Last summer I was hiking through a grove of Cedar trees and I noticed that there were Black-throated Green Warblers there. And then this summer while looking at Cedar trees, I found the Black-throated Green Warblers again. The bird guides talk about BT Greens inhabiting mixed coniferous woods, and while that is true, they seem to really like Cedars.
You can walk among the Cedars in some places and their large size has shaded the ground so much that there isn’t any underbrush. You can walk about with ease – there’s not much for dead fall either. In the quiet of the Cedar woods the buzzy sound of the Black-throated Green Warbler comes through loud and clear as they sing their zee-zee-zee-zoo-zee song.
The native Northern White Cedars, Thuja occidentalis, in our area are pretty special trees. I’ve heard that the groves of mature Cedar trees got started early in the 20th century and their start involved a very specialized climate. It was cool and wet. Since that time, that particular climate has not been duplicated and the sprouting and growth of new Cedar trees has been hampered by this.
In the U.S., the Black-throated Green Warbler is more common the further east you go. Here in Minnesota, we are at the western edge of their range. Some people from out west travel to Minnesota to add these Warblers to their life lists. Their Latin name is Dendroica (meaning “tree-dweller”) virens (meaning “growing green”).
Like several other warbler species, Black-throated Green Warblers sing two different songs. The second one would be called their alternate song. The two songs of Black-throated Greens are easy to learn, once you identify the bird. Ornithologists refer to them as the accented–”see, see, see, su-zee”–and unaccented–”zoo, zee, zoo, zoo, zee.” The pnemonic phrase for the unaccented song is “trees, trees, murm’ring trees”. The first song phrase is sung mostly by males when females are around. The unaccented “trees” song is sung while defending territory from other males. This is one of the Warblers that keeps their distinctive plumage through out the year; they don’t molt into a non-descript plumage after the breeding season like many of the other Warblers.