Albert Barnes Commentary Psalms 104:17

"Where the birds make their nests: As for the stork, the fir-trees are her house." — Psalms 104:17 (ASV)

Where the birds make their nests – This means furnishing a home for the birds where they may breed their young. In Psalms 104:12, the birds are introduced as singing among the foliage of trees and shrubs by the watercourses; here, they are introduced as having their home in the lofty cedars, in places which God had made for them.

The word translated “birds” here is the word which in Psalms 84:3 is translated “sparrow,” and which is commonly used to denote “small birds.” Compare Leviticus 14:4 (margin), Leviticus 14:5–7, and Leviticus 14:49-53. It is used, however, to denote birds of any kind. See Genesis 7:14; Psalms 8:8; Psalms 11:1; Psalms 148:10.

As for the stork – See the notes at Job 39:13.

The fir trees are her house – Her retreat; her abode. The stork here is used to represent the larger class of birds. The meaning is that they build their nests among the fir-trees or cypresses. See the notes at Isaiah 14:8; notes at Isaiah 41:19. So Milton says:

“The eagle and the stork
On cliffs and cedar-tops their eyries build.”

They build their nests, however, not only on fir and pine trees, but on houses and castles. Dr. Thomson (“Land and the Book,” vol. i. p. 504), says of them, “These singular birds do not breed in Syria, but pass over it to Asia Minor, and into Northwestern Europe, where they not only build in fir and pine trees upon the mountains, but also enter cities and villages, and make their nests on houses, castles, and minarets.”