If I were a Myrtle warbler (Eastern Yellow-rumped) I too would avoid your backyard because there seems
to be way too much competition for insects. Your yard appears to be a birding hotspot ... lucky you!
Obviously, insect biodiversity is impressive in your yard. Visitors in numbers are not there for the conversation,
they're there for the grub(s). Maybe Myrtle warblers prefer one kind of insect, something that tends to be present
in a marshy area where there is a body of water at least the dimensions of a pond. When I encounter Myrtle warblers
in the Rouge they are often close to the ground and within a narrow band along the pond's edge. I realize that what
I observe occurs close to where I'm stationed and if that happens to be close to the water then all the activity
I am witness to will be defined accordingly.
I have never seen a Myrtle in the yard, but then again, I rarely see a warbler at all visiting same. Should I notice a Magnolia in the cedars
then I can safely assume that Magnolia warblers are so thick and furious on that particular morning that I may flush them in numbers
on my way to the sidewalk, or that they may be waiting for the bus before I get there. I know of no unique biotome requirements for this species.
How long have you recorded warbler visitation in your yard? How extensive an archive are you basing your conclusions on?
I have no doubt that it is long enough to have raised the query in the first place.
Imagine that, two whole paragraphs and I've said nothing. Man, I'm on a roll. Any more questions?
Shortsighted (but long-winded).