There is a picturesque shaded, mossy path on the north (or northeast) side of the property that leads to a wooden dock jutting out into Weesuck Creek. Almost every day this dock is littered with crab shells (Blue Claw and Spider Crabs) and shell shells (mostly Ribbed Mussels with an occasional Quahog Clam). We also have mussel shells scattered on the marsh grasses and on our 'front lawn', sometimes quite close to the house. Dopped by gulls? Somebody is catching these delicacies, carrying them to the dock (or wherever) and cracking them open to get at the delicious meat inside (Ribbed Mussels are, in spite of what many books say, quite edible; we used to eat them all the time in cookouts). But who are the artful, if messy diners? For a long time, I thought it was the gulls who hang out on on local docks and shores and whose powerful beaks are certainly strong enough to open shellfish and crustaceans. But more recently I have also noticed blobs of mud on the dock and some fairly neat looking pellets. Owls are famous for extruding pellets and hawks sometimes do the same. But raptor pellets are full of the undigested bones and these pellets appears to be made mostly out of grass and seeds. Mud and pellets made of grass and seeds? The culprits -- in most, if not all, these cases -- must be raccoons.
Several people have pointed out to me that the early morning Purple Martin vocalizing that I wrote up a few days ago is the famous Purple Martin 'dawn song' meant to alert other Purple Martins -- scouts as they are usually called -- to the presence of the colony and lure them in to join. This is the song that is played in recorded form on loudspeakers by Purple Martin enthusiasts when they try to set up a colony; indeed, it was used to help set up this very colony a few years ago. It fooled me at the time into thinking there were real Purple Martins there and clearly it fooled the Purple Martins as well since they arrived shortly and have been there ever since. All this makes sense except that the dawn song has been sounding over the house (a good distance from the colony) and in the middle of June (when there are surely very few Purple Martin scouts around looking for a good spot to settle down). The probable answer is that the song -- and I do regard it as a song -- is given in the air on a wide circular flight, thus advertising the whole area (and not just the actual housing site) as martin territory. Most references to the Purple Martin dawn song state that it occurs during nest building and that its primary purpose is to attract other Purple Martins to the colony. But is this true? It certainly attracts other martins (females perhaps?) but I have yet to find any authoritative scientific study on this. I went looking in the two recent books of Donald Kroodsma (the best general books I know on birdsong) but without finding anything. I suspect that, like other bird songs, the dawnsong will turn out to belong to a male or males advertising themselves and their territory in the classic song bird style although perhaps in a slightly unusual context. But how exactly does it work? Do the males take turns? Or is there a lead alpha male who does all the singing? Does being the vocal lead (the Tony Martin or Dean Martin of the colony) mean he's the one who gets the girls? Fathers the children -- or most of them? Purple Martins are not exactly obscure birds; somewhere there must be studies that illuminate their musical, social and sexual habits!
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