For many years we have had several Western Tanagers nest and hang around our house and this is the first year we have not seen them. The Flycatchers have their nest in the usual place and when I go to get my tractor out I can see little heads just above the rim of the nest but no Western Tanagers this year at all. We have not seen the pine siskins, finches or juncos either this summer. The later birds all eat thistle and the association has a big thistle spraying project going on which is killing the native as well as invasive thistle. Remove the food source and the birds will move on to where there is more ample feed.
For as many years as I can recall we have had bat families roost in the bat box under the eve of our house situated high up. This is the first year we have not seen any bats. With all the agriculture hazards and old mine collapses the bats may be in peril too. In past years the bats have kept our mosquito population at almost zero. This year we have ample mosquitoes for many bats if they would only show up.
I believe the absence of certain species of birds and bats is not coincidence but I'm not sure what the cause is.