It's been a while since I've been able to do this, but I went for a walk during lunch last Wednesday (April 9th) and was surprised at all of the birds I heard and saw. Unfortunately I didn't bring a camera but I'll do my best to report on what I saw.
I came across several ducks, and interesting ones that included a Common Goldeneye pair (or so I think- male had a mostly white body and black head), as well as a pair I saw in which the male had white rings around its all-black neck. My Sibley Guide is really helpful since I encountered the ducks as they were taking flight, and it includes illustrations of ducks in flight. The Harlequin Duck has the same white rings I saw, but according to the description it's a coastal bird, so it's unlikely I would have seen it in an inlet of the Charles River. But currently, that's the best guess I can make.
I heard many red-winged blackbirds throughout my walk. At this part of the Charles River the banks are very close to one another so I was able to hear birds on the other side of the river as well. The first red-winged blackbirds I heard were on the other side, but on my loop back to the office there were some on my side also.
One of the surprising calls I heard was what I call a 'shrill beach bird.' It evokes memories of my grandparents' beach in Wings Neck, Pocasset (Cape Cod) since this bird was always there to keep me company on days I spent at the beach alone. This is actually at the top of my list to identify because I am so curious what it actually is after all these years. During one of my few trips to Monument Beach last year (local public beach where I grew up) I was able to spot the bird making these calls, but at the time didn't have my Sibley Guide and also didn't have a camera. If I remember correctly it was a rather nondescript bird that was very muted in color. I would say it was a very light brown, with no distinct features. I do have a disc with bird calls on it; however, so I'll try to spend some time today listening to it to see if I can eventually narrow it down. I know that once I hear it I'll immediately know it- it's more a matter of choosing the right birds whose calls to listen to.
Finally, I had a larger bird sighting that I have not been able to identify at all. This bird was roosting very high in a tree and did fly between the tops of adjacent trees but never came down low enough so I could see it. This would be where my much-needed binoculars would come in handy! It was also a sunny day so it was difficult to look up for that long. The most distinguishing feature I could see was that it had a slight crest on its head. Its overall color was light brown/taupe and it had a distinct call. It was large as I mentioned, at least 10" long. My initial thought was that it was some type of Flycatcher, but I'm having trouble matching it up with any of those.
I suppose one way to solve some of these difficult identifications is to make a return trip this week!