Sunday, March 18, 2012

How Far To the Curve of the Earth?

[Some of the 1000+ Northern Gannets visible (sort of) from shore along the Delaware Bay between North Cape May and Del Haven this morning. Most floated on the calm water, waiting for a breeze to aid flying. Who knows how many were on the whole bay in total? 10's of thousands seems reasonable, given that visibility until afternoon was under a mile. A reason to consider carefully before developing wind power facilities in the bay, however desirable those would be otherwise.]

A gannet thing did develop today, but it was a slow-burn sort of spectacle. Tom Reed texted me from St. Pete's, down in Cape May Point, at 9:04 a.m. saying he'd had 118 Northern Gannets in 5 minutes. When I checked Norbury's Landing a bit later, 10 or so miles north of Cape May on the bay, there were zero gannets in view, though visibility was barely a half mile. The sea and bay fog persisted all morning, but by about noon you could see a mile or a bit more - and what you'd have seen, were you scoping offshore in Delaware Bay, was a LOT of gannets, almost all sitting on the water. I suspect this was due to the wind, or lack thereof. Like a lot of seabirds, gannets utilize dynamic soaring to travel over the sea - and dynamic soaring requires wind. A scope scan of the bay just south of Cox Hall Creek yielded about 520 gannets, and another a few miles north at Miami Beach yielded another 530 or so.

Later in the afternoon, when the fog finally lifted and blue sky reigned, I returned to Miami Beach. A distant but huge flock of ~650 Northern Gannets was plunge-diving over an obviously big school of baitfish. They were so far offshore that the bottom of their dives disappeared below the horizon at the curve of the earth - which leads one to wonder, how far is that? Pretty damn far, 3 miles or more, depending on how tall you are, how high you're standing, how much refraction there is. . .let's just use 3 miles and let it go at that.

We could examine this horizon thing metaphorically. How far away the horizon is depends on where you are standing, and if you move, the horizon moves away, keeping pace with your advance. . . thus, we can never reach the horizon. But if you look straight up, there is no horizon.  There's none straight down, either . . .nor birds. Enough of that.

[Suddenly, there are Laughing Gulls in Cape May, a lot of them. Their cries fill the air, the sound of a seashore summer. But wait, it's only March. These were at Miami Beach in the Villas.]

 [Black-bellied Plover (left), Red Knots, and Dunlin (second from right) today at Miami Beach.]

Delaware Bay is famous for shorebirds in the spring, but go there at any season and you will realize how rich this system is. Amid the hundreds or thousands of Dunlin and many Black-bellied Plovers, I saw a color-flagged Red Knot on the Bay today (not one of those pictured above), with a green flag on the left leg and yellow on the right. Flocks of up to 80 or more knots have been on the bay this late winter/early spring, but one wonders where they are from - locals, Florida-wintering early movers, or . . .? Report any banded shorebirds to , which is where I reported the knot, though I could not read the alpha-numeric codes on its flags.

[6+ Pine Warblers were at Cox Hall Creek WMA tonight, including this male which foraged along the paved eastern-most path there.]

This evening while poking around Cox Hall Creek WMA with the dog, I couldn't help reflect how birdy that former golf course always is. Tonight it held Pine Warblers, a Red-headed Woodpecker, phoebes, yellow-rumpeds, Field and Chipping Sparrows, bluebirds. . .a good place.

 [The Cedar Waxwings at Cox Hall Creek WMA were flycatching over one of the ponds there, a feeding behavior they engage in routinely. Trout fishermen know this bird, or should - their activity over a stream signals a hatch of insects in progress. I'm not sure what's up with this bird's central tail feather, longer than the rest.]

[A bit of belly crawling resulted in a better shot of the male Dickcissel which continues at my feeders. I've been hearing this guy's distinctive brrrzt regularly since he first appeared last week, but seldom get a good look at him. I hope no truly rare bird ever shows up here - well, actually I hope one does, but the layout of my yard makes it unlikely that any birds would visit the feeders when more than a single cautious observer is watching, unless everyone is inside the house - which Daniel Boone, the Chessie, will not approve of.]

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