Many of us have sought caches during the winter. Iowa's weather brings us challenges, like the one I read recently for my cache Ode to Everybody Loves Ray, GC138QR. Its log is frozen. Or the opening is frozen. To seek and get a high from finding a cache to hitting a low because you can't open or sign the log does not bring enjoyment.
Because of that, my winters have been a time of nature study rather than cache hunting. Currently, the birding life list has been fun to add to. Without the leafy growth and with the confused migratory birds, my family has been able to see birds that we'd normally only hear. We're also trying to master bird photography. If they just held still, this would be easier!
We own many historic and a few contemporary bird field guides. I can't say I have a favorite, because each one is useful in its own way.