Your "black diamonds" may be grackles
. A grackle looks like a little crow with yellow eyes. Bigger [11-17"] than a Robin [at 10"].
Your "Four-O-Clock-in-the-morning" bird could be the Song Sparrow. Song sparrows have a dark spot in the center of its breast. (Morning light starts at 3:30AM nowadays -- time for a male song sparrow to sing for a mate).
It's song has been described as "Madge-Madge-Madge, put on your kettle-ettle-ettle".
Behavior ("dives on Crows, searches shoreline for food, catches fish"), size ("Robin-sized, Crow-sized") and song (trills, twitter, whistle, warble) are very helpful in identification
. Color is less helpful for brown birds -- there are many phases of "browns". Patterning is good (streaked, spotted, stripe through eye).
Start the morning with a Robin -- the
least musical member of the gifted Thrush family: "Cheer-up—Cheerily—Cheerio-Cheer-up". (A cheerier way to start a day at The Lake.)