This songfest is for Will Post, Nathan Dias, and Aaron Given. Will, an expert on the species, told me long ago that, despite wintering in our local Spartina marshes, Seaside Sparrows don't nest there. They retire to high marsh, where the likelihood of a nest-destroying high tide is lower. (No one told the Marsh Wrens this trick.) I told Will I had recorded this unexpected behavior, but I never got around to sharing it with him. So here it is. Nate and Aaron both told me about good places to record singing Seaside Sparrows, in Needle Rush (Juncus) marshes = "high marsh." Thanks to all, as recording Seaside Sparrows singing from Juncus stems has become one of my favorite pastimes.
Before this event I had not heard the Seaside Sparrow sing, so I thought at first I was hearing blackbirds in the distance. Blackbirds do sing in close quarters like this (15 inches apart per my dictated notes), and Seaside Sparrow voices resemble those of blackbirds. Compare the Tricolored Blackbirds on April 4. This cacophony rather resembles that one. Scroll down to see the sonogram below for a manageable number of sounds, coming from at least three males singing on territory. The first good one is at 12 seconds in.
There must be something about nesting in marshes that has led both to converge on these harsh tones; as well as warming up for the breeding season by singing in groups. Write me if you know more: web at archmccallum.com.