Tag: Delaware Bay Shorebird Project 2016

One in a Series of Updates on the 20th Year of the Delaware Bay Shorebird Project

by Dr. Larry Niles, LJ Niles Associates LLC

On our final effort to trap shorebirds on Delaware Bay, we had the remarkable opportunity to watch sanderling and ruddy turnstones lift off for the Arctic. We first saw them feeding on the wave-tossed shoreline within the protected area in Villas; 1500 birds weaving as a single thread 5 deep with the contours of the wave, acting like a flying flock on the ground. Then a disturbance, a crow flying low down the shoreline and 2000 birds fill the sky.  Most settled again but one group of about 300 flew more with greater determination than the rest. Still low but gaining altitude the flock wavered, and a mutinous band peeled away deciding against the departure returned to the safety and abundant crab eggs on the shore just north of us.  The other 150 grew more determined, more structured and rose slowly as they powered their way north. Then they disappeared into the Northern sky.

 

Shorebirds departing Delaware Bay for their Arctic home, 2500 miles away stand as one of the most awe-inspiring and rewarding parts of our stopover project. They usually start in the early evening under a blue sky drenched with the glow of the setting sun and continue until near dark.  They almost always go with a favorable southerly breeze and at least a clear sky in the north.  Thousands of all the species after getting fat on the Bay’s bounty of horseshoe crab eggs – red knots, ruddy turnstones, sanderling, semipalmated sandpipers, short-billed dowitchers and dunlin –  lift slowly as they fly along the Cape May peninsula coast towards Dennisville and beyond.

 

They are dangerously overloaded with fat. Two birds highlighted the importance of this.  On May 30 we caught 97 knots, 168 sanderlings and 75 ruddy turnstones.  Among each species were individuals of extraordinary weight.  One bird weighed 242 grams, fully 120 grams higher than the fat free weight!  They cart this load, like a plane with extra gas tanks, to fly two days to the Arctic islands of Canada.   Imagine for a moment – you weigh 150 pounds and gain an extra hundred and fifty, then try to go anywhere, especially for 2000 miles.

 

In this video one can see all the different body shapes – and weights – of red knots and other species on Cooks Beach shoal.   It’s easy to see many birds are ready to leave.

 

The fact that they can do this is a marvel of flight bio-engineering.  While building weight they prepare like weight lifters, increasing muscle mass, heart size, and lung capacity.  Close to leaving, they decrease the organs of digestion just to squeeze in the last few grams of fat.  Then they wait for good weather, lumber into the sky and go forth into the vast north.

 

2016 was a good year for the shorebirds stopping over on the New Jersey coast. Most came in better-than-average condition, so they had a head start.  The early spawn was strangled by cold water which seemed to hover around the temperature threshold for spawning- 59 degrees F.  Tellingly however, the crabs spawned with gusto on the beaches from northern Reeds to Pierce’s Point. There the five inter-tidal creeks and inter-tidal flats warm the water that washes over spawn-inviting shoals and newly restored beaches.  Throughout the stopover a majority of the bay’s population foraged on the eggs laid by vigorously spawning horseshoe crabs.  On one day we saw a 10,000 red knot flocks on North Reeds Beach happily roosting and feeding on the abundant eggs.

 

 

Eventually the spawn accelerated and expanded but the birds still needed to get to the eggs.  If constantly disturbed by people, they will move endlessly often to lesser habitat if only to avoid disturbance.  In New Jersey we prevent this. Each year for the last 15 years, the New Jersey Division of Fish and Wildlife in collaboration with Conserve Wildlife Foundation of New Jersey, close the beaches important to crabs while leaving small observation areas open to the public.  The impact is non-intuitive but positive.

 

The closed beaches allow shorebirds to gorge on eggs unmolested by people: photographers and birders wanting to get one step closer for the perfect picture, compassionate people wanting to overturn crabs left stranded by the tide, or fishermen wanting to cast for the stripers that run in May.  All with good intentions they scatter birds and force them to fly to other less suitable and less accessible beaches losing valuable gained weight in the process.   The closures allow the birds to stay in the best places and eat like kings.  Paradoxically the bird photographers and watchers end up with even better views because the birds adapt to the settled threat. Even fishermen find enough space to fish from the observation areas.

 

At the height of the season people could come to one of the five observation areas in the Reeds, Pierce’s Cove and see flocks of nearly 30,000 shorebirds including 14,000 red knots – two thirds of the  whole population in the bay this year (as determined by air and ground counts).  Photographers, birders and inquisitive people had a wonderful experience and the birds got fat.

 

Despite the difficulties caused by the unusually cold spring, most birds of the three species we follow reached good departure weights and by May 26^th they started to leave. By June 1^st most were gone and by June 2^nd we advised reopening the beaches, 5 days earlier than the usual June 7^th opening.

 

Our team of scientists, managers, students, volunteers, and stewards deserve praise for all the various projects and research conducted throughout the season, from cannon netting and bird study, resightings of previously banded birds, research on shorebird movement, research on oyster reefs and structural aquaculture, monitoring of horseshoe crabs, monitoring crab egg densities, volunteer efforts to rescue stranded crabs, to steward protected areas and tag crabs. Also, the volunteers of Citizens United to Protect the Maurice River deserve a special thanks for their logistical support for our team, they prepared over 20 dinners for 30 plus people every night of our project.  Birds and Scientists all gain weight in May!

 

They all deserve gratitude, from the birds and horseshoe crabs, the people who love birds and horseshoe crabs and the people who love Delaware Bay.

 

 

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

One in a Series of Updates on the 20th Year of the Delaware Bay Shorebird Project

by Dr. Larry Niles, LJ Niles Associates LLC

We conducted our first bay-wide count of shorebirds on Delaware Bay and the results suggest we are rapidly approaching the peak number of shorebirds. Last year, we counted 24,700 knots and 16,000 ruddy turnstones. This year’s counts are lower because it’s earlier, but we are still over 20,000 knots and 16,000 turnstones, and 10,000 sanderlings that have stopped over in the bay. These promising results are preliminary, but it seems we are getting close to our peak population of red knots and at the peak of the other two species – if populations are similar to last year.

Bird condition also looks promising. Our catches show average weight increases for red knot compared to past years, which is good news given the very spotty horseshoe crab spawn. Ruddy turnstone average weights have increased considerably, the best in the twenty years we have been trapping (see the graph below). The distribution of these weights reveal more.

If we sample the same bird population with our cannon net catches, one would expect increasing average weights but similar distribution of weights – the same proportion of different weight birds, all getting higher. If a new group of birds arrives in the area, then one would see a new distribution of weights, only lower than the group that has been in the area longer. This can be seen in the historgram for ruddy turnstones below. The historgram supports our assumption that a new group of turnstones has arrived in the bay and are busy gaining weight. Based on our last catch, the distribution of knot weights shows no new arrivals, however the aerial survey and ground counts done after the catch point to a new group yet to be sampled. To our team of biologists this data is food for hungry minds. Within a few days, all will be revealed.

The actual distribution of the birds in the count tells another important story – the importance of the beaches and creeks between Reeds Beach and Pierce’s Point. This 3-mile section of Delaware Bay accounted for more than half of the entire population of red knots on the bay and outsized portions of the other species. This has been consistent through this season and over the last three years – ever since Conserve Wildlife Foundation (CWF) and American Littoral Society (ALS) restored the four beaches with new sand.

The restoration of these beaches avoided a potential disaster caused by Hurricane Sandy, which not only destroyed seventy percent of all the suitable horseshoe crab habitat on the New Jersey side of Delaware Bay, but it did much more. South Reeds Beach tells the story.

 

After the hurricane ripped through the area and pounded Reeds Beach with punishing westerly winds, most of the sand had been pushed off the beach and onto the marsh behind it. This unveiled a long standing and nearly impervious layer of rubble, remnants of long abandoned houses, bulkheads and the access road connecting them. We had no idea this laid beneath the sand of Reeds Beach South, but it explained why it never had good crab egg densities. Crabs couldn’t burrow deep enough to lay eggs.

The CWF and ALS restoration teams with funding from the United States Fish and Wildlife Service (USFWS), National Fish and Wildlife Foundation (NFWF), the Geraldine R. Dodge Foundation and Community Foundation of New Jersey, along with other groups, removed the rubble and laid down a beautiful sandy beach.  Every year since, horseshoe crab egg densities were among the highest in the bay.  This, of course, attracted higher than average shorebird numbers which greedily consumed the newly available trove of eggs. Similar work was done at Cooks, Kimbles and Pierce’s beaches.

 

However, the restoration work did even more. Sand naturally erodes from these beaches just as it does on the Atlantic Coast beaches. The sand lost at Stone Harbor and Avalon beaches, for example, ends up in Hereford Inlet. The same happens on Delaware Bay beaches and the eroding sand flows into the the nearby creeks forming beautiful crab spawning shoals. I described their importance in the Reeds – Pierce’s Cove in the previous blog. These creek shoals represent the best habitat in the bay, because they are loose sand, create small inner protected areas loved by spawning crabs and are washed by warm water flowing out from the small intertidal water drainages. Early season spawning almost always occurs in or near creek mouth shoals. Thus, even sand lost from restored Delaware Bay beaches goes to a good end.

One more characteristic, perhaps the most important feature, is that all these beaches, creeks and their shoals together create a small and very important landscape within the overall Delaware Bay landscape. The overall warming creates the best early season habitat for crabs and shorebirds and the continued volume of spawning maintains the value throughout the season. We now have over 10,000 knots on these beaches and thousands of other shorebirds.

 

All of these important natural features are greatly strengthened by the New Jersey Division of Fish and Wildlife’s restrictions that keep people from disturbing the birds. Without them, visitors, even those with good intentions, may disturb the birds from feeding.  The restrictions are implemented without conflict by a very cheery and passionate group of volunteer stewards who explain the importance of letting the birds take advantage of good habitat. Ironically, the Reeds to Pierce Cove still attracts the most people in the bay because they can easily see the birds from access areas provided at each of five road ends and the Bidwells Creek jetty.

 

All in all, it’s a shorebird’s – and shorebird lover’s – paradise. But soon it may be a paradise lost.

 

This year, state and federal agencies permitted thousands of structural aquaculture racks to sprawl over this wonderful shorebird habitat. If all goes according to their plan, soon ATV’s will be rolling all over the intertidal area, disregarding their long-term impact. Welded rebar racks will stop some a portion of the crabs from reaching the beaches, and more importantly impair their return. More and more crabs will fail to breed or die as gulls tear apart crabs stranded on the intertidal shore. Like much of New Jersey, this beautiful cove has the potential to be degraded by runaway commercial exploitation.

There are ways to expand aquaculture without destroying shorebird habitat. This is not one.

 

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

 

One of a Series of Updates on the 20th Year of the Delaware Bay Shorebird Project

by Dr. Larry Niles, LJ Niles Associates LLC

In spite of the very spotty horseshoe crab spawn, the shorebirds on Delaware Bay seem to be gaining weight on schedule. Below you will find a graph composed of the average weights of all the red knots by our team for the last 20 years. The curve is the result of combining all the data we collected and shows the sweet spot for most knots. As they arrive, they take time to gain weight but after about 5 days they start gaining weight rapidly. After the 26th or so, birds start reaching the critical weights necessary to safely reach the Arctic breeding grounds. One can see the curve deep at the end of the month because fat birds fly off leaving the less fat behind. In general, weights above the line are good, below the line not good. The large squares on the graph are the average weight of this year. So far, so good.

This is a bit of a surprise for the team. The weather here on Delaware Bay is wet and cold. The water temperature struggles to lift above 59 degrees, the temperature necessary for a crab to spawn on Delaware Bay. So far, the temperature has been below 59 degrees more than above. We had good spawns in the last few days, but only in key places.

A key place for horseshoe crab spawn happens to be the mouths of small creeks. The New Jersey side of Delaware Bay is blessed with many small intertidal creeks, most draining only marsh or small inland watersheds. Some of these creeks have names, Goshen Creek, West Creek, Nantuxent Creek, but many do not. Almost all have shoals at their mouth with the bay because bay currents, tidal flow and wind driven waves act against each other to settle sand coming from adjacent beaches or from inside the creek drainage. Much of the sand lost from our restored beaches settles into these shoals. For horseshoe crabs, these shoals are sweet places.

Usually, the shoals lie just under the high tide line and are composed of large grain sand, the optimal conditions for a good crab spawn. However, the most important characteristic and key to this unusually cold May, is the warming water flowing out from the marsh drainages. On a flooding tide, colder warmer flows into the vast marshes of the Delaware Bay. This warms the water. On an ebbing tide, it flows out the creek and over the shoals, making them slightly warmer and more conducive to inducing crabs to spawn. Even on these cold days, they literally climb over themselves to breed on the shoals. The shoals also protect the inner mouths of the creeks thus making the sandy shores at the mouth of the creek a crab spawning heaven.

However, as it seems usual with this blog, there is a growing concern. Right now, most of the red knot population on the bay is feeding on these shoals along with thousands of other species, but only half have arrived from southern wintering areas. We now have about 12,000 red knots on the bay and in a day or two we should find another 12,000 falling from the sky. Will there be enough eggs? Will the water temperature finally reach normal levels? These are the important question for the next few days.

 

Learn More:

• Conserve Wildlife Foundation’s Delaware Bay Shorebird Project
• Conserve Wildlife Foundation’s online field guide: Red Knot

 

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

One of a Series of Updates on the 20th Year of the Delaware Bay Shorebird Project

By: Dr. Larry Niles, LJ Niles Associates LLC

It’s well known that the Delaware Bay shorebird stopover depends on horseshoe crabs, but few know that Delaware Bay is a near perfect horseshoe crab habitat.

 

There are many places on the eastern seaboard where horseshoe crabs breed. Most are too small to provide sustenance for energy-starved shorebirds. Places like Cape Romain Refuge in South Carolina have enough horseshoe crabs so that one breeding female unearths eggs of another and thus lays out a tidy meal for shorebirds. But the areas are small and at this time unimportant to the population of shorebirds. Most of the others are too small to have eggs reach the surface. Its only in Delaware Bay where crab numbers reach into the millions and spawn in such great numbers that they spread like a carpet over nearly all beaches from Gandy’s Beach to Villas, approximately 20 miles of spawning habitat. The number of eggs and ultimately hatched young reach staggering numbers.

The huge population of horseshoe crabs on the bay is no accident. The bay almost seems built to suit the crabs. Crabs need beaches with large and deep sand flats, allowing just enough water to sufficiently oxygenate the eggs without drowning them.  They need the sea floor to gently rise into breeding beaches, allowing easy access. While breeding, crabs have to eat small bivalves, which they find in abundance in the bay’s extensive intertidal and subtidal flats.

The most important aspect of the bay is its quickly warming waters in the spring. On Delaware Bay, horseshoe crabs don’t breed until waters reach 59 degrees. You won’t see this temperature on the Atlantic Coast until June. Not so on Delaware Bay!  Although the bay has deeper water, mostly in sloughs that snake under the surface out to its mouth at Cape May, most of the water is relatively shallow — usually less than 18 feet. That may sound deep, but keep in mind the Chesapeake has 100 feet water for most of its length and deeper water throughout. The shallow water of Delaware Bay allows it to heat up soon after the air temperature rises.

 

Unfortunately, it also cools down quickly and because of this the crab spawn has stopped. The bay’s water temperature went up dramatically in late March and April, so much so that we worried it might reach the critical 59 degree threshold in April long before the birds arrived in May. But then the warm weather stopped and the bay temperature dipped than rose, several times in fact. By early May, it had gotten just above the threshold, heating up to about 61 degrees at the Cape Henlopen marine buoy. We hoped for the best. Crabs started to breed in good numbers on a few beaches, like Reeds Beach, but were thin elsewhere. We had about 20,000 shorebird relying on the spawn and the eggs that were brought to the surface.

Than the bay cooled down again. A nasty western wind and cold front enveloped our area over the weekend and the cool weather followed. By Monday, the temperature went down again and the crab spawn stopped. This is bad.

 

When the spawn stopped the birds hovered up the remaining eggs in a few days. Then they started wandering to find eggs in odd places, under houses, along bulkheads. Some even went to areas like the oyster aquaculture racks to find eggs to the delight of the people trying to expand aquaculture. But what they saw was desperation.

Worse the Black Back and Herring Gull that feed on eggs and overturned crabs couldn’t find eggs and started eating shorebirds. By the end of Thursday (May 19) we found 8 dead red knots. These gulls can swallow small sanderling and semipalmated sandpipers like gum drops, so we really don’t know how many shorebirds died.

Relief might be in sight though. Thursday, Friday and today will be warmer. The bay’s temperature is back up over 60 degrees. Thursday night we had a fairly good spawn. Hopefully we will be back in business soon.

 

Learn More:

• Conserve Wildlife Foundation’s Delaware Bay Shorebird Project
• Conserve Wildlife Foundation’s online field guide: Red Knot

 

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

A Series of Updates on Year 20 of the Delaware Bay Shorebird Project

By: Dr. Larry Niles, LJ Niles Associates LLC

Our team trapped over 500 shorebirds over the weekend including several hundred red knots in two catches on May 12^th and 14^th! Most of the caught birds, knots, ruddy turnstones and sanderlings arrived in good condition, which is always a relief at this early stage in the season. Ruddy turnstones returned in better-than-average condition, weighing in at 5 grams higher than normal arrival weights.

The condition on arrival is an important focus of the project. In some years, knots struggled to get to the bay, coming in at average weights of 105 grams, 15 grams lighter than this year. One poor soul practically fell onto the beach with only 84 grams of weight, dangerously burning muscle to get here.

 

To really understand it best you must put yourself in the birds’ shoes (in a matter of speaking). We can do this because we have been attaching small tracking devices called geolocators on knots and turnstones for the last 5 years. Geolocators must be recovered to download the data, and we did this with a knot banded with the inscribed flag TVV in 2015. The map of that bird’s heroic journey can be seen below.

Follow TVV’S path from Delaware Bay to its Arctic breeding area, then down to its Chilean wintering area, then back to Delaware Bay. It spent less than one month in the Arctic but over 6 months in its Tierra Del Fuego winter quarters. The rest of the time was spent flying or resting between flights. It’s flight from Southern Brazil to Delaware Bay was truly awe inspiring!

 

Imagine you are TVV and about to fly from balmy Brazil to Delaware Bay, 5,000 miles away. Most birds will leave near nightfall, when the weather is settled and usually when there tends to be a favorable wind. Once aloft you have no idea of the conditions you will face for the next 6 days. Some birds have an easy time of it, some get caught in opposing winds, others get blown off course and must struggle to return. This is the reason for the varying weights on arrival.

So what did the birds find when they arrived this year? So far, the horseshoe crab spawn has gone well. It started early in the month, so that by the time birds like TVV arrived, they found a nice concentration of eggs for the taking on Delaware Bay beaches. At first, the birds poured into the bay.  Last Thursday May 10^th, we had about 1,000 knots on the New Jersey side of the bay. By Saturday, the number has grown to 8,000 knots – and our two catches proved they were gaining weight at a good clip.

 

All that changed on Sunday when a complicated cold front hit the bayshore. For two days we have had strong winds from the west, creating breaking waves on much of the New Jersey bayshore. The crab stopped spawning in most places. The winds blow as I write this blog and is certainly holding up birds from arriving, some may have stopped migrating others are fighting this merciless 30 mph wind.

In our next post, learn how the winds affected the birds over the last few days.

 

Learn More:

• Conserve Wildlife Foundation’s Delaware Bay Shorebird Project
• Conserve Wildlife Foundation’s online field guide: Red Knot

 

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

Delaware Bay Shorebird Project Begins 20th Season

By: Dr. Larry Niles, LJ Niles Associates LLC

We begin the 20th year of the Delaware Bay Shorebird Project this year with many of the same team members that helped start the project in 1997. That’s 20 years of studying one of the most intellectually challenging and endlessly fascinating species of wildlife in the world. Few have had the good fortune to do so.

Unfortunately, we do not start this year with the same shorebird population. In the last twenty years, the Delaware Bay stopover fell precipitously from its once lofty perch as one of the top three stopovers in the world. Where once we counted over 1.5 million shorebirds, we now see less than 400,000, a sweet number but far less than the bay’s heyday. Red knot numbers have crashed from over 90,000 to a low of only 13,000. Ruddy Turnstones, the virtual working man of shorebirds, fell from 135,000 to just over 16,000. In this time, many intrepid shorebirds came to the bay to find succor provided by a once endless bounty of horseshoe crab eggs only to find empty beaches and no way back to their Arctic home.

 

Much of this was caused by short-sighted decisions made by the commercial fishing industry in the 1990’s, which decided to spend this bay’s natural (and publicly owned) wealth of horseshoe crabs. They needed bait and relentlessly pursued the crabs. Horseshoe crab populations fell to a quarter of their historic number and may have been driven to extinction without the work of the bay’s conservationists who fought bravely and with determination to stop them. Atlantic sturgeon, weakfish, herring, eels, and many of the bay’s once abundant fisheries weren’t so lucky.

Now a new industry, the oyster aquaculture industry, wants to consume another public natural resource, the bay’s intertidal flats. Cultivating oysters on metal racks placed on the bay’s extensive tidal flats is cheap and easy when you can use public trust lands. The expansion got a vital assist from the state agencies who side lined crucial environmental reviews to determine impact to species like the red knot, and required no public hearing, comment period or the involvement of any shorebird experts. This could have been corrected when the red knot was federally listed.

Unfortunately, the red knot’s federal listing has not helped in this controversial expansion of aquaculture. Instead, it proposed growers should be compensated for economic losses caused by the listing, and allowed the controversial expansion despite the obvious impacts to birds and crabs. Such decisions speak to Desperate Environmentalism, a term coined by Yale School of Forestry’s Joshua Galperin, describing the increasingly fraught position of conservationists who feel they must play ball with politically powerful industries or lose all. This desperate conservation could have been avoided if growers and conservationists worked together to expand aquaculture without significant impacts — because after all everybody loves oysters!

But this dark cloud cannot diminish the progress made by our team and groups like American Littoral Society and Conserve Wildlife Foundation of New Jersey. Just one example is the successful effort to restore horseshoe habitat on 2.7 miles of Delaware Bay horseshoe crab breeding habitat. The effort, funded by National Fish and Wildlife Foundation and the U.S. Fish and Wildlife Service, overcame the damage caused by Hurricane Sandy and prevented what could have been another shorebird disaster. This work has blossomed over the last four years into a network of activities that provides new hope for a long term protection of the bay. This conservation is not desperate but inspirational for hundreds biologists, land managers and volunteers.

So our 20^th year is much like our first year, a group of conservation-minded shorebird scientists and volunteers gathering to help these poor birds find a way to make it home.  As with most conservation stories in this time, it’s a David and Goliath story that hopefully has the same result.

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

CWF is Celebrating International Migratory Bird Day all Week Long

by Lindsay McNamara, Communications Manager

CWF’s blog on the red knot is the third in a series of five to be posted this week in celebration of International Migratory Bird Day (IMBD). IMBD 2016 is Saturday, May 14. This #birdyear, we are honoring 100 years of the Migratory Bird Treaty. This landmark treat has protected nearly all migratory bird species in the U.S. and Canada for the last century.

The iconic red knots have returned to New Jersey! These famous, mid-sized shorebirds are state endangered and now federally threatened — the first bird ever listed under the Endangered Species Act with climate change cited as a “primary threat.”

 

Red knots are only 10 inches long but are among the world’s most extreme long distance flyers — traveling vast distances — some over 18,000 miles in the course of their annual migration from Tierra del Fuego, Argentina all the way up to the Canadian Arctic (and back again). During their trip, the red knots make a vital stop at New Jersey’s Delaware Bay.

Each spring in Delaware Bay, throughout the month of May, the largest concentration of horseshoe crabs in the world comes onshore to spawn. At the same time, tens of thousands of shorebirds arrive at the Bay, thin and spent from what has been a non-stop, four-day flight from South America. They are en route on a remarkable round-trip journey from southern wintering grounds to Arctic breeding territory, and Delaware Bay is their most critical stopover on this 8,000-mile trip. The shorebirds need to quickly double their weight to complete their migration north and breed successfully. To refuel at such capacities and in only a ten-day window, high-energy horseshoe crab eggs provide essential nourishment. In recent years, countless horseshoe crab eggs have been lost because of the devastating storms that swept away the beaches they depend on.

 

In the wake of Hurricane Sandy, Conserve Wildlife Foundation and American Littoral Society worked with the U.S. Fish and Wildlife Service, the New Jersey Division of Fish and Wildlife and the New Jersey Recovery Fund to remove 8,000 tons of debris and added 45,000 tons of sand to the beaches just before the annual spring arrival of the red knot in 2013. Additional work after 2012 restored another mile of shoreline, including two new beaches of poor quality even before Sandy. To date, the groups have placed over 85,000 cubic yards of sand and restored seven beaches along New Jersey’s Delaware Bayshore.

 

To restore one of the beaches, Thompsons Beach, our team removed debris from the area, removed rubble from the road leading to the beach, and placed over 40,000 cubic yards of sand onto the beach. We were delighted to learn that in the spring of 2015, Thompsons Beach had the highest abundance of horseshoe crab egg clusters out of all the beaches that our team monitors on Delaware Bay.

But since the early 1990s, there have been major declines in both the number of adult horseshoe crabs and their eggs. The cause is an exploding crab harvest that grew from only tens of thousands in 1990 to over 2 million in 1996. With the decline of their critical food source, shorebird numbers also plummeted — the Delaware Bay shorebird populations remain around 26% of its historic population size. Over 25,500 red knots were seen in 2015 versus over 90,000 in 1989.

 

Conserve Wildlife Foundation and the Endangered and Nongame Species Program (ENSP) of the New Jersey Department of Environmental Protection’s Division of Fish & Wildlife have partnered for 20 years, working to conduct research on Delaware Bay shorebirds in order to prevent further decline. Each year, CWF’s Larry Niles and ENSP’s Amanda Dey lead a team of shorebird experts from around the world – from countries as far as Argentina and New Zealand – to conduct research on shorebirds during their stopover. These experts also follow shorebirds to other locations along their migration, including South America and the Arctic. With scientific research and concerted conservation efforts, our hopes are that someday Delaware Bay’s skies will be once again filled with shorebirds.

Last year, nearly every red knot left the bay in good condition, with over 77% reaching weights exceeding 180 grams, the threshold weight required for a successful flight to the Arctic breeding areas. The improvement in the number of red knots reaching 180 grams is a milestone for our shorebird project. The birds left in the best condition recorded since 1998, just as horseshoe crabs were being overharvested. This good news must be tempered by the continued low numbers of birds and horseshoe crabs. We report no improvement in horseshoe crab numbers, so the improvement in the number of red knots making weight is likely a consequence of the restoration of horseshoe crab habitat on Delaware Bay beaches.

 

Because shorebirds don’t only spend their time in Delaware Bay, shorebird scientists must study them throughout the Atlantic Flyway to get the best understanding of their unique ecology. This year, shorebird project team was awarded a 2-year grant to create detailed shorebird habitat maps in the states of Maranhão and Pará, Brazil. This project will set the foundation for conservation planning and action for decades to come at a shorebird wintering site of hemispheric importance that has received little conservation and research attention with regard to shorebirds thus far.

 

Over the last 6 years, CWF also has partnered with the USFWS Monomoy Refuge to develop a better understanding of migratory shorebird use on Cape Cod and at the Refuge. Cape Cod, like Stone Harbor and Brigantine, New Jersey, is an important southbound stopover for red knots. At each location, red knots come from their Arctic breeding areas and either build up weight for a flight to South America, or remain to molt and replace vital primary feathers before moving onto shorter distance wintering areas in Florida and Cuba.

Another important piece of CWF’s shorebird research has been the attachment and recovery of geolocators, small devices that track movements through one to two years of battery life. The migratory tracks from recovered geolocators have greatly expanded our understanding of red knot migratory behavior. In CWF’s last two years of research, we focused on capturing juveniles, which move through the Cape in early September. Red knot juvenile #254 was a recapture two years after release on Delaware Bay. It first left Cape Cod and wintered in North Carolina. In their first year, juvenile red knots don’t go to the Arctic to breed and so #254 flew back to Cape Cod to summer. The following fall, it flew to Cuba to winter, then to North Carolina, then to the Arctic. This was the first known track of a juvenile red knot and one of only a few of any avian species! CWF is continuing our geolocator project this year, so follow along on our blog and social media channels to receive updates on cutting-edge red knot research!

 

Learn More:

• Conserve Wildlife Foundation’s Delaware Bay Shorebird Project
• Conserve Wildlife Foundation’s online field guide: Red Knot

 

Lindsay McNamara is the Communications Manager for Conserve Wildlife Foundation of New Jersey.

The Birds are Back – Red Knots Arrive Along the Bayshore

by David Wheeler, Executive Director

The 2016 mass shorebird migration is officially underway, with the thrilling spectacle of over 1,100 red knots spotted today at North Reeds Beach in Cape May County, New Jersey. A host of other shorebirds, including ruddy turnstones, dunlins, semipalmated sandpipers, and sanderlings, accompanied the red knots at this Delaware Bay hotspot.

 

The famished flocks fed on horseshoe crab eggs, while much larger laughing gulls congregated along the shoreline and a few crabs used the incoming waves to flip themselves over and return to the bay.

Researchers began seeing a large number of shorebirds arriving over the weekend, and today’s sightings are high for such an early date. A number of the red knots wear leg bands, with a few indicating departure points as far south as Argentina and Chile. Such lengthy migrations for those individual birds only add to the intrigue of their early-season arrivals in New Jersey.

 

Some red knots fly over 18,000 miles each year in their migrations from southern South America to the Canadian Arctic, with Delaware Bay serving as an irreplaceable stopover.

Yet these migratory shorebirds have suffered a sharp decline over the past few decades, with red knots dropping by around 75%. The U.S. Fish and Wildlife Service designated the red knot as a federally protected threatened species under the Endangered Species Act in December 2014.

 

A team of international researchers and trained volunteers, led by Dr. Larry Niles, Conserve Wildlife Foundation, and the State Endangered and Nongame Species Program will spend the next month surveying and studying the at-risk shorebirds during their stay in New Jersey.