I was reminded again yesterday of the changes that have occured over the past few decades. When I was in college, not all that long ago, I could keep the windows open and enjoy spring air until about the middle of April when the medley of tree pollens finally became too strong. The oaks traditionally joined in about the end of the month, just as the warbler migration revved up and shortly before finals. This year, as is the new normal, some Maples started flowering in early March and the first oaks I saw in flower were at the beginning of this week, with oaks in flower everywhere as of yesterday. We shut the house and turned on the air conditioning anyway because of the 80-90 degree temps this week (which at least have caused the global warming deniers to go into suspended animation until the next cold spell wakes them up), but that helps with the sneezing and weeping at night. By my estimate, that makes about a 3-week shift earlier in only 30 years. The warblers have shifted a bit as well, but not that much. I have no idea whether that has been much of a factor in the decline of warbler numbers now, compared with what I used to get 30 years ago, but I have to think it hasn’t helped.