Shorebirding on the Delaware Bay and an ID quiz of sorts

By Lukas Musher

On Tuesday I drove down to southern NJ to help David Mizrahi of NJ Audubon with his shorebird project that I worked on last year.  He didn't have me do any banding, bleeding, netting, or flagging.  Instead he had me go onto the beach and re-sight flagged Semipalmated Sandpipers.  The beaches are off limits this time of year due to shorebird migration, so I was very lucky to be able to get up and close with the birds themselves, and to get some phenomenal photographic opportunities.  

As I have talked about in the past, several species of shorebirds stage along Delaware Bay each Spring in coincidence with the spawning of the horseshoe crabs.  The fat-rich horseshoe crab eggs provide an invaluable calorie source for the migrating shorebirds, enabling them to finish their journey north to the breeding grounds in the high arctic.  

Fortescue is often one of the best places on the Delaware Bay shore to see the staging shorebirds, and that's where I was.  Above, you can see a few thousands shorebirds or several species (predominantly Semipalmated Sandpiper, Red Knot, Ruddy Turnstone, Sanderling, and Dunlin) roosting on the beach, and getting ready to begin feeding as the tide goes out.

Ruddy Turnstones are one of my favorite shorebirds, and what they lack in rareness, they make up for with charisma – or as Richard Crossley puts it, they are "the sausage dog of birds."

 Semipalmated Sandpipers greatly outnumber all other species, and yet they are one of the most severely declining shorebirds on Delaware Bay.  Red Knots are more famous, but in fact their numbers may be recovering, perhaps due to a strict moratorium on the harvesting of horseshoe crabs in the bay.  David Mizrahi has been studying this small and plain, albeit fascinating Calidris sandpiper for twenty years.  One of the biggest conservation concerns for this species has always been rampant hunting for food many countries throughout Latin America.

 I spent a lot of time scoping and sorting through the tens of thousands of birds looking for flags.  I found Red Knots from Argentina, Ruddy Turnstones and Sanderlings banded in previous years on Delaware Bay, and Semipalmated Sandpipers banded on the bay and two that were banded in Brazil.  I got tired of scoping, though, and took asylum behind the remnants of a disintegrating wooden fence covered in mold and algal residue.  It provided me with enough cover so that I could sit patiently as the shorebirds walked within ten feet of me allowing for fantastic photo ops.

A group of mostly Dunlin and Red Knot begin to take flight as I am noticed from behind the wooden remains.

A Semi banded on Delaware Bay!

One of several Red Knots I found that were flagged in Argentina!

Another D-bay Semi!

Exhausted by their long flights from South America and in preparation for the long flight to the arctic, Semipalmated Sandpipers recover and feed ferociously on the fatty crab eggs.

Incoming!  The Semipalmated Sandpiper landing on the right was flagged on Delaware bay by David's team.

Dunlin, Semi Sandpipers, and a Red Knot take flight, as the rest of the weary flock, including a couple of Short-billed Dowitchers, anxiously scamper forward.

Perhaps the most charismatic and infamous of North American shorebirds, a Red Knot in flight steals the frame from the other species taken to wing.

I may have spooked these Dunlin and Semis, but they know where they want to feed (AKA where the eggs are) and they come right back in to where they were before after two to three laps around the beach.

Finally, I leave you with a few photos of this bird.  I believe this to be a male Western Sandpiper, and upon consulting an expert, he agreed, though said he could not be 100% certain without photos of the underside.  I can tell you this, though, the bird was stockier and ever so slightly larger than the other Semis, and I remember thinking right away that it could be a Western based on build, rufous tones on the upper parts, and longer breast streaking than the typical Semi.  I welcome other opinions on this bird so feel free to post thoughts in the comments.  If it is a Western Sandpiper, this late date in NJ would make it very, very rare.  I will also be consulting more experts over the next few days, so maybe we can figure something out....most likely there won't be consensus.

Note rufous tones on scapulars, cheek, and cap, relatively long bill (though on the small side for Western, making it a likely male if confirmed), and blocky (not round like Semi) head.  I personally see some streaking making its way down the flanks, which Semi doesn't have.

He looks fat from this angle, more in favor of Western in my opinion.

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The Fortescue Feeding Frenzy

Red Knots, Dunlin, Sanderling, Semipalmated Sandpiper, Short-billed Dowitcher, Laughing Gull, etc.  See if you can pick out all these species.

Thursday and Friday this week we were woosh-netting and mist-netting at Fortescue Beach along the Delaware Bay Shore, a great spot to see the horseshoe crabs spawning and the shorebirds feeding on their fat-rich eggs.  One of the main parts of my job is taking blood from the shorebirds we catch.  The blood is then used to detect what the birds are feeding on.  Horseshoe crab eggs have a stable isotope signal that is different from that of other prey items (e.g. polychaete worms) and is detectable in the blood.  The birds at Fortescue are undoubtably feeding almost entirely on horseshoe crab eggs, and that is why we see thousands of birds there while the crabs spawn.  We had a good amount of luck there those two days, catching close to 200 birds total.  Here are some photos of the beautiful masses of shorebirds you can see there.

Red Knots, Dunlin, Sanderling, Short-billed Dowitcher, and Laughing Gull

More of the same

Dunlin and Semis (Semipalmated Sandpipers) coming in for a landing

Before the Levee Breaks...

By Luke Musher

As the weather continues to be poor for migration, birding continues to be relatively slow around Cape May county.  The wise bird-master and much revered veterinarian-in-training, Ryan Ford, came into town today to bird with me.  We started the morning off at Higbees Beach, expecting it to be slow, and had an okay morning anyway.  2 Ruby-throated Hummingbird, an American Redstart and an Indigo Bunting were first of years for us.  We also had a few Ruby-crowned Kinglet, Black-and-white Warbler, Great-crested Flycatcher and the ubiquitous Prairie Warblers were other good spring birds.  There were a number of White-throated Sparrows around as well, which, for whatever reason, was fairly surprising to me.

Prairie Warbler, Higbees Beach, Cape May, NJ

Prairie Warbler, Higbees Beach, Cape May, NJ

Indigo Bunting, Higbees Beach, Cape May, NJ

After Higbee we birded around Cape Island, but to be honest not too much of note was around.  We checked everywhere from Sunset Beach to Poverty Beach to Bunker Pond to the Beanery to the Meadows.  The only birds of note were a Prothonotary Warbler at the Beanery, Purple Sandpipers at the Canal jetty at Higbees beach, and the 3 Eurasian Collared-Doves at their usual spot.

Ryan told me that he has had trouble getting photos of Red-winged Blackbirds.  Of course he didn't take his camera out for the meadows so I took this one just to rub it in.

We then drove north through Wildwood, checking the coast guard ponds, Two-mile landing, and back bays, but turning up very little.  We made our way north to Nummy Island where a number of shorebirds were hanging out.  The only highlight here were about ten Whimbrel and a beautiful breeding plumage Red Knot in the few hundred other shorebirds that included Dunlin, Short-billed Dowitchers, and Black-bellied Plovers.  

Red Knot (middle) with other shorebirds, Nummy Island, NJ

Red Knot, Nummy Island, NJ

After that we head to Beaver Swamp to look at ibises - ibi? - with the hopes of pulling out a White-faced.  When we arrived somebody claimed to have seen one, and perhaps he did.  We looked for a LONG time, but most of the birds were far out and the heat distortion made it that much more difficult. Lots of Glossy Ibis, though, so definitely lots of potential.  I'll probably be back.  A Pine Warbler and singing Yellow-rumped Warbler were present in the patch of woods at the end of the trail.

Our last stop of the day was Heislerville.  I was glad to see that the water levels had dropped a little since the last time I was there, though they still seemed high.  Some shorebirds were present, though nothing of note - Greater and Lesser Yellowlegs, Semipalmated and Least Sandpipers, Dunlin, and Short-billed Dowitcher.  26 Black Skimmer were roosting on the middle island with the Herring, Ring-billed, Laughing, and Great Black-backed Gulls, and Forster's Terns.  Heading back out along the dirt road, we saw our FOY Orchard Oriole.


Tonight, as I'm now looking at the radar, I'm thinking tomorrow we should get a number of new birds as the flood gates open tonight.  I'm sure Drew Weber at Nemesis Bird will have a post on the night's migration in the AM.  Until then, happy birding folks and check out the radar right now!

Radar Right Now (~9PM) from NOAA website.