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Posts Tagged ‘Bird Banding’

Red Knots “Vote with their Wings”

Friday, May 29th, 2015
An Update from the 2015 Delaware Bay Shorebird Project Team

By: Dr. Larry Niles, LJ Niles Associates LLC

Clive Minton is fond of saying, “the knots vote with their wings” as a way of saying knots concentrate in the best places for knots. Of course it’s true, animals move to the habitats they find most suitable, nature leaves little room for anything but. Sometimes however, animals use a habitat only because they have little choice — in other words, they are making the best of a bad situation. The job of a good wildlife biologist is to understand the difference. Unfortunately, it’s often not obvious.

Red Knot Photo by: Jan van der Kam

Red Knot Photo by: Jan van der Kam

 

In all the places studied by this author — Tierra del Fuego, the Arctic, and many places in between — knots distinguish themselves as highly selective habitat specialists. There are many practical reasons for this: usually knots occur in flocks and thus require more space than many other species. More importantly, as they put on weight for their incredibly long-distance flights, they often push the limit of safe wing-loading (body weight to wing area). This makes them vulnerable to predators, both real and imagined. They need more flying space, more space for advance warning of a predator’s presence. They demand special roost habitats as well, especially night roosts that are free from disturbance and have good sight distances. Altogether they need more.

Red knots roost on a sandy spit on Egg Island, one of the largest contigous area of marsh in the mid Atlantic.   Half of the bay's shorebird population roost on Egg Island and than feed on the various beaches around Fortescue.

Red knots roost on a sandy spit on Egg Island, one of the largest contigous area of marsh in the mid Atlantic. Half of the bay’s shorebird population roost on Egg Island and then feed on the various beaches around Fortescue.

 

In Delaware Bay, they need all this, but above all they need good horseshoe crab egg densities. In the mid 2000’s when shorebird numbers were high, the demand for those eggs exceeded the production from the rapidly diminishing crab population. Knots wandered the bay like homeless refugees. Competition for eggs drew tens of thousands of birds to places unused by knots in healthier times.

Mispillion Harbor

Mispillion Harbor

 

Mispillion Harbor, Delaware, for example, in some years supported much of the knot population in the Bay because it acts like a funnel-trap for crabs. Crabs wandered into the harbor through long stone jetties finding themselves in crab breeding heaven, sandy shoals in a closed space, free from wind-generated waves that normally leave them upside down. The egg-laying frenzy caused eggs to reach epic densities, thus preparing many shorebirds for their onward journey to the Arctic. Tens of thousands of shorebird packed into Mispillion Harbor in densities so high that one could smell ammonia off-gassing from the amount of bird waste.

 

But for knots, Mispillion left a lot to be desired. The same jetties that protect the inner harbor from wind-driven waves also provide low-flying raptors the cover to pounce on flocks before they can easily react. Fat birds make easy prey for peregrine falcons, who themselves struggle to keep up with the insatiable hunger of rapidly growing chicks.

Photo by:  Jan van der Kam

Photo by: Jan van der Kam

 

But even as shorebird numbers fell in response to the reduced crab numbers, egg densities improved in other places. Knots reassessed their choices and voted with their wings.

 

This is why this year’s high count of red knots on the New Jersey side of the Bay are so important.  Two days ago, Mark Peck, Joe Smith and I flew the entire Bay to count knots, ruddy turnstones and sanderlings. We counted over 24,000 knots, with 21,000 of these using the beaches managed by the many groups that take part in shorebird management on the New Jersey shore of Delaware Bay.

 

I am not saying this is a competition between two states — I’m saying the numbers serve as assurance that all our hard work is paying off. It’s a confirmation that the beach restoration projects, the Shorebird Stewards project, the reTURN the Favor crab rescue project, and more are bearing fruit. These coordinated strategies are led by Conserve Wildlife Foundation of New Jersey, American Littoral Society, Manomet Center for Conservation Sciences,  New Jersey Audubon Society, the Wetlands Institute, Citizens United to Protect the Maurice River, The Nature Conservancy, as well as Downe Township, Maurice River Township, Middle Township and the Division of Fish and Wildlife, New Jersey Department of Environmental Protection. This work is funded by the US Department of Interior, Fish and Wildlife Service, the National Fish and Wildlife Foundation and the Willliam Penn Foundation. Good work all!

Jim May protect Cook Beach as part of  Conserve Wildlife Foundation of NJ's Shorebird Stewardship Project.  Each year the Division of Fish and Wildlife designates beaches important to shorebirds and protects them from disturbance.  The shorebird stewards alert Conservation Officers if people refuse to comply.  But most of thier job is helping people understand the shorebird migration and the needs of shorebirds and crabs

Jim May protects Cook Beach as part of Conserve Wildlife Foundation of New Jersey’s Shorebird Stewards project. Each year, the Division of Fish and Wildlife designates beaches that are most important to shorebirds and protects them from disturbance. The shorebird stewards alert Conservation Officers if people refuse to comply, but most of their job is helping people understand the shorebird migration and the needs of shorebirds and crabs.

We now near the end of the stopover season at Delaware Bay. Three days of southerly winds are proving irresistible for many birds. Nearly two-thirds have left and the rest will be gone in a few days. Thanks to the people who love birds and the residents of the Bay, they leave well-prepared for the next stage of their challenging and inspiring lives.

knots in the air

Learn more:

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

 

Delaware Bay Shell-a-Bration Captured on Video

Wednesday, May 27th, 2015
South Reeds Beach Oyster Reef Event Filmed by Local Delaware Bay Producer

By: Lindsay McNamara, Communications Manager

A record number of Red Knots were counted on New Jersey’s Delaware Bay this year, in part because of innovative restoration projects like our South Reeds Beach oyster reef.

 

Over 130 volunteers and veterans worked alongside Conserve Wildlife Foundation and American Littoral Society to establish a near-shore whelk shell bar at South Reeds Beach in Cape May Court House on the Delaware Bayshore in early April.

 

Shorebirds, like the federally listed Red Knot, depend on an uninterrupted supply of horseshoe crab eggs when they stopover in Delaware Bay during their migration. In recent years, countless horseshoe crab eggs have been lost because of the devastating storms that swept away the beaches they depend on.

 

The oyster reef was built to prevent sand loss from wind-driven waves. The approximately 200-foot project will test whether the reef bars help reduce beach erosion and create calmer water for spawning horseshoe crabs.

 

Learn more about the project and our “Shell-a-Bration” event in the video above produced by Kathleen Poliski of K. Productions, LLC!

 

The South Reeds Beach Oyster Reef is one of the many projects that American Littoral Society and Conserve Wildlife Foundation are working on to restore the ecology and economy of the Delaware Bayshore, thanks to generous funding by the National Fish and Wildlife Foundation. To learn more, visit RestoreNJBayshore.org.

 

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

13,000 Red Knots on New Jersey’s Delaware Bay

Thursday, May 21st, 2015
An Update on the 2015 Delaware Bay Shorebird Project

By: Dr. Larry Niles, LJ Niles Associates LLC

We had about 13,000 knots on the New Jersey side of the Delaware Bay (an additional reported 2,000 on the Delaware side of the Bay). Yesterday, we suffered strong NW winds in excess of 20 kts and the birds virtually disappeared. Our daily survey turned up about 6,000 knots, the rest we suspect, finding refuge in Egg Island and Goshen Marshes or with a flyover to Delaware.

 

We will know where they went today. The team will comb the Bayshore for shorebirds with a coordinated ground, boat and aerial survey. The birds gain weight in good time and we expect the first Arctic lift-offs by the 26th. At the current rate, most of the Bay’s population will be off to the Arctic by the 30th.

 

Above is a clip from a new video about knots and our work by Mitch Smith, a longtime supporter of the team and head of the Mitch Smith Media.

 

Learn more:

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

 

2015 Horseshoe Crab Spawn and Shorebird Migration on Delaware Bay

Wednesday, May 20th, 2015
An Update on This Season’s Horseshoe Crab Spawn and Shorebird Migration, Ten Days In

By: Dr. Larry Niles, LJ Niles Associates LLC

Thousands of shorebirds now fill Delaware Bay’s beaches and marshes in a determined effort to regain lost reserves with free-for-the-taking fatty eggs of the horseshoe crab. The crab spawn began ten days ago and has gained momentum over the last week as the volume of eggs grows like a well-funded savings account. The eggs surface as each new female crab digs up egg clusters laid by other crabs or as wind-driven waves pound the always-fluid sandy beaches. At least 8,000 red knots slowly get fat on the eggs scattered on New Jersey’s Delaware Bay beaches.

Eggs on Beach

Eggs on Beach

Both crabs and birds are the beneficiaries of the increasing number of beaches that are highly suitable for egg-laying. In October, 2012, Hurricane Sandy ravaged two-thirds of New Jersey’s best crab-spawning beaches, its strong westerly winds lifting sand and spreading it far from the sea’s edge. Left behind was a jagged sod bank, completely unsuitable for horseshoe crab breeding. The mucky sod starves eggs of oxygen or gasses them with hydrogen sulfide, the by-product of decaying mud.

 

The American Littoral Society, Conserve Wildlife Foundation of New Jersey, the U.S. Fish and Wildlife Service and the National Fish and Wildlife Foundation came to the rescue, restoring many of these beaches to a condition superior to that before Sandy. The restoration team even repaired damages that predated Sandy — beaches with tons of rubble that entrapped crabs in nasty concrete, killing them by the thousands. Now beaches like Thompson’s Beach and Fortescue Beach join the growing number of delicate sandy strands that provide excellent spawning habitat.

Thompsons Beach Before and After

Thompson’s Beach Before and After Restoration

This week, eggs can be found in many places on the New Jersey side of Delaware Bay, and the birds have the freedom to move to those that best suit them. Earlier this month, strong northwest winds drove red knots from the Reeds Beach area to other, more northerly, beaches that saw good crab spawning — beaches that also provide shelter from the winds. Now that the wind and sea have calmed, the birds have returned to the Reeds Beach area, less than 20 miles away, and have resumed gorging on the plentiful eggs that built up in their absence.

Early Morning Shorebirds on Delaware Bay

Early Morning Shorebirds on Delaware Bay

If one were to look for any cloud on the Delaware Bay shorebird horizon, it would lie in the lack of any evidence of horseshoe crab recovery. The current, reduced, population of crabs spawned eggs in great numbers early this May because of a spike in the water temperature, a consequence of unusually warm weather.  So far the promise of this early spawn is holding, and crabs continue to spawn in good numbers. But will it hold until the end of May?

Crabs in Slew

Crabs in Slew

If not, the readers of this blog will witness the outcome. The graph below, developed by long-time team-member Dick Veitch tells the story of a past egg failure. In the early 2000’s, although the population of shorebirds had not yet declined to its current number, the crab population had already fallen to its current number, crushed by the onslaught of a poorly regulated fishing industry.  In those years, all the horseshoe crabs that could spawn had finished by the third week of May and egg densities on the bay plummeted. The birds crammed into the few beaches with eggs like Mispillion Harbor, Delaware, so densely that the beach reeked of off-gassing urinary ammonia.

 

But the number of eggs there was not sufficient to feed the still-large shorebird populations and birds failed to reach a weight – about 180g for red knots — suitable for their journey to the Arctic and subsequent breeding. Where once 80% reached the “good” weight, only 5% did in 2003 (see the second graph).

Percentage of Red Knots Reaching 180 Grams

Percentage of Red Knots Reaching 180 Grams

The percentage has improved thankfully, but only because the number of shorebirds have fallen over the last 10 years, bringing a balance of sorts. Hopefully, with the new beaches, the new protection afforded by the red knot listing and the growing number of volunteers taking part in conservation of the crab and birds, this kind of disaster is behind us.

We shall see.

 

Learn more:

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

2015 Delaware Bay Shorebird Project Begins!

Tuesday, May 12th, 2015
Another Season of the Delaware Bay Shorebird Project Underway

By: Dr. Larry Niles, LJ Niles Associates LLC

Our 2015 Delaware Bay Shorebird Project began on one of the hottest early-May weekends in memory. Clive Minton, an English-expatriate Australian, and I began the project with an early morning survey of each bay beach – Reeds, Cooks, Kimbles, Pierces, Rutgers, Norburys, Villas – dripping sweat and swatting biting gnats as though it was early June, not early May. The sudden burst of summer weather warmed the bay waters, triggering our first horseshoe crab spawn providing sufficient eggs for newly arriving birds.

Delaware Bay Team 2015

 

The birds, on the other hand, followed a more normal schedule. We counted only 400 knots, a smaller number of ruddy turnstones and, surprisingly, no sanderlings. We know the birds are en route; Pat Leary in Florida and Fletcher Smith in Georgia report good numbers of knots, but the birds appear stuck because of the unsettled weather and the rare occurrence of a tropical storm making landfall in North Carolina over the weekend. Soon enough they will come.

Red Knot Photo by: Pat O'Leary

Red Knot Photo by: Pat O’Leary

The warm weather and the abundant crab spawn bode well for the birds – we want the early bird to gets eggs.  But they point to one of the many difficulties facing the red knot and other shorebirds. Will the insidious effects of climate change unravel this elegant machine that provides horseshoe crabs eggs just at the time Arctic-nesting shorebird need them to fly on to their breeding areas?

Horseshoe Crab Eggs

Horseshoe Crab Eggs

Horseshoe Crab Eggs

Horseshoe Crabs Spawning

Our project is 19 years old and so provides a perspective virtually unique among wildlife projects. A long-running project of this kind has many advantages, not the least of which is the human family that has formed around our love of birds. We have nearly the same core team in 2015 as we did in 1997, losing and gaining a few team members as time marches on, but always maintaining an esprit de corp, a common purpose, a lasting bond. The shorebirds, the crabs and the many people who love the Delaware Bay owe a debt of gratitude to this team of intrepid researchers.

Photo by: Christophe Buidin

Photo by: Christophe Buidin

The project’s longevity also creates a perspective rare in the world of bird study. Over 19 years we have seen the collapse of the horseshoe crabs; the dramatic free fall of the red knot that resulted this year in a federal listing as Threatened; the rise of irresponsible commercial exploitation of the natural wealth of the bay; a devastating hurricane and more. And yet each year the birds arrive, the crabs spawn and our team coalesces from every corner of the world. Despite the problems and all the concern, the system persists.

 

But how long will the system persist?

 

The challenges faced by the birds grow every year. They cling to this amazing migratory bird like barnacles on a wooden boat.  Crabs have not recovered from the devastating overharvest of 15 years ago. The international drug cartels still drain the blood of crabs for the valuable chemical lysate without any responsible management. All the while shorebirds, the red knot in particular, face growing threats from climate change: more frequent storms, destroyed coastal habitat, rapidly-changing arctic tundra habitats.

Lysate Industry

Herein lies the value of a long-term study. This season’s unprecedented early spawn and warm weather could be good or bad.  Either way, by season’s end, the team’s dedication, skill, and plain hard work means we will know what happened and what it means compared to 18 other years.

Early Red Knots

Early Red Knots on Baycove Beach on Delaware Bay

 

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