It seems like winter is almost in full swing in some places in the USA. We have already experienced our first snow storm and thick ice on the roads and yet migratory birds are only just starting to fly south.
I live on the west coast of the USA and I witness the annual Pacific coast fly by of migratory birds each year. As the weather has becoming more temperate in the Pacific Northwest, more and more birds are choosing not to fly south for the winter as much as they use to do. Canadian Geese can be spotted in vacant wintering fields most of the winter, they are not migrating as far south as they use to. Using a spotting scope you can see other migratory birds wintering in the Pacific Northwest and not in California or Mexico like they use to.
Hummingbirds about the only birds that are still making that long trek down to south America each year but I wonder if California is seeing them the year round now. It looks like we should be watching our fine feathered friends closer if we wish to see how our weather patterns are doing.