Thursday, July 28, 2011

Day 34: Migrants and salt marsh savant pay visit

Southbound shorebirds now dominate sky and marsh.

Like these 13 charadrius semipalmatus. That's more semipalmation than some birders can handle.

Rocky Point serves as a rest stop during their Canada - Caribbean migration. While the plovers relaxed, least sandpipers piped their hearts out. Yellowish legs distinguish them from their look-alike cousins the semipalmated and western sandpipers.

These minuscule birds (about the length of a chickadee) probed and piped everything, including hollow  phragmites stalks.

This one fancies itself a heron.

At times they piped each other.

But the day's most exciting visitor was the salt marsh matriarch herself, Dr. Judith S. Weis.

Judith and her husband Pete, also a biologist, have spent five decades investigating salt marshes, mangroves, estuaries, and man's impact upon them. She co-authored this book, an excellent primer, reference and historical narrative for all things salt marsh. It accompanied me throughout this entire cleanup project.

The book devotes a chapter to the myriad pollutants that end up in marshes, some of which lurk right under my nose at Rocky Point. Here, Pete points out the core of a large piece of castaway lumber. The green color indicates it's been treated with copper, chromium and arsenic (CCA). CCA wood is resistant to insect infestation and rot, which is why it's often used for outdoor applications. Copper, which causes the green tint, is extremely toxic to marine organisms as it leaches out. And a 12-foot 2x6 board of CCA-treated wood contains about an ounce of arsenic, enough to kill over 200 people. So don't throw green wood in your bonfire.

Judith was pleased with Rocky Point and recommended we continue our cleanup strategy of wood and debris removal. "Nature will take care of the rest," she added. She also remarked that she'd never seen a salt marsh quite like Rocky Point, due to the placement of the dunes and limited tidal exchange. Toward the end of the tour we were joined by NPS park interns and staff. Clockwise from upper left, Pete, Judith, Budhiono, Sarah, Jessica, Mary-Jo, Doug and Tony.
Thanks again to everyone for coming out.

Camera trapping was slow this past week. Here's the tally: mockingbird 1, robin 1, osprey 3 (over 2 days). I also caught USFWS biologist Brian in the act of cleaning up on his day off. It was exactly 95 degrees when this picture was taken.

An interesting Bushnell Trophy Cam flaw was illuminated as a result of Brian's efforts. Every time he entered from camera right, the camera would catch him dead center (above). But when he entered camera left, it wouldn't catch him until he already cleared 3/4 of the frame (below). By my rough approximation, the camera is around 40 feet from his line of approach.

Have any other Bushnell Trophy users experienced this issue? Leave a comment if so. Anyway, here's the best full-load shot I could salvage considering the limitations. Notice how Brian gets a running start to power his heavily laden wheelbarrow through the mud. Bravo.

Sarah and I cleared a section of middle marsh we call Willet Cove. This spot had served as a sort of willet headquarters during the past months. With any luck, spartina grass will colonize this bare patch next season, providing a safer and hopefully more successful nesting site.

High of 87, max humidity 90%, average wind NW @ 9 MPH, .7 low tide @ 11:38 AM. Moon 17% visible.
Water level recorded at 4 inch mark.
Birds seen in marsh: lesser yellowlegs, black skimmer, least tern, common tern, semipalmated plover, least sandpiper
Birds seen in bay: laughing gull, herring gull, common tern, black skimmer, least tern, semipalmated plover, willet, black-bellied plover

Thursday, July 21, 2011

Day 33: Nest-making, and a chase scene

Today the haze sat heavier than a 300-lb plumber on his lunch break. Relative humidity was six clicks shy of 100%. Vapor and smog combined forces to enshroud the Manhattan skyline for the first time in months. Yet the marsh life seemed invigorated by this weather, lining the channels to stab at the mud. Among them was this yellowlegs, a marsh first for me.

And this peep. In case you're not acquainted, peeps are a complex of five small sandpipers that look more like siblings than distinct species. Please leave a comment if you can ID this one. [update: it's a pectoral sandpiper in transitional plumage, ID courtesy Don Riepe]

The platform camera captured a green heron in a state of intense concentration on some mystery object. At this altitude, probably not a fiddler crab.

This sparrow also made a few appearances. Please leave a comment if you can ID. [update, it's not a sparrow at all... it's a female red-winged blackbird. ID courtesy Don Riepe]

The platform camera trap tally for the week ending 07/20/11 included: sparrow 5; red-winged blackbird 1; starling 3, green heron 1; osprey 6. The osprey pair visited 6 of 7 days, usually in the morning, spending an average 90 minutes each time. Though it's too late for them to lay any eggs, they have begun nest-building.

The building material appears to be largely composed of dried algae and phragmites. Here's their week's progress.

Guest marsher Jon Santos, having recently survived a nasty bout of whooping cough, dropped in to help clean up and fill his battle-weary lungs with marsh freshness.

Higher parts of the marsh were about as parched as I've seen them, thanks to the recent heat and low tides. The scattered, desiccated bodies of hermit crabs in the bay front channel attested to the harsh conditions. Aside from a few puddles, water was restricted to the main channel, and it wasn't pretty. But clean up is always easier when the debris and ground are dry. We managed to clear a respectable swath from the marsh middle.

As we raked, a large shadow suddenly sliced through the grass, drawing our gazes skyward to a massive female peregrine falcon towing a solitary least tern in hot, angry pursuit. "Brass balls," Santos muttered. Indeed. The tern appeared less than least, roughly the size of the falcon's tail feathers. It brazenly chased its would-be assassin around the marsh, coursing through the reeds and bashing into a tree before disappearing into the east. For want of a camera at that moment I offer this rendering.

High of 85, max humidity 94%, average wind () @ 4 MPH, 5.0 low tide @ 12:18 PM. Moon 79% visible.
Water level recorded at 4 inch mark.
Birds seen in marsh: great egret, yellowlegs, black skimmer, least tern, common tern, mockingbird, unidentified peep, peregrine falcon
Birds seen in bay: laughing gull, herring gull, common tern, black skimmer, least tern, semipalmated plover

Thursday, July 14, 2011

Day 32: (Almost) all work and no play

Our customary pre-cleanup marsh exploration yielded a dead adult Atlantic silverside, found in the bay front channel. This photo doesn't sufficiently illustrate the brilliance of it's 'silver-side', a blinding stripe of chrome so impossibly luminous I took the fish for a brand-new lure when I first saw it.

It might have been swept in with the recent high tides. But it was so fresh, I suspect it died after swimming into the marsh. Cause of death: a pencil eraser-sized hole near the ventral ridge, in front of the anal fin. A hit-and-miss by a piscivorous bird? That's one theory. But how did the bird manage to stab the underside of the fish? It looks more like a hole bored by a parasite. I'll be eager to hear any other theories.

Last week I spent most of the day shadowing the nekton monitoring crew. It was fascinating and a lot of fun, but it left me with the guilty feeling of marsh neglect. So today was a day of heavy labor. Sarah and I warmed up by first clearing the west channel. Each new moon tide seems to push in less and less debris, which is encouraging.

We then turned to the most challenging cleanup site, an area I'd been avoiding for the past nine months. The dreaded middle marsh. This area is perpetually muddy regardless of water level, never wheelbarrow friendly, and buried in wood and debris.

Trudge-force was the only option. We removed wood by the armload to the nearest dry point where we could bring the wheelbarrow. And we tackled the wet, heavy debris by pitchforking it into trash cans, and hauling it out one load at a time. Effective if not hi-tech.

While moving logs we disturbed a few little fiddlers. He might look like a monster but this guy was only an inch wide, buried in Sarah's glove.

The camera trap has finally found its Goldilocks position. Not too low, not too high, and with the added benefit of expanded marsh coverage. It now captures both what lands on the platform, and what lurks below. Clockwise from upper left: great blue heron (first record for marsh), green heron, mallard, Moshe.

As for the platform, starlings (5 visits), osprey (3), red-winged blackbird (1) and a willet (1) were recorded. Perhaps this willet returned one last time to lose itself in a moment of retrospective contemplation. How's that for anthropomorphisation, Tony?

The osprey visits lasted for 10, 80 and 40 minutes. One drawback of the current camera positioning is that I won't always be able to see what the osprey is eating. But maybe they'll humor me now and then.

High of 89, max humidity 49%, average wind NW @ 14 MPH, 0.1 low tide @ 12:57 PM. Moon 93% visible.
Water level recorded at 8 inch mark.
Fish recorded in marsh: adult Atlantic silverside (dead)
Birds seen in marsh: great egret, spotted sandpiper, black skimmer, least tern, common tern, cardinal
Birds seen in bay: laughing gull, herring gull, common tern, black skimmer, least tern

Friday, July 8, 2011

Day 31: Nekton monitoring

Upon arrival, I found the marsh teeming with.... scientists.

NPS coastal ecologist Patricia Rafferty had come to Rocky Point to train her crew in the use of throw traps to monitor marsh nekton, aka, swimming organisms. As Patricia explained, nekton are good indicators of  marsh health because unlike ground dwelling organisms, they can swim away if conditions aren't right. Throw trap surveys are employed before, during and after marsh restoration projects to track success.  Here's how it works. First, the trap location is selected, GPSed, and water temperature, salinity, and dissolved oxygen are recorded.

The three foot square trap is placed and any cover vegetation within the trap is identified. A rigid rectangular net is then swiped through.

Once the net is raised it's all hands on deck as the little fish flip about trying to escape. They're moved under the wet algae to keep moist (and still) until they can be tallied.

The fish are identified, counted, and the first 15 of each are species measured. This continues until three consecutive swipes come up empty.  It's precise and thorough work. The marsh is a nursery for juvenile fish, and at this size, it takes an expert eye to distinguish between species. From nose to tail, most are no longer than a pinky nail.

A horseshoe crab egg.

Atlantic silverside, Menidia menidia.

Striped killifish, Fundulus majalis

The crew found a number of sheepshead minnows, Cyprinodon variegatus, which Patricia noted are not commonly encountered in the nearby Jamaica Bay marsh islands.

The fish were all released back into the marsh. Check back soon for the results of the data the crew collected, which should shed light on how Rocky Point's fish population compares to that of other salt marshes.

Moving on to aerial organisms. The osprey pair visited twice, but my new mounting system was clearly not optimized for Nat Geo shots.

To make matters worse, some avian saboteur tilted the camera just four days into the camera trapping. Over 1,500 photos were subsequently captured of wind-blown twigs, 2x4s, and an ever-growing pile of bird excrement.

The culprit? A solitary fish scale stuck to camera gave it away. An osprey weighs only about three and a half pounds, but it apparently exerted enough force to dislodge one of the two screws holding the mount in place. Corrective measures have been taken.

Sadly, the marsh was bereft of willets today. Two pair had taken up residence since May. I saw breeding behavior on multiple occasions and a suspicious pile of downy gray feathers, but no chicks. Having failed to raise any young, the two pairs have likely moved on, although one lingered on the beach. The marsh feels empty without their incessant bleating and dive bombing. They will be missed. Here's wishing them a safe migration.

 In their place are the marauding skimmers. Not nearly as bold, but always a pleasure to watch.

I'll close with butterflies. Last weekend, biologist Steve Finn counted them at three Breezy Point locations: West Beach, Fort Tilden and Rocky Point marsh. Here's what he had to say about the marsh: "I used to include this area in the late 90's. I determined it was too difficult to access with all the accumulated flotsam (timber with nails, etc.). Now, not so bad." 
  1. Orange Sulfur- 3 (see photo below)
  2. Wood Satyr- 1 (Only specimen found in all three sites)
  3. Summer Azure- 1
  4. Clouded Sulfur- 1
  5. Northern Broken Dash- 3
  6. Cabbage White- 1
  7. Tiger Swallowtail- 1
  8. Common Buckeye- 3
  9. Eastern Tailed Blue- 1 
Impressive for a 15-minute survey.

butterfly photo courtesy Steve Finn

High of 92, max humidity 87%, average wind SW @ 8 MPH, 5.8 high tide @ 01:30 PM. Moon 34% visible.
*** marsh determined to flood at 5.9 inches.
Water level recorded at 7 inch mark.
Fish recorded in marsh: Mummichog, Fundulus heteroclitus; spotfin killifish, F. luciae; striped killifish, F. majalis; Atlantic silverside, Menidia menidia; sheepshead minnow, Cyprinodon variegatus
Birds seen in marsh: snowy egret, great egret, green heron, ? yellow and black warbler, black skimmer, least tern
Birds seen in bay: laughing gull, herring gull, willet, mallard, black duck, common tern, black skimmer, least tern

Sunday, July 3, 2011

Portmann captures the ardeids

Last month's supertide provided a great opportunity to observe a fascinating group of birds called ardeidae. This family includes the herons, egrets and bitterns, which range in size from the five-foot tall goliath heron to the pigeon-sized little bittern. At least ten species occur in our neck of the woods. Francois Portmann got some amazing shots of a black-crowned night heron, little egret and great egret. Check them out here. He captured this great egret right after it sniped a particularly large killifish from the marsh.

The great egret was active throughout the evening, as evidenced by Francois' amazing timelapse.

Photo and video courtesy Francois Portmann