Yeah, I've thought about that a lot. And I think you could even find scripture for it. I mean, look at:
Psalm 19:1-2 - The heavens declare the glory of God; and the firmament sheweth his handywork. Day unto day uttereth speech, and night unto night sheweth knowledge.
Psalm 148 -  Praise ye the LORD. Praise ye the LORD from the heavens: praise him in the heights.
 Praise ye him, all his angels: praise ye him, all his hosts.
 Praise ye him, sun and moon: praise him, all ye stars of light.
 Praise him, ye heavens of heavens, and ye waters that be above the heavens.
 Let them praise the name of the LORD: for he commanded, and they were created.
 He hath also stablished them for ever and ever: he hath made a decree which shall not pass.
 Praise the LORD from the earth, ye dragons, and all deeps:
 Fire, and hail; snow, and vapour; stormy wind fulfilling his word:
 Mountains, and all hills; fruitful trees, and all cedars:
 Beasts, and all cattle; creeping things, and flying fowl:
 Kings of the earth, and all people; princes, and all judges of the earth:
 Both young men, and maidens; old men, and children:
 Let them praise the name of the LORD: for his name alone is excellent; his glory is above the earth and heaven.
 He also exalteth the horn of his people, the praise of all his saints; even of the children of Israel, a people near unto him. Praise ye the LORD.
Psalm 150:6 - Let every thing that hath breath praise the LORD. Praise ye the LORD.
Revelation 5:13 - And every creature which is in heaven, and on the earth, and under the earth, and such as are in the sea, and all that are in them, heard I saying, Blessing, and honour, and glory, and power, be unto him that sitteth upon the throne, and unto the Lamb for ever and ever.
Luke 19:40 - And he answered and said unto them, I tell you that, if these should hold their peace, the stones would immediately cry out.
Isaiah 55:12 - For ye shall go out with joy, and be led forth with peace: the mountains and the hills shall break forth before you into singing, and all the trees of the field shall clap their hands.
And I mean, if the rocks will sing out because mankind won't, I don't think it's too far-fetched to assume that the birds sing, too. I get the feeling that no matter how corrupted mankind is, nature will still turn to the Creator Who formed it. At least, that's what I'd like to think. And even if I can't find any proof for it, it's still a neat thought when I hear the birds singing outside my window, to think that maybe they're singing praises to God. He definitely deserves it!
He hath shewed thee, O man, what is good; and what doth the Lord require of thee, but to do justly, and to love mercy, and to walk humbly with thy God? -Micah 6:8 KJV
They have shewed thee, O teen, what is good; and what doth the world require of thee, but to fit in, be wealthy, have good looks, and be rebellious? -Peer Pressure 1:1
"I hate milk; it's like drinking vomit." -Edward Elric and me.
ClaecElric4God in regards to Wolfsong - You're the coolness scraped off the top of this morning's ice cream, after being pulled out of a beautiful summer day!