed whistle. Again, either design works and it’s a matter of familiarity with your instrument that matters.
Large holes are not really necessary on a low D whistle from a pitch production perspective - at least that’s the physics in theory. But I do think it is more than a matter of fashion in the case of working the finger vibrato.
Hello, ecohawk. Second can of worms this week! Mind you I’m not taking sides on any of this. As I said earlier, it does not matter as much how you do it but how you sound.
Feadoggie
Not to oversimplify … but to oversimplify … 
Fully or partly close a vent hole or some combination of vent holes below the sounding note. Wiggle your fingers until you get the sound you want. Really, it’s that simple. Don’t overthink it.
For a shallower vibrato, occlude less of the hole(s), or use lower holes.
Feadoggie, I fully cover the holes all the time. But I’m not a pro. 
Thanks for the feedback. I think it’s down to experimenting and see what’s best. I do like Davy’s sound and he clearly waggle’s his fingers above the holes but which fingers and holes for which notes I don’t know. I’ll have to watch videos of him again slowed down. It would interesting to know since his was a big hole Overton.
That is quite an oversimplification, because it’s only one of the four different ways I regularly do vibrato on Low D whistles.
Because describing them is difficult, I made a video demonstrating them
Richard, the topic of this thread is Finger Vibrato. The second two techniques in your video are not finger vibrato, and don’t apply.
Of the first two techniques, your first demonstrates fully closing holes, and your second demonstrates partly closing (i.e. shading, occluding) holes. What part of that differs from what I wrote above?
I like that advice.
Well, I don’t claim pro status nowadays either. It’s an over-rated moniker anyway.
It’s just nice to hear how other players approach this. As I said I don’t think about technique a lot.
I went out into the garden for awhile today with a low D and just played. And I can see how closing holes would work. But I guess I prefer to shade holes from the side myself. And I do shade the first open hole much of the time too.
I think any technique works if you use your ears.
Feadoggie
and on my video I also demonstrate partly closing (“shading”) the actual hole that the note is emitting from, and partly closing (“shading”) a combination of holes including the actual hole the note is emitting from (as distinct from limiting oneself to holes below).
I consider “shading” and the sort of vibrato made by fully closing a hole below (in some cases involving dedicated “false” fingerings) to be quite distinct, due to their quite different sounds.
In addition are two types of vibrato (diaphragm and throat) admittedly not mentioned in the thread title, but which might naturally enter a conversation about Low Whistle vibrato.
I’ve just watched the Riverdance video’s (the opening solo and his opening solo to Lift the Wings) at ultra slow speed to try and analyse Spillane’s technique and it seem to involve far less “hovering” that I thought and perhaps more contact with the whistle. For E, he does to appear to hover his fingers over the edge of the B3 hole; I say fingers because for this he links his ring and little fingers together as one unit presumably to gain more control and stability. As far as I can see with the other holes he leaves an open hole and taps the edge of the hole below it. High D he taps T1 and for C natural he taps B2, maybe full-on and not the edge. Maybe others would care to look and comment.