In northern Illinois, like other places in the Midwest, we are experiencing some unseasonably warm temperatures.
Daffodils at my parent's yard
Recently I went hiking at Lake Shabbona State Recreational Area in DeKalb County, Illinois and it was 80 degrees. The average high temperature is lower than what the recorded low was.
It felt so much like summer yet it "officially" wasn't even Spring (this was on March 18th).
But despite quite a few early recorded dates of some species in the area, the bird diversity seemed fairly "normal".
The duck numbers on the large lake were good and diverse, yet mostly at the extremes of scope range. The warm temps brought out fishing boats en masse, forcing much of the waterfowl to the far end of the lake.
I managed to find a handful of Horned Grebes, one of which I digiscoped (poorly).
Among the ducks were scaup, Canvasback, Northern Shoveler, Ruddy Duck, Red-breasted Merganser, along with a fair number of coots.
I was surprised by the lack of sparrows, not hearing any White-throated, White-crowned, or Fox Sparrows. There were plenty of Song Sparrows but it seems with the warmer weather, the other sparrows would be coming out.
I've found Tree Swallows and Eastern Phoebes already this season which definitely feels early.
Of course, this isn't scientific and just my casual observations. I personally believe that the warm weather and early feelings of summer are not having an adverse effect on the birds.
I do wonder what will happen if we get a sudden change of weather and it drops down below freezing. Our last frost date is around May 13th so it is likely we will be 50 degrees colder at some point in the next month and a half.
Regardless, I will continue to enjoy the warm weather and observe how nature reacts to it.