[Too lazy and tired to read this over properly/obsessively before submitting like I normally would, so caveat emptor. There may be horrendous typos, incorrect usage of the words "to" and "too", grammar mistakes, random non sequiturs taking place midsentence, et cetera. Just be happy you're getting a disclaimer, I don't even usually bother with that, but as I've written so much already...] 

Well, it is, as you mentioned, small. So! One pretentious overanalyzation coming right up!

"Bale lifted up his broad head and howled," I like this as an opening statement, it's simple and to the point, cleanly descriptive, active voice, all that jazz. 

"his melodious voice filling the large canyon beyond him." Melodious voice? Howling is generally not the sort of thing I would label melodious, personally, so the choice of adjectives here seems a bit off. Of course, that's a matter of stylistic choice. If Bale really does have a melodious voice, he has a melodious voice, and that's that. Still. Something to consider. (Maybe powerful? strong? exultant?)

Also: the canyon beyond him? So is he in the canyon? Or at an "entrance" to the canyon, where the ledges aren't terribly noticeable, but get much higher very quickly from the point where Bale is sitting? The latter seems more likely given the usage of "beyond," but the former fits better with the concept of his voice "filling" the canyon. Consider deleting "beyond him" entirely, maybe replace "the canyon" with "his canyon" if you want to emphasize the wolves=territorial archetype. But, anyway, "filling the large canyon" works and you avoid the issue of confusion created by the ambiguousness of the word "beyond." Perhaps you could make this its own sentence instead of tacking it on to the previous one (e.g. "His melodious voice filled the large canyon" or "His exultant voice echoed in the canyon" or something.).

"The shady crescent of a moon vaguely illuminated the winterland about him," You're getting a wee bit purple prose-y here, erring to the unnecessarily wordy. To quote Stephen Sondheim*, "Less is more" and "God is in the details" and "Content dictates form"** And to paraphrase a bit more, you should aim for simplicity and clarity when you write, rather than striving to prove your intelligence and technical capability. On the flip side, you want simplicity without being simple.*** 

In other words, you don't need to say "the shady crescent of a moon vaguely illuminated the winterland" to make your point, namely that the moon is new and not very bright and also it's snowy, and that if you rephrase it more succinctly without saying "the moon is new and not very bright and also it's snowy" or some variation thereof, you will make that point even better. "The pale gleam of a crescent moon barely lit the surrounding winterland"  or "the snowdrifts gleamed dully in the weak moonlight" or something. 

"about" in this context is an unusual, possibly slightly archaic usage which the reader will most likely read as "around" anyway, so consider either replacing it with "surrounding him" or similar, or even just deleting it entirely. Or rephrase the entire sentence, should you feel the need to in light of my above ramblings. [Which you definitely should not feel obligated to do. EVER. By anyone, unless you're writing an essay and your teacher tells you to, or if you're writing a book for realsies and your editor wants you to make changes, in which case you should carefully consider before doing so, unless it's like a grammatical thing. This is your story, I don't want to write it for you.]

"and his grey-cream colored pelt" there shouldn't be a comma before "and" because this isn't an independent clause. [This is the exception to the above bracketed rant, 'cause it's a grammatical error and you should fix it.] So, if you don't change the previous bit at all, it would read "The shady crescent of a moon vaguely illuminated the winterland about him and his grey-cream colored pelt."†

"grey-cream colored" seems odd to me, because grey tends to be a colder color and cream is more warm, which means they don't mix well, so unless you meant that Bale's coat was mottled or otherwise two-toned (in which case, you should consider stating that explicitly, i.e. "mottled grey and cream coat"), then I'd reccomend you choose either grey or cream for the sake of narrative simplicity. 

"The reason for his triumphant howl was this: his mate had [had, given birth to, birthed, etc., you need another verb here] her first litter of pups." The colon makes it seem overly formal and far more clinical than it ought to be for a celebration of new life, so you might want to consider rephrasing it. Also, "had" in this sentence is an auxilary verb helping to form a pluperfect tense, so you need another verb after it, e.g. "she had borne her first..." or "she had given birth to her first" or "she had had," though I don't reccommend the last one for reasons that should be obvious. 

On the whole I quite like it, and my eleven year old self is reflexively jealous of your eleven year old self's writing skillz. I was still mostly on the "See Spot run"/cliche ridden/strictly passive voice train at that point.

--- 

*Oh yes, I went there. I did warn you this would be a pretentious overanalyzation, did I not? 

**Those are his three golden rules of writing. See: Finishing the Hat. 

***And I will stop talking about Sondheim now. Promise. 

†If you do choose rewrite the preceding sentence entirely, consider something like "Weak moonlight cast deep shadows in the snow and tinted his creamy pelt silver" or similar. Just remember that if the second part of the sentence (i.e. the reference to Bale's coat) is not an independent clause you do not need a comma.

@TNO: I can always tell when it's your writing and not someone else's. Even the disclaimer positively screamed TNO. :)

This is definitely a good start for a story! It's well-written and descriptive, almost poetical, and there's a little suspense too. The only things I would change are:

1) The second sentence. I personally like "The shady crescent of a moon", but the words "illuminated", "winterland", and "about" just seem a little too stuffy and out of place.

2) "Gray-cream colored pelt". It's not that the color doesn't make any sense, it's just that the wording is a little awkward. You could say "creamy gray pelt", or you could just say "cream" or "gray".

Other than that, great beginning! Please post more if you have the time!