By them the birds of the heavens have their home; They sing among the branches. (Psalms 104:12 NKJV)
Many birds do their singing to either claim their territory, their partner, or sing because of their new young babies. Many just sing because God put a song in their heart.
According to R. A. Torrey’s New Topical Textbook the above verse, birds “Have each their peculiar note or song.” Whereas Nave’s Topical Bible titles the verse as “Songs of, at the break of day.” Referring to a bird singing both refer to Psalms 104:12, Ecclesiastes 12:4 and Song of Solomon 2:12. Not only has God created the different birds, but has given them various voices even amongst their own kind. Warblers, of which there are many kinds, have distinct voices. I have to admit that I enjoy some bird songs much more than others, as you do also.
From the commentaries about Psalm 104:12, here are some of their thoughts:
Albert Barnes’ Notes – “Which sing among the branches – Margin, as in Hebrew, “give a voice.” Their voice is heard – their sweet music – in the foliage of the trees which grow on the margin of the streams and by the fountains. There is scarcely to be found a more beautiful poetic image than this.”
Geneva Bible Translation Notes – “There is no part of the world so barren where most evident signs of God’s blessing do not appear.”
John Gill’s Exposition – “By them shall the fowls of the heaven have their habitation,…. Another use of the springs, fountains, and rivers of water; by the sides and on the shores of these, some birds delight to be, and on trees that grow here do they build their nests; and here, having wetted their throats, they sit, and chirp, and sing: to doves, by rivers of water, is the allusion in Son_5:12.”
“Which sing among the branches; of trees that grow by the sides of fountains and rivers; see Eze_17:23. To such birds may saints be compared; being, like them, weak, defenceless, and timorous; liable to be taken in snares, and sometimes wonderfully delivered; as well as given to wanderings and strayings: and to fowls of the heaven, being heaven born souls, and partakers of the heavenly calling. These have their habitation by the fountain of Jacob, by the river of divine love, beside the still waters of the sanctuary; where they sing the songs of Zion, the songs of electing, redeeming, and calling grace.”
Matthew Henry – ” The birds. Some birds, by instinct, make their nests in the bushes near rivers (Psa_104:12): By the springs that run among the hills some of the fowls of heaven have their habitation, which sing among the branches. They sing, according to their capacity, to the honour of their Creator and benefactor, and their singing may shame our silence. Our heavenly Father feeds them (Mat_6:26), and therefore they are easy and cheerful, and take no thought for the morrow. The birds being made to fly above the earth (as we find, Gen_1:20), they make their nests on high, in the tops of trees (Psa_104:17); it should seem as if nature had an eye to this in planting the cedars of Lebanon, that they might be receptacles for the birds. Those that fly heavenward shall not want resting-places.
Oh, give thanks to the LORD! Call upon His name; Make known His deeds among the peoples! Sing to Him, sing psalms to Him; Talk of all His wondrous works! (1 Chronicles 16:8-9 NKJV)
Video of a Willow Warbler singing from a Hawthorn
Last but not least, we have a Song Sparrow singing by Tstormer on YouTube