Man I loved this piece, a lot of great things to talk about.
First of all, tone poem complete haha. Your piece was very true and idiomatic to the context your were going for. The strings especially created the sensations of waves and winds. Have you heard the piece "The Swan of Tuonela" by Sibelius? Some of the oboe and clarinet lines reminded me of the longing melodies he uses, awesome job at creating a picturesque world!
I also really enjoyed the sustained dynamics in the strings, great use of an instrument that can sustain forever while still keeping those lines interesting by swelling their volume. It's a nice pulse effect! The harmonics in the strings after what I can only assume was the section where our bird friend meets it's demise was really cool too. In general, what I'm getting at is you use the orchestra brilliantly to create a sparse and unsettling atmosphere.
However, I think it would benefit you to thicken the orchestra as well in some spots. For instance, you have hits in the strings before the harmonics section I mentioned that use this chord:
F# C# G B F C F# B
What a cool chord to use in this moment, and it's fine as it stands. But the tuba's play the Bb (A#?) and the bassoons play B nat? It's a cool percussive effect, but I think you would get a much stronger root of the chord if they were all doubling the F# (or whatever the root of your chord is :D), and then you have all of the dissonance you want with the minor 9ths and split 5ths you desire.
Also you mention your our own musical voice. I think that's what we are all striving for, and you have definitely developed your own unique personal style. What I would suggest is that you make that a bit more clear in your writing. I guess it just depends on what you're going for. If your plan is to have an orchestra perform this, your score looks incredibly clean and tidy. You don't need any help there! I didn't care for the giant time signature changes (no worries, just a style preference), but as I read on it grew on me. I'm more concerned with the enharmonics. The cello at one point was reading F# for a while, and then all of a sudden switched to Gb. It's just harder to follow along with, but honestly I know that most of us here aren't getting these wonderful orchestral ideas performed and we have to rely on sound samples, but for the future I would kind of map out the language and tendencies of accidentals to keep it more consistent in how you're thinking about your piece, and then if you have to import into Sibelius or Finale or whatever you use, it's much more clear to you how you want the enharmonics to appear.
The only other thing I would watch out for is the breathing in the winds. There are several long legato passages where I would be worried about the steady stream of eighth notes, but to be fair I'm not a wind player so I would always ask their opinions on any lines I'm unsure of. More importantly, Mozart said it best when he mentioned how rests are more important then the notes themselves. I know you were going for an atonal approach, but something as simple as removing a few eighths out of a set of 16 or so will a lot of times give an easy way to create syncopation and more phrasing to the great lines you've given.
Overall, any qualms are small for me and you absolutely achieved a wonderful tone poem that had me captivated from the beginning.
Thanks for sharing!