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This blog focuses on the conservation of wildlife and rural communities that depend upon them.  These blogs are meant to help people who care for wildlife and would like to join in the many efforts aimed at improving conditions for wildlife and habitat. Conserving wildlife not only helps animals but rural communities that rely on hunting, fishing, bird watching, and other outdoor sports to create an economy that overcomes the economic burden of living in important ecological places like Delaware Bay.

Conserving WildlifeDelaware BayDelaware Bay 2021

Letters to the Delaware Bay Team – update 2

by Larry Niles
written by Larry Niles

previous update

Dear Team,

A quick note to keep you up to date.

 

 We made our first catch today of 120 knots and a handful of turnstones.   It was a hard choice that worked out.  Over the last few days, the number of red knots stayed at about 600 and very few turnstones and about 1000 sanderlings.  The winds were blowing from the north and we assumed the problem was the adverse conditions for migration.  But we weren’t sure. Usually, we start on the 13th ( yesterday) but with so few birds we had visions of last year where the birds came and left because the crab spawn didn’t really get underway until the third week of May and ultimately peaked in the first week of June.  By then the Knots and other species had left.  Would this year be the same?  Did knots decline after last year’s delayed?

Red knots and ruddy turnstones feed on horseshoe crab eggs on the shoal between north Cook beach and south Reed Beach NJ. We trapped these birds successfully.

This year the water warmed slightly faster than last year. Still, the water temperature fell below 59 degrees in the morning, the threshold for crabs to spawn because nighttime air temperature fell into the 40’s. Through the week the crabs spawned in fairly good numbers at night and smaller numbers during the day ( the night water temperature is defined by the daytime air temperature, the daytime water temperature by the previous nighttime).    Even now the nighttime temperatures fall into the 40’s.

 

But eggs were building and so we assumed the problem was the adverse winds.  Just to be sure we didn’t trap yesterday ( the 13th) and instead carried out a boat count to be sure we weren’t missing knots in the areas between Bidwell’s and Maurice River.  We found only 30 knots and a few other species.

We also hit the rock jetty at Goshen creek and spent the afternoon struggling to get back to the dock.

 

This morning the number of knots jumped from about 600 to about 1000 and it seemed more came in this morning.  In the 120 we caught 10 recaptures ( which will warm Humphrey’s heart).  The winds are fair and from the south so we expect more in the next day or two. Tomorrow we go for Turnstones.
We also make a small catch of sanderlings at Villas, NJ.  We only caught 12 birds, two of which were named and released by Vivienne and Juliette Grime with help from their mother Janine.

 

Larry Niles and the NJ Shorebird Team

 

next update

Vivienne and Juliet Grimm hold two sanderlings as part of our catch. They named the bird’s Twinkle and Tweet Tweet.

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Conserving WildlifeDelaware BayDelaware Bay 2021

Letters to the Delaware Bay Team -update 1

by Larry Niles
written by Larry Niles

Dear Team,

I pray you are all healthy and safe in your home. We will miss those if you can’t come but I hope you will keep it open for next year.

This year we will probably have about a 12 person trapping team, plus 3 people working on eggs and two people working on resightings, and the sixth person working for Joanna conducting modest research of the stewardship project. So the team this year includes Stephani, Alindi, Charles, Ren, Susan Moody, the resighting team is Meghan Kolk, Faith Zerbe, and Riley Chenoweth Hafner,  the Egg team is Katherine Michell and Susan Linder. and Joanna’s tech Grace.  We are renting three houses to keep people at safe distances, although all are vaccinated.

There have been a number of changes to the bay sure and I will work so just list some in bullet form

 

  • Working with the American Littoral Society and Wildlife Restoration Partnerships ( Stephanie and I) have erected Sand berms in five locations that winter storms have either worsened breeches or create a new one on Kimbles Beach and pierces point. We closed the breach at Reeds that you may remember us rescuing 5000 crabs with a bucket brigade in 2017.  The winter has not been kind to the Bayshore.  The complete lack of any ice or snow and the normal ferocious winds from the west and NW have left most of the beach damaged.  Pierces was hit hard.  We have funding to redo Pierces next year and Fortescue but that won’t take place until next winter.

American Littoral Society erected sand berms to prevent horseshoe crabs from being pushed into the marsh behind the dunes through breaches created by storm waves.

 

 

  • I’d like you all to visit a new website for horseshoe crab recovery coalition. David Mizrahi and I began this two years ago and it has blossomed into a 30 group coalition including national wildlife and national Audubon, Physicians for responsible medicine, and corporations like Eli Lily. The group is dedicated to ending the killing of horseshoe crabs in various ways. This year we are instituting the first Atlantic coast-wide survey of horseshoe crabs.
  • The National Fish and Wildlife Foundation has funded us once again and the plan is to continue until 2028. The Foundation has guided our project through more focused metrics that include Horseshoe crab egg densities, an objective measure of the stopover that preceded the overharvest of crabs and thus provide a better comparison than many of the metrics chosen by the Atlantic States Marine Fishery Commission which chose all its metrics to start after the overharvest thus biasing the assessment.
  • The condition of the Horsehoe crab population is uncertain. The agencies suggest without good evidence that numbers are going up but any reasonable judgment based on the data suggests otherwise. The bay trawl done by state of Delaware shows promise though and so I am hoping for more crabs this year but prepared for the same.

A page from the “Draft Report to the Atlantic States Marine Fisheries Commission Horseshoe Crab and Delaware Bay Ecology Technical Committees” showing the status of adult and immature male and female horseshoe crabs as determined from a trawl offshore of the mouth of Delaware Bay. The report by Rujia Bi, David Hata and Eric Hallerman of Department of Fish and Wildlife Conservation at VPI. . Numbers fell in 2019.

 

  • So far the weather was cooperating with a warm spell that brought bay water temperatures up to the threshold for spawning at 59° (15° for you foreigners). But it is since dropped to below 57.   let’s hope for warmer weather.  There was some spawning but not many eggs yet
  • Similarly, the red knot population is uncertain. The counts done in Terra del Fuego remains similar to last year but with new observers. The count in Lagoa do Piexe in southern Brazil, was far below last year and is the count done in San Antonio Estes, Argentina.  So the data is mixed.  As of this morning, there are about 500 knots in the bay, 400 knots were at Cooks this morning.
  • We have purchased new equipment.  We have a new ATV that we purchased last fall and a new storage trailer that allows us to work inside if necessary. We are renting three houses again this year but you all will be happy to know that thanks to Stephanie, we have rented three for next year, a first!

We will begin trapping on Thursday I will keep you informed of the progress during the season.  I missed some people last year inadvertently, let me know if you see someone missing that might want to know.   Feel free to add your two cents, miss you all.  Larry 

next update

 

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Conserving WildlifeDelaware Bay 2021Restoring Habitat

Pierce’s Point Reflects The Bayshore’s Long History of Use and Abuse – and here how to fix it

by Larry Niles
written by Larry Niles

Pierce’s Point Reflects The Threat to all Delaware Bayshore’s Beaches – and Here’s How to Fix It

(see previous post )

We began our project fixing the oldest and most deadly breach for horseshoe crabs in the middle of South Reeds Breach. The dune gap allows the sea to gush through, pushing crabs into the marsh and certain death. The breaches also expand yearly, sometimes in a single storm, threatening the beach’s integrity. With additional funding from the National Fish and Wildlife Foundation (NFWF), we fixed four more gaps, three on Pierces Point and one on Kimbles. The three breaches on Pierce Point were the most difficult, as it is not three breaches but one long one that threatens the entire point and the town itself.

Like most of the towns in this area of the bay, Pierce’s Point sprung from a ramshackle community of locals who came to Pierces to enjoy the bay’s fishing, crabbing, and, for the hardy, swimming. Over time, however, the town followed others shoreline communities down a path of ever-increasing property values and a shift to people from all over the region. Houses grow bigger every year, and every year the threat from the seas grows.

Hurricane Sandy whacked Pierces in 2012, and our team, led by the American Littoral Society, restored the beach in 2014. The beach held the sand for several years, but gradually, the sea has worn it down to its present depleted condition. 

aerial showing the dune breaches on Pierces Point NJ

This drone shot shows the breaches in the dune along with Pierce Point Nj on Delaware Bay. The breaches expand each year and threaten to connect with the Dias creek which would likely result in the destruction of both beach and marsh.(move over image to remove caption)

 

 

 

 

 

A winter storm pounds the beach at Pierce Point NJ. Previous storms pushed the beach inland creating three big overwashes.  The town of Pierce’s Point shows just in the upper right of the picture.

 

 

The Increasing Threat of Climate Change

One reason for the loss comes from the ever-increasing threat of Climate Change. Winter storms have grown in frequency and severity, and as the bay warms, winter ice that usually forms along the shoreline has all but disappeared.. The impact is dramatic. Without floating ice moderating waves or ice chunks taking the brunt of storms, the beaches struggle to hold sand from being pushed into the marsh behind. The first map below compares drone shots taken in late Jan and mid-March. In just two winter months, the shoreline moved inland significantly.

And this is not a one-time event. The second graphic is a series of aerial photos showing change since 1931. You can see not much changed until the 1990s, but afterward, the peninsula eroded quickly. The last image is a projection of only ten years. 

Our project is a bandaid on this coastal wound. The last three years have opened up gaps in the beach, accelerating the beach movement towards its final collapse into the tidal creek that runs along the inland side. Our reconstruction of the damaged sand dunes will close those gaps. This will also prevent horseshoe crabs from flowing into the gaps and dying when they can get back out. But our work is a stopgap meant to stop the damage. 

 

In these drone photos, you can see erosion that took place in just two months this year.

 

 

 

 

 

 

 

Phil Heun, a third generation heavy equipment operator pushes sand on Pierce’s Point NJ to fix dune breaches

Fixing dune breaches at Pierces Point NJ

 

 

A More Lasting Solution

In the works, however, is a more long-lasting solution. With funding from the NFWF, we will provide greater protection and long-term resilience with the use of stone breakwaters. In Pierces and three other locations, we are pursuing permits for the construction of hybrid stone breakwaters that will provide both protection and improve the ecological productivity of the bay. 

Breakwaters are old technology but tried and true. For example, in the early 1900s, as in most of the bay, farmers built dikes to keep out the tide so they could farm the marsh along the upper bay shoreline around Elsinboro at a historic site called Finn’s point. In the first graphic below, you can see these dikes in a 1931 aerial photo of the area. Finns Point is just visible at the upper right corner. In the middle aerial photo taken in 1940, you can see two important features. First, the farmers abandoned the diked fields, and the tide overwhelmed the site and threatened the inland communities. In response, the community built stone breakwaters to replace the farmer’s earthen dikes. You can see the result in last image of the series from a 2017 aerial – the breakwaters remain, and the protection allowed the marsh to recover.  

Compare this will the sad fate of Cox Meadow just east of Moore’s beach and west of West Creek in the second graphic below. There too, farmers abandoned earthen dikes, but no one came in to replace them. The result is a slow-moving ecological catastrophe. The vegetation quickly eroded away, and the resulting mudflat expands every year, consuming productive marsh and threatening the inland communities with storm surge and flooding. This could have been prevented with breakwaters.

Our work at Pierce’s will help end this period of great erosion of the bay and hopefully create a more stable future for the next generation of people who care for the bay.

 

 

Sometime during the Great Depression, agencies rebuilt the abandoned earthen dikes of farmers who used the drained marsh to grow crops. The crops can be seen in the first photo taken in 1931. The second photo taken in 1940 shows the destruction of the marsh after the farmer abandoned the dikes. It also shows a stone breakwater that must have built in response to the loss. The breakwater exists to this day as seen in the third photo taken in 2017. Without the stone breakwater, the marsh would have been destroyed, as happened in Cox Meadow described in the next figure.

 

 

Three aerial photos taken in 1971, 1991, and 2017 show the relatively rapid destruction of beach and marsh at Cox Meadow on Delaware Bay caused by the abandonment of salt hay farm dikes without any response.

 

 

 

 

 

 

 

 

 

 

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Conserving WildlifeDelaware BayDelaware Bay 2021Restoring Habitat

Fixing a beach that kills horseshoe crabs

by Larry Niles
written by Larry Niles

Horseshoe Crabs too Cold to Spawn

In May of 2017, horseshoe crabs would not spawn. Shorebirds came to the bay in mid-May as usual, but they found too few eggs to remain. With unique leg flag codes, Red Knots were seen in NJ one day and would turn up in Massachusetts the next. The cause for the delay – the bay’s water temperature refused to climb to the threshold necessary for cold-blooded crabs to get hot bloodied enough to spawn -59 degrees.

The bay water heats and cools counterintuitively, building hopes and then with the next tide extinguishing them. It falls in the day ( after a night of cooling) and goes up at night ( after a day of warming). It would warm with a cool northwest wind (slowing down incoming cold ocean water at the bay’s mouth) and get cold with a warmer southeasterly wind ( by pushing in cold ocean water). Without crabs spawning, the knots and other shorebirds were going to have a tough breeding season.

 

A Deadly Storm Pushed Crabs to their Death

Eventually, warmer weather brought rising water temperatures. A modest daytime spawn on the 17th promised a better spawn during the subsequent higher nighttime high tide. That evening as the tide rose higher and higher, a storm loomed ominously in the distance. Crabs came ashore in tremendous numbers, and the beach finally started to fill with eggs. Eventually, the storm hit in the dead of night with a gale-force westerly wind slamming against the Cape shoreline and whipping up waves usually seen on the Atlantic Coast. Although it lasted only 30 minutes, the storm caught crabs just at the wrong time.

 

 

Horseshoe crabs spawning on Reeds Beach NJ in 2017

 

The following day we saw the storm had overturned thousands of crabs on the beaches. Fortunately, teams from the volunteer group, Return the Favor, acted quickly to rescue many of the crabs from suffocation and dehydration by carrying them to the shoreline.  But the storm had far more significant impacts. The onshore winds hit just exactly at high tide as horseshoe crabs gathered to spawn, and in places where the sea has eroded gaps in the dune, the wind pushed water and crabs into the marsh behind the beach. When the tide fell, the crabs remained, trapped in the tall reeds piled atop each other

 

Fixing the Gaps

The worst overwash of crabs occurred on South Reeds Beach. There was a happy ending for those crabs because we trapped the beach that day and saw the carnage. Quickly the NJ Shorebird Team organized a bucket brigade and rescued over 5000 crabs.

The NJ Shorebird Project team rescues horseshoe crabs in 2017.  A storm the previous night pushed crabs through a breach in the dune into the marsh behind. Without a flooding tide, tall marsh grass traps the crabs who eventually suffocate and die. The team rescued nearly 5000 crabs

 

For all the other places, crabs just died. And this is the focus of the American Littoral Society and Wildlife Restoration Partnership restoration work. Last year, the National Fish and Wildlife Foundation granted our group funds to fix the eroded gaps in the Bayshore’s low dunes, where crabs will most likely overwash and die. The work carried out by JR Heun of H4 Enterprises will place 5000 tons of sand into four gaps known to strand horseshoe crabs: Reeds Beach, Kimble Beach, and Pierce point. Follow this gallery of pictures to understand the work.

( see next post)

 

reed beach fix

Overhead view of Reed’s beach shows a front-end loader moving a ton of sand to fix a break in the dune damaged by storm tides. The high seas flow into the gap, pushing horseshoe crabs into the marsh, where most die from suffocation. . The breaches also diminished the beach’s defense against the sea. The machine operator JR Heun placed over 700 tons of sand to fix the breach.

 

 

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Conserving WildlifeDelaware Bay 2020

Praise for volunteers taking care of Delaware Bay’s horseshoe crabs and shorebirds

by Larry Niles
written by Larry Niles

 

previous post

The Delaware Bay Shorebird Project in NJ alters the boundaries established in the most US conservation efforts.  Instead of relying heavily on paid staff, instead, it incorporates responsible and professional volunteers into every aspect of the work.  How did it evolve into this, how does it compare to other staff dominated projects?  How did volunteers perform their passionate tasks?

 

Monitoring vs. Management

Usually, agencies cleave the science of conservation from efforts to restore or manage. In other words, the biologist assessing the health of a population with surveys or research acts independently of those implementing programs to restore wildlife or habitat, like increasing forage or rebuilding damaged habitat.

Of course at the heart of the distinction is money and politics. Agencies and foundations prefer funding management over monitoring, especially long-term monitoring, which has no point other than informing management. Politicians want research and monitoring separated from management because it allows more political influence in controversial management projects. This fear of data is why congressman Jeff Van Drew, opposed the creation of a saltwater license in NJ with a $10 fee. By denying Marine Fish Agencies funding to do critical monitoring of fish stocks, Van Drew gave permission to the seafood industry to take without regard to the damage caused to fish populations or make a fast buck at the expense of the recreational fisher economy of marinas, bait shops, restaurants, etc. 

 

Democratic Congressmen turned republican Jeff Van Drew meets with Trump. Van Drew prevented NJ from enacting a salt water license and with it the new funding that would help biologists determine the impacts of industry abuse from overfishing sportfish stocks, forage fish and unrestrained bycatch.

 

But this separation of monitoring and management defines most conservation groups as well, mostly for financial reasons. Those with research and monitoring arms, like NJ Audubon, usually keep research and monitoring separate from the better-funded management side of the group. Most funders prefer to fund management like habitat restoration rather than monitoring or research because they believe its a more direct approach to helping wildlife. Long term monitoring rarely receives sufficient funding.

Adaptive management and monitoring

The ideal should be an approach collectively known as adaptive management, formally known as Adaptive Resource Management ( ARM). In ARM, both management and monitoring come together to inform better management. These projects embed tracking metrics that describe the management and theoretically provide useful guidance on conducting the project while in progress or for the next project. I belong to an ARM effort at the Atlantic States Marine Fish Commission. It attempts to relate fishery statistics to those from birds, to manage the horseshoe crab harvest adaptively.   

 

 

Unfortunately, most adaptive management monitoring is an afterthought or guided by biologists hoping to collect data for existing projects and only nominally associated with the management. Usually, the data collected doesn’t affect the current management effort because monitoring biologists have little standing in the command of the project. Most often, the monitoring results don’t guide future projects either because the monitors rarely publish the data they collect, so it sits useless in unpublished project reports or virtual file cabinets.

 

Defying standards

Our shorebird project was formed under unusual circumstances and so evolved into monitoring, research, and management being tightly woven together as one effort. It started when in 1997 Clive Minton, Allan Baker, and Humphrey Sitters led a gaggle of shorebird scientists to the shores of Delaware Bay following a month of trapping the same shorebirds in South America where the birds started their yearly journey. The scientists were all professional, but most in some other expertise.  Clive’s earned his Ph.D. from Cambridge in metallurgy while Humphrey Sitters earned a living as a lawyer.

Clive Minton and Larry Niles on Cooks Beach NJ 2006. Clive first came to the bay in 1997 and helped start our project that lasts to this day

 

 

The group arrived just as Governor Christie Whitman and her aid Judy Jengo fought NJ Fish and Wildlife’s Marine Fish Council who refused to head off the carnage of two and half million horseshoe crabs spawning on Delaware’s shores.  As chief of the NJ Endangered Species Program, I had to argue the case for a moratorium to the council. I used the data collected by our shorebird project team collected that year. We achieved a moratorium in NJ, but the battle continued as other states took Delaware Bay crabs.  This turned out to be the beginning as new threats emerged.

 

Too many threats too few biologists

We had to protect the foraging birds from the great number of people coming to the bay to see the birds and crabs but unaware of the bird’s needs.  Photographer’s hunted birds down for good pictures, daytrippers out for an ecological thrill tried to get selfies close to the birds, or sport fishers who cared only to catch fish took over beaches.  All focused on their pursuits regardless of the impact on birds.

After Hurricane Sandy pounded beaches and swept away 70% of the optimal habitat, we had to restore them and used shorebird project data to help guide the projects. Oyster farmers used their insider status to change the rules of protecting intertidal habitat to expand oyster aquaculture without regard to impact. We had to initiate the battle to stop them from developing into every suitable horseshoe crab habitat. Shorebird project data played a big role in the USFWS Programmatic Opinion that protected the intertidal zones after state agencies yielded them up for exploitation.  Lysate bleeding companies located in other states but taking blood from Delaware Bay horseshoe crabs without any substantive or restrictive regulation. Here too horseshoe project data help underpin conservation group efforts to rein in the needless overbreeding and killing of crabs.

All of these battles didn’t come and go but came and grew. We needed to collect data because it was our only way to stop persistent political efforts to take these economically valuable public trust resources to industries that care nothing for ecosystem health or population viability. So we needed to continue collecting data on shorebird numbers and their condition each year. We needed to track horseshoe crabs and their egg densities. We needed to stop people from chasing shorebirds. We needed help and lots of it.

Volunteers fill the gap

But how to do all this work when no one wants to pay? Clive brought an answer to this fundamental problem bedeviling most wildlife conservation projects in the US. In his experience, wildlife conservation started with smart, well trained conscientious volunteers. They carried out most of the work of monitoring because they loved birds and the work. But they also took the time to ensure the monitoring would provide others the basis for protection often without government involvement.

For example, he helped start the Broome Observatory nestled squarely in Australia’s desolate and deadly northwest coast near Darwin. He trapped shorebirds there with a legion of volunteers who paid for all the expenses. We took part in Clive’s banding campaign in 2008. We banded thousands of shorebirds of many different species and collected valuable data on all of them. The project anchored biologists’ work in many countries in the Australasian Flyway, including the tremendous ecological battle to save the wetlands of the Yellow Sea, a Delaware Bay-like stopover in that flyway.

 

The Broome Observatory anchored extensive and numerous biological investigations relying heavily on Clive’s banding and survey data as well as tracks from transmitters and geolocators attached during the trapping expeditions. Broome also employed a warden to protect shorebirds around Broome as well as an 80-mile beach. , a NJ size stretch of Australia’s west coast where one “never worries about the sharks because the saltwater crocs eat them all.”  On this wild and completely uninhabited beach, millions of shorebirds spend the austral winter. The protection conducted by Broome Observatory wardens relied entirely on the volunteer-driven data collection with modest support from the Australian government.

AllTrapping shorebirds in Australia's Broom and 80 mile beaches

 

a new perspective on the protection

From this perspective grew the Delaware Bay Shorebird Project in NJ. Our paid team ensures the majority of the funds go to support the volunteer effort.  Each year people come to the bay to help in the trapping and monitoring. This largely volunteer team conducts a yearly assessment of bird numbers and condition, a yearly assessment of horseshoe crab eggs and horseshoe crab spawning, yearly surveillance of avian influenza, yearly tagging with tracking tags, geolocators, transmitters or satellite transmitters depending on the year.

At the same time, these data and funds help inform and support volunteer stewardship programs ( Conserve Wildlife Foundation of NJ), a crab rescue program ( Return the Favor), and a beach restoration program ( American Littoral Society). Also, the data is being used in policy and regulation by helping to set the quota for the harvesting of horseshoe crabs, and assessing the impact of oyster aquaculture.  It also helps guide the protection of shorebirds while feeding on Bayshore beaches. Paid staff and volunteers erect fencing and signs and then steward the beaches. 

 

Praise for the volunteers taking care of Delaware Bay’s horseshoe crabs and shorebirds

I speak for the NJ Shorebird team in saying we are indebted to the many volunteers that take part in this work. Stewards religiously help people understand the need to allow the shorebirds time to feed and all but a few find satisfaction in just seeing the birds from behind the posted barrier. Volunteers also rescue crabs as part of Return the Favor. oftentimes they are the same people, who both steward beaches, overturn crabs and help with the Shorebird Team.   Allowing birds to feed accomplishes the primary goal of the project.  The data collected by the volunteers like estimating the number of red knots in the bay or the resighting of unique ID leg flags allows population estimates and aids in tracking individuals around the hemisphere. Volunteers from Citizens United to Protect the Maurice River cooked dinner for us nearly every night and left us with fixings and leftovers that kept feeding us at lunch and for snacks.  

All this was done remotely, of course, because of the virus. We saw people but could only utter face mask distorted thank you and brief updates as to what is happening. It was one of our greatest disappointments not to thank these beautiful people who braved the virus to leave their homes and provide scientists, birds, and crabs care in a grave time in our nation’s history. 

 

Volunteers resighting shorebirds, stewarding protection, flipping crabs, and feeding the Shorebird Teamors
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Conserving WildlifeDelaware BayDelaware Bay 2020

Close to the Finish Line

by Larry Niles
written by Larry Niles

Previous Post

Direct Flight to the Arctic or Stopover?

A migratory stopover for arctic nesting shorebirds must provide each bird the energy necessary to get to the next stopover or to the ultimate destination, the wintering or breeding area. Delaware Bay stands out among these shorebird refueling stops because it delivers fuel in the form of horseshoe crab eggs giving birds options. Our telemetry has shown that Red knots, the species we best understand, may leave Delaware Bay and go directly to their Arctic breeding areas, or stopover on Hudson Bay. The choice of going straight to the breeding area or stop at another stopover may be critical to understanding the ecological dramas now underway on Delaware Bay.

This year has been like none of the 23 years we have studied shorebirds and horseshoe crabs on Delaware Bay.  As I described in these updates, persistent northeast winds caused two unusual conditions that affected red knots and the other shorebirds species, ruddy turnstones, semipalmated sandpipers, dunlin, short-billed dowitcher, and sanderlings. First, the wind blowing in from the cold ocean chilled the bay and slowed the horseshoe crab spawning to nearly a standstill until the last week of May. Whereas in other years, we would have seen tiny ribbons of eggs threading the tideline, this year we have none. Shorebirds depend on this natural largess, gobbling eggs with almost no effort and laying down weight like starving people at a fast-food restaurant.

Horseshoe crab eggs on Kimbles beach

 

 

Instead, this year they must hunt them down by scouring the bay for any odd pockets of crab spawning. Not only is there not enough, but the search burns valuable energy reserves that should ultimately go to the flight to the Arctic and breeding.

The second impact of the odd weather events of May came when Tropical Storm Arthur pounded the Southeast coast and generating a prevailing northeast wind along the entire coast. This blocks migration north. We can only guess this impact because COVID19 precautions prevented us from attaching tracking devices on red knots stopping over in Lagoa de Peixe in southern Brazil. Like Delaware Bay, LDP prepares birds for a long flight but to Delaware Bay. We have tracked red knots flying nonstop for almost 6 days to reach Delaware Bay. Attaching nanotag transmitters in Brazil would have helped us understand the impact of the storm on the birds. Instead, we must guess to what extent tropical storm Arthur impaired migration.

 

Flightpath of the red knot with geolocation TVV. See the 5.5-day continuous flight to Delaware Bay. Map by Dick Veitch

By the Numbers

We can usually figure out the Delaware Bay stopover story through numbers, but this year added a new twist that came with significant uncertainties. We typically see the first flock of red knots by May 12, a second, and a more significant influx the following week and nearly all by May 23. So last year, for example, we saw about 3000 knots, then 12000, and finally 30,880.

In contrast, this year, we only saw a few hundred by May 12, and by May 23 we never had more than a few thousand in each state. We judged this a consequnce of the Tropical Storm delaying shorebird arrivals.   Surprisingly when we did our first baywide count counters in NJ and DE found 19,397 knots. As I discussed in an earlier update, did these birds arrive, or had we missed them?

Delaware Baywide count of red knots and ruddy turnstones

 

The answer came by May 26 when we did our second all bay count ( only 2 days later) and found only 6000 knots. Our subsequent search turned up less each day. Today we saw about 200 on the NJ side.  This suggests that not only had the large group left, but so did all the others.

At the same time all of this was happening on the bay,  we also saw 6500 red knots roosting in Stone Harbor during the second week of May. That number dropped to 2000 then finally to about 500. Were these part of the birds found in the May 24th survey?  We have also received reports of Red knots in other places along the Atlantic Coast NJ, like Malibu Beach NJ and Forsythe USFWS Refuge suggesting birds moved from the bay to Atlantic Coast sites where they could feed on clams and mussel spat.  Although sufficient for birds needing only modest weight gains, it is unlikely to satisfy the needs of the long-distance knots that must recover large amounts of weight to continue their migratory flight.

 

Leaving Delaware Bay for Other Places

From all this, we conclude the pulse of birds,  seen in our first count came late to the bay were delayed by Tropical Storm Arthur, arrived and found few eggs, then left for other places along the Atlantic Coast.

Still, the departure puzzles us. Weather slowed crabs spawning until four days ago, and then water warmed enough to stimulate dense crab spawning in more areas and higher numbers. The last few days have been epic, as though the delay had pent up the need to spawn. Crab digs now pockmark most beaches and shoals. Our egg count shows this sudden increase starting at about May 24. The bay water temperature at the Cape May Bouy explains this change in spawning intensity. It showed water temperature reaching the threshold to elicit a good spawn at about the same time we saw more spawning and counted more eggs.

horseshoe crabs eggs counted in the last three weeks of May 2020

 

Yet, most beaches remained empty of birds. We made a catch of red knot on May 27, from among a very small group of knots. This sample would describe the weight gained by red knots that had been in the bay for the last few weeks. 70% of the red knots weighed less than what they need to fly to the Arctic and successfully breed or 180 grams.  Yet all are gone by today May 29th.

 

The weight distribution of red knots caught on Baycove Beach NJ, May 27, 2020

 

Delaware Baywide count of red knots and ruddy turnstones

Crabs spawning at Moores beach creek NJ

 

 

 

 

 

 

 

 

Horseshoe crab nesting depressions on Reeds Beach NJ 2020. Note the absence of shorebirds

So Why Leave?

So why did they leave?  The scientific literature points out that when migratory birds arrive in a foodless stopover, they leave for another. The rule is ironclad. Get to the breeding areas in as little time as possible.  When facing beaches devoid of eggs, it’s apparent the birds choose to move on.  Too bad they did so just prior to the emergence of abundant horseshoe crab eggs.

Fortunately, these unfortunate birds still have options. They can stopover in one of the Hudson Bay stopovers, as I described in the beginning. Even then, they can choose not to breed and turn around.  They also may die as we demonstrated in this paper by Sjoerd Dujins

There is still the possibility of birds arriving late. Our work will continue until the bitter end. If late birds arrive, we will know.

 

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