I have a lovely ruby male who visits my feeder daily at 7am and 8pm for the past two years. I have also seen a smaller hummingbird who might be a female, but haven't been able to get a good look. I am pretty certain the male might be nesting in my pin oak in my front yard because I see him perching in the branches so regularly. However, I haven't been able to find a nest, most likely because the inner portion of the tree desperately needs to be trimmed and thinned.
I was planning on having an arborist (who is also a family friend) perform the tree service for me. I know he would be extremely careful in removing the branches if I told him there could potentially be a hummingbird nest, but I am concerned he (and any potential mate) would leave if I disturb the environment at all.
Does anyone know how "resilient" hummingbirds are to potential habitat disruptions? It would only take 2 - 3 hours to trim the tree, but I am sure there would be loud noisy chainsaws at some point. I enjoy sharing my morning coffee with him and would hate to see him go.
Male Ruby-throated are smaller than the female but it's often not noticed unless one has the ability to observe them side by side which doesn't happen very often. The male is never involved in nest building nor would a female even allow a male near a nest so the possibility of a nest in your Oak is probably not very high. If your tree work only involves trimming and not removal of the tree I wouldn't worry about the hummers too much since they will only be inconvienenced for a few hours and will in all likelyhood be back after the human intrusion has ceased. Where are you located? Joe M. Lakeland