Statistics

I put in under the big bridge.  It's a nice day, a bit windy, but cool and mostly sunny.  Low tide has just passed, but it was not a particularly low low tide and even now I should be able to get through most of the marsh.  In any case, this is the time to get stuck in the mud as all one has to do is sit and wait for the water to rise.

I paddle down river and take a counter-clockwise route around the marsh.  There are quite a few Great Egrets, which gets me to thinking.  I spend most of the trip thinking about how ornithologists statistically account for the "spotability" of different birds.  

I have good enough vision and some people that paddle with me think that I am eagle-eyed.  But, what is really going on is that I am visually tuned in to spotting stuff in the outdoors - it's nothing more than practice and use of the senses.  I recognize certain shapes or telltale movements just because I've seen them so often.  One day, pointing out a far off Osprey to my mother in-law, she asked, "how do you know that that is an Osprey?"  I replied, "because that is what an Osprey looks like."

Back to Great Egrets, I figure that I can spot a Great Egret at about 600 yards.  They're bright white and mostly stand vertical - it's easy.  A Great Blue Heron, I probably spot those at about 300 yards.  But, there is a big difference.  If and Egret is standing still and in the open at less than, say 300 yards, I'm going to always spot it - always.  But, some Great Blue Herons, which are better camouflaged, aren't spotted until I'm 30 or 40 yards away.  The idea here, is that if you are out spotting birds, you are going to spot most of the Great Egrets, but a lower percentage of Great Blue Herons.  

Juvenile Night Heron

Then we get into the problem of hard to spot birds.  Egrets and Herons are pretty easy to spot if they are standing still, but some birds, like Willets and Sandpipers are much more difficult to spot unless they move.  A moving Willet is easy at nearly a hundred yards, but if it decides to stand I might get within 10 yards before it scares and gives itself away.  Then there's the Piping Plover.  Those little magicians with their feathers that match sand, shells and pebbles are invisible from ten feet away if they don't move - and they're not an easy spot when they run (which is one of the reason they are threatened - their nests get run over by beach walkers and loose dogs).  

Black Bellied Plover

And to make it more complicated, it occurred to me that if someone was counting birds from the Audubon Center near the marsh, their bird count of Night Herons just went up by a factor of five because of me because I flushed a lot more of them than were visible. The juvenile Night Herons were feeding in the lower corner of the marsh, as usual and they would have been unseen until they took flight.

Bad photo of a Harrier - but it is a photo of a Harrier

Anyway, I get to Milford Point, then head up Nell's channel where I get to watch a Harrier do its thing, take a diagonal back to the lower corner, and turn up the east edge of the marsh.  I find the secret passage the we found on our last trip in here - it is harder to find from this direction - just point the canoe into a minimal gap in the spartina and hope it's the right minimal gap.  I'm especially fond of "secret garden" passages - narrow little pointless dead end openings that actually open up into something big and grand.  This one opens up into a long diagonal route across the marsh that no one would suspect exists.