Preliminary and anecdotal report on GCA’s work for 2009 at Delaware Bay… shorebird research and bird photos

by Lanny McDowell on June 6, 2009

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Our Pennsylvania-based associate John Patrick Brown arranged a just-in-time house rental which offered us the option of either staying in a nice old farmhouse once owned by Lucky Luciano or using the current owners’ beach house right on Delaware Bay at a place called Highs Beach, which is just south from Cook’s and Reeds beaches, both well known as annual shorebird feeding and resting sites situated up the bay coast from Cape May.

The permits for Global Conservation Alliance (GCA)  to conduct research this year specified Cook’s, Reeds, Moore’s and Gandy’s beaches as locations for our work.  The procedure to collect Horseshoe crab eggs involved sampling certain marked plots according to  protocols developed by Norm Famous, who has the credentials and background to do that sort of thing.  Three of the four beaches were associated with the outlets of estuary systems draining out of extensive marshlands emptying into Delaware Bay from the New Jersey side.  Two of the beaches were long uninterrupted stretches of sand.  Two contained a variety of bayshore surfaces and substrata, including clay and silt layers, sections of peat and areas of mixed sand and pebbles washed by strong tidal currents.

Our objective was to identify places on the beach that horseshoe crabs would prefer for egg nests and to dig “soil” samples of a given size, record their locations and measure the density of crab eggs found in the samples stored in zip-locked bags.  After collection on the beaches, the samples were transported to the beach house rental where three GCA members and associates washed, sifted and rebagged each sample, then counted the number of eggs in each labeled bag, then tallied the egg counts for later comparison.  This sampling protocol was chiefly designed to show how the number of eggs contained in an undisturbed sample of beach area would differ from a sample collected after the beach had been disturbed by raking up the sand from as deep as nine inches and from as shallow as four to six inches.   Each set of plots contained a control plot.  Our forthcoming experiment results will be prepared by Norm Famous as a requirement of the permit issued by New Jersey Department of Fish and Wildlife, so I will not elaborate further here.

A second experiment had to do with distributing Aquamax, the manufactured food we tried out in 2008 as a possible substitute for horseshoe crab eggs.  This experiment was chiefly a matter of observing the reaction of both shorebird and gull species to food alternatives and to the areas of beach that were disturbed (raked up) in the course of our egg sampling process.

Porter Turnbull and I had arrived in New Jersey on the 26th of May, when we were joined by John Patrick Brown, who assisted us last year.  Norm Famous and Pete Gilmore, who is new to the team in 2009, arrived late on the 28th.  Teams worked on the beaches everyday at one location or another, with the exception of May 30th, which was devoted mostly to egg processing and counting after one sampling set was taken in the morning.  The beaches were sampled in this order:  Moore’s, Gandy’s, Reeds.  Cook’s Beach was used exclusively for observation, whereas the other three provided egg density samples as well as opportunities for observation.  What we found during our late May stay this year was quite different from the scene we experienced last year.  In 2008 most Red Knots and Dunlin were concentrated at Moore’s Beach, feeding shoulder to shoulder at the mouth of the estuary; and spawning crabs were not that easy to find.  This year that location was dominated by Laughing Gulls and crabs were in abundance.  Feeding and resting flocks of shorebirds could turn up anywhere along the main beaches this time, working the water’s edge or gathering at the inside corners along the beach where an eddy or a jetty concentrated the horseshoe crab eggs.

Last year it was hard to even find eggs on the surface of the beach.  In 2009 you could see in some places at certain tides an endless profusion of the small greenish eggs littering the wrack line:

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Moore’s beach scene, LAGUs and crabs:

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Fearless adventurer amongst the beasties:

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Porter hand raking one of our test plots with John labelling samples in the background at Gandy’s Beach:

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Resampling after the receding tide:

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Typically we would dig out samples and rake the plots to obtain more samples starting at a low or rising tide.  Then we would watch the feeding activities of shorebirds working the advancing edge of the rising tide.  In some cases we resampled our plots, which we had marked with poles in the four corners, to measure egg densities after the passage of the high tide and the predation of the feeding birds.

Overall, I would characterize the work as tedious and the data as useful.  The human company was well matched and the locations inspiring; and the birds as always were a miracle.

We were told fairly early on that the major northward departures of Red Knots occured on the 26th, our arrival date.  However, both the weather and the numbers of shorebirds in our vicinity, and Red Knot numbers in particular, all improved daily, right up until our own departures on June 1st.  We witnessed the largest aggregations of birds at Cook’s Beach on May 31st, with thousands of Semi-palmated Sandpipers and hundreds of Ruddy Turnstones and Red Knots present.  Dowitchers, Dunlin and Sanderlings had for the most part moved out earlier.

As to collateral birding this year, I would have to say that Clapper Rails and Seaside Sparrows were the the stars that held our attention the longest.  Both are considered hard to see, yet we found that both were quite willing to be seen extensively, given the right opportunity.

We will publish a formal report for 2009 in the future, but we wanted to keep you all in the loop.  And many heartfelt thanks to all for your encouragement,  advice and support.

Best wishes, Lanny McDowell

Here is a link to a general and somewhat optimistic newspaper summary from Philly:

http://www.philly.com/inquirer/health_science/daily/20090603_Biologists_hopeful_red_knots_have_turned_a_corner.html

The birds on this stretch of beach at Gandy’s were mostly semi-palm sandpipers.  They are feeding on horseshoe crab eggs along the rising tide line and along a shallow trough dug by GCA volunteers in the course of completing a study to determine how many more eggs become available to foraging shorebirds after the sand has been raked up.  Notice the diagonal line of birds, including some turnstones, which are feeding up the beach in the disturbed area above the tideline.

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Typically all the species shown here are willing to fly in mixed flocks.  I would say that Semi-palmated Sandpipers prefer to fly in a same-species flock.  More photos of them at a later date.

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Sanderlings can look pretty big next to semi-palms:

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Four species … and check out the leg bands:

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If you want to know how big is a single horseshoe crab egg, have a look at the beak of the Red Knot in this photo:

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These images and Lanny McDowell Avian Art fine art prints are available for purchase. Contact me or View my gallery.

Birds are cool!  Lanny

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Shorebirds: Red Knots and Ruddy Turnstones « boingbird.com
06.10.09 at 9:17 pm

{ 2 comments }

1

jake calvitti 06.18.09 at 7:26 pm

High School student from stone harbor interested in studying marine biology looking for some volunteering!

Thanks
jake

2

Lanny McDowell 06.19.09 at 7:00 am

Jake, How cool is that, that you found my blog and made contact?! In 2008 & 2009 we spent approx. one week in southern NJ across the peninsula from Stone Harbor. In 2008 one of the other GCA guys, Porter, and I would drive over to Stone Harbor around sunset to watch the knots and other shorebirds headed to roost. You live in a very dynamic part of the East Coast, nature-wise.

We hope to be back on Delaware Bay in oh ten. What we will be doing then, exactly, is not determined at this time. However, it should entail some application of what we have been thinking about and testing up to this point, namely, that there may be a technique or techniques that we could apply that would make more horseshoe crab eggs available to the feeding shorebirds. It sounds simple when you say it, but not only is the bay ecology complex, but the bureaucratic and political landscape may require attention as well. The experiments we conducted this year will hopefully lay the foundation for more large-scale projects in the future, assuming that there is a continuing need (likely!). The first non-official reports about the numbers of avian migrants showing up, at least Red Knots, and their departure rates were both trending optimistic after this season.

I do not think anyone would conclude that a better breeding and survival rate in the Arctic last year means the scary declines in shorebirds is reversing, any more than a dip in gas prices at the pump means that global warming is going away anytime soon. If GCA can develop, permit and apply useful strategies that help the birds put on fat, that could be a tool to use during years of lower survival or low HS crab egg production, until a time when the HS crab breeding population has rebounded to sustainable levels.

This year I was struck by how spread out all the birds were, moving back and forth along the beaches from feeding to resting to feeding locations. And it sounds like there were a lot of birds on the DE side this year. Last year we watched the knots feeding in a very concentrated group at Moore’s Beach. This year they were all over and so were the HS crab eggs.

As to volunteering, sure, I will bet we could use your help. The more we set out to do, the more hands we need. But most likely we are talking about May of 2010, so stay interested and stay in touch. Try me in March – it’s closer than you think – and I will bring you up to date on our plans.

Lanny

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