Conserve Wildlife Blog

Posts Tagged ‘migration’

In Dangerous Territory on the Delaware Bay

Wednesday, May 24th, 2017

By Dr. Larry Niles, LJ Niles Associates, LLC

Four days ago, the shorebirds of Delaware Bay could look forward to a bright future. But in the last week their chances for survival and good production have diminished. In fact, they are as dismal as the cold drizzle pockmarking the murky water in front of our house on Reeds Beach.

The following two graphs tell the story. We captured red knots on May 12 and 16 that showed a normal, although not spectacular progression. Then we made a catch of knots on the 19th and again today on the 23rd, and in total they gained only 2 grams of fat per day. With an average weight of 144 grams at this late date and only 7 days to go before they must leave for the Arctic, their future looks bleak. If current conditions hold, the knots will suffer their worst year in 14 years. Turnstones fared no better gaining less than a gram per day on average.

The graph plots all the average weights of all the catches of red knot our team has made since 1997. The average weight of our catch on May 23 suggests trouble is brewing for these birds.

 

The graph plots all the average weights of all the catches of ruddy turnstones our team has made since 1997. The average weight of our catch on May 22 suggest trouble for both species.

So why this dismal report? Several factors are at work that were covered in my last post. The water temperature of the bay has only just exceeded the threshold for horseshoe crabs to start breeding in earnest. But the nights are cold and the water temperature remains cold. Last night was the first good crab spawn since the birds arrived and it was lackluster. Although there is some spawning in the creek mouth shoals and the lower beaches near Norburys Landing and Villas, our most productive beaches remain nearly devoid of crabs and crab eggs.

The second problem is still a mystery. At this stage only about half of the red knots have found their way into the bay. Weather patterns in the southern US could have been blocking migration for the last 5 days because adverse winds, poor visibility and rain impedes birds progress and could stop northward movement. The conditions have finally let up, so it possible a new cohort of birds might arrive any day. If so they will face a true food fight with many birds already here and desperate for eggs.

Laughing Gulls, Red Knots, Ruddy Turnstones, Sanderlings and Semipalmated Sandpipers struggle to find horseshoe crab eggs on the shoals of South Reeds Creek. Eggs are scarce because cool water temperatures prevent crab spawning.

However, it may not be the adverse weather but choice that is keeping the population down. Today we learned of a red knot banded on May 16 this year by our counterparts in Delaware that was resighted in Cape Cod by Mark Faherty, the senior scientist for Massachusetts Audubon in Cape Cod. In other words, red knots and other shorebirds are coming to the bay finding too little food or too much competition for the food now available and choose to move on. This is very possible for the short distance migrants because they arrive earlier and have less weight to gain before leaving for the Arctic. Knots wintering in Tierra del Fuego, arrive later and in much worse condition, often times lose muscle mass to get here. They cannot recover that loss and still gain an extra 80 grams on their normal diet of mussels and clams.

We tried to test this second possibility today (May 23) after our red knot catch this morning. Humphrey Sitters, Amanda Dey and I surveyed the intertidal mud flats of the Atlantic Coast from Cape May to Stone Harbor looking closely at the mussel beds. We know that every year red knots, especially short distance birds, use mussels and to some extent clams, rather than come to the bay and feast on horseshoe crab eggs – simply because they can. We found 1700 knots, so it possible even more are spread out further up and down the coast.

In the end, it may turn out to be both explanations. The short distance knots are using the Atlantic Coast and the long-distance birds have yet to arrive. One should remember that the knot is federally listed in both Canada and the US primarily because of the dramatic declines in the long-distance winters. There is still a small window for a successful outcome. The next few days will tell the full story.

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


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New Jersey’s Key Role in the Monarch Migration

Tuesday, October 4th, 2016
The Garden State annually hosts swarms of southbound Monarch Butterflies

By: Kendall Miller, Project Coordinator

Monarch butterfly refueling in Cape May as it prepares for fall migration to Mexico. Photo courtesy of Lindsey Brendel.

Monarch butterfly refueling in Cape May as it prepares for fall migration to Mexico. Photo courtesy of Lindsey Brendel.

Monarch has been a conservation buzz-word for the past decade when data revealed that the population had appeared to be on the decline. Then in 2013, the population of wintering monarch butterflies in Mexico reached an all-time low that jolted scientists, environmentalists, and enthusiasts across the nation.

Monarch abundance in wintering grounds is measured as area in hectares. They roost in large colonies in the Transvolcanic Mountains in Mexico. The 2013-2014 overwintering population experienced the lowest recorded area to date, at 0.67 ha. From MonarchWatch.org.

Monarch abundance in wintering grounds is measured as area in hectares. They roost in large colonies in the Transvolcanic Mountains in Mexico. The 2013-2014 overwintering population experienced the lowest recorded area to date, at 0.67 ha. From MonarchWatch.org.

This marvelous and iconic lepidopteran is found throughout the continental United States. Its 3,000 mile long migration is an amazing natural phenomenon. The news of population declines in Mexican wintering sites inflamed concern and incited action. Many groups have since created partnerships, implemented programs, and conducted research to understand more about this widely known yet still mysterious insect.

The location of wintering monarchs was a complete mystery until 1975 when the remote wintering sites were discovered in transvolcanic mountain ranges in Mexico. Much is still to be discovered about the migration pathways even within the United States, and doing so will answer questions which will inform conservation and management of this species which faces multiple threats during every aspect of its expansive journey.

Glider pilots have observed monarch butterflies at an altitude of 1200 meters (Gibo 1981).  Migratory flights at these altitudes can allow insects to disperse against wind directions found at lower altitudes.


But first, a little bit about biology and the annual life cycle

The monarch’s annual lifecycle is a really marvelous and multifaceted journey – it can be thought of as a multigenerational relay race.

From the Xerces Society. Map depicts the known general migration routes of monarch butterflies.

From the Xerces Society. Map depicts the known general migration routes of monarch butterflies.

Monarch butterflies, just like other lepidopterans, metamorphosis from caterpillar to butterfly. The big thing that sets them apart is the migration they make annually. (Although there are many other species of moths and butterflies, and other insects as well that migrate – the monarch is arguably the most well recognized example http://texasento.net/migration.htm).

Temporal cues and an innate determination drive these ambitions fliers to travel as far north as the Canadian border. In the search for milkweed and favorable temperatures – possibly to avoid disease pressures – monarchs fly north to reproduce and recolonize across North America each year.

They leave overwintering grounds in Mexico in early spring. Along their route the monarchs will mate and reproduce. Their lives are lived within a short couple weeks, and their offspring will continue the migration northwards in search of food and milkweed.

When the seasons shift in late summer and early fall, the last generation of monarchs will begin a southbound journey, instinctively traveling to wintering sites in Mexico (there are a few populations that overwinter in California and Florida – but the large majority are thought to return to Mexico). This generation will be responsible for making the longest trek of the migration to wintering grounds. These monarchs enter reproductive diapause – the state where the body will temporarily pause reproduction – until the following spring. These monarchs will spend the winter roosting in trees in Mexico until spring when they will take up the first leg of the relay north.

This last generation from the previous year now makes up the first generation of the present year – and will pass the baton on to their offspring as the cycle starts anew.


The role of the Garden State

So what part does New Jersey play in the grand scheme of this massive population?

The Atlantic coast migration was once characterized as “aberrant”, a fluke of sorts – the result of southbound monarchs being blown off course. Research and monitoring conducted in Cape May and published by Walton and Brower (1996) in The Journal of the Lepidopterist’s Society have supported the hypothesis that a migration along the Atlantic coast is part of the monarch’s normal fall migration.

What does a monarch have in common with a hawk?
Walton and Brower (1996) have proposed the idea that monarch butterflies could display similar flight patterns to that of migrating hawks. Utilizing an elliptical flight path during the fall south-bound migration, the model suggests that these birds take advantage of prevailing winds by first traveling east and then west, thus providing a quicker and more energetically-efficient route. Could monarch do the same?

New Jersey – Southern New Jersey and Cape May in particular – is historically recognized as a concentration area for southbound monarchs during the fall migration to wintering grounds. Hamilton (1885) [expressed his wonder of the] characterized the September 1885 monarch migration at Brigantine, New Jersey as “almost past belief … millions is but feebly expressive … miles of them is no exaggeration.” Reports of trees “more orange than green” is no exaggeration, as monarchs congregate en masse in prime roosting spots to warm and rest.

But why is this important? The monarchs migrating through Cape May seem to be representative of the entire North Eastern population – and therefore it offers the opportunity to collect quantitative data on populations in addition to other annual counts. The fourth of July counts focus on quantitatively monitoring the Northeastern population of monarchs as they arrive in the spring and summer. Therefore this data can be used to analyze population trends.


What part can New Jersey residents play?

Monarchs are traveling across New Jersey May through October. There are plenty of simple ways you can help protect this iconic species.

  • Plant native species of flowering plants – monarchs and other insects (like bees) rely on a healthy diversity of nectar sources. Planting a wildflower garden is a quaint, ecological-friendly way to create habitat, and not to mention, make less work watering and money spent purchasing plants. Check out the Native Plant Society or Jersey Friendly Yards to get started. http://npsnj.org/ http://www.jerseyyards.org/
  • Share this article, talk about environmental issues, and get informed. Show your support and share your concern for the wellbeing of this (and other) species!
  • Rear monarchs. At home or in classrooms, rearing wild monarchs and releasing them is a rewarding and educational way to contribute.
  • Participate in tagging and monitoring projects. Monitoring and tagging projects take place in the summer and fall for New Jersey Monarchs. You can also contribute simply by reporting your sightings on these websites.

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Beachnester Buzz: A Day in the Life of a Beachnester

Monday, August 8th, 2016

NEW, WEEKLY UPDATES FROM NEW JERSEY’S BEACH NESTING BIRD PROJECT TEAM

by Todd Pover, Beach Nesting Bird Project Manager

 

For this week’s installment, I thought it would be fun to have you tag along with me on a day in the field, so you can get a sampling of what goes into our beach nesting bird program. Let’s call it, “A Day in the Life of a Beachnester.”

 

skimmer

Black skimmer and chicks at our Belmar colony where we recently banded the young before they could fly. Photo courtesy of Jersey Shore Photography.

Today it is an early 4 am rise to beat the beach crowds and heat, as we are banding black skimmers at our Belmar colony. This is the first time our program has banded skimmers –  it is a collaborative effort with other organizations/agencies in both New York and New Jersey – we hope to find out more about their survival, longevity, and movement, both local and long distance. Everything goes well, we are able to corral and band about 35 chicks in less than an hour. This part of the day represents the science portion of the beach nesting bird project, science for the sake of study and a better understanding of our birds, but more importantly to gather information to help us manage and recover endangered species.

 

With no time to spare, it is now off to Leonardo along Sandy Hook Bay where CWF is hosting a summer wildlife experience for kids. No surprise, I am the guest today to teach the kids about beach nesting birds. I explain why piping plovers and American oystercatchers are at risk, and then give them a chance to use a high powered birding scope to try to read bands I have placed on decoy birds. We definitely have some budding biologists in the mix. Education is key to our project, unlike other endangered species that mostly live out of sight or reach, beachnesters spend the breeding season on the same beaches visited by millions of tourists and residents. If they are going to learn to “share the shore” with our endangered birds, outreach is essential.

 

beachnester buzz plant

Sea beach amaranth, a rare plant, that shares the beach with our nesting shorebirds and also is protected.

Next up is a stop at Seven Presidents Oceanfront Park, one of our important nesting areas in Monmouth County. For most of the season we are erecting and adjusting fence to protect nesting areas, but today we are working with the park to reduce the fence, as many of our birds have successfully nested and started to leave the area. First we count and locate any remaining least terns – these surveys are the base of our project – we need this data to track population trends and seasonal productivity as metrics of progress towards recovery. Before we remove any fence at this site, we also conduct surveys of sea beach amaranth, an endangered plant that shares the beach with our nesting birds. We locate a few plants and that dictates how we readjust the fence, the plants need protection from trampling by beachgoers or vehicles used by the park to maintain their beach.

 

 

Coordination with municipalities or other land owners that host beach nesting birds is a critical part of our project, as their activities can impact nesting success as much as beachgoer’s recreational use of the beach. So there is one more stop today to assess whether a maintenance request can be granted in a way that won’t put birds at risk. That done, it is time to start the two hour drive back to our office in Cape May County. I am ready for a nap, but no luck, as the truck becomes a mobile office to take care of other unattended business (while someone else drives of course). There are calls with several other towns, check-ins with our seasonal staff members that are spread out all along the coast, and finally dealing with a broken down vehicle (not ours fortunately) and a person who refused to take their dog off a nesting site.

 

Back at the office, it is one last check of email, entering a little bit of the data we collected today, and finally time to head home. Every day is a little different, but this day has been a good cross-section of the range of things we do on the project. It is tempting to think we just pop up fence and signs and hope the birds do well, but protection and recovery of our endangered beach nesting birds requires a comprehensive strategy addressing all the factors that impact nesting success.

 

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NJTV News: CWF’s Pover Discusses Piping Plover Conservation

Monday, August 8th, 2016

by Emily Hofmann, Assistant Communications Manager

 

todd on njtv news

 

Todd Pover, CWF’s Beach Nesting Bird Project Manager, recently sat down with NJTV’s Mary Alice Williams to discuss piping plover conservation on the anniversary of 30 years of federal listing. Listen in to what he had to say.

 

 

 

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New Jersey’s Hidden Coast – The Final Episode

Saturday, August 6th, 2016

NEW JERSEY’S HIDDEN COAST – EPISODE 6

by Emily Hofmann, Assistant Communications Manager

 

“Our work on the bayshore is not just about wildlife, it’s about people, and how keeping nature strong keeps us all strong in the face of disasters like hurricanes.”

 

We want to ensure that New Jersey’s Hidden Coast remains a vital part of our livelihood for generations to come.

 

This is the final episode to our video series, “New Jersey’s Hidden Coast.” Catch a glimpse of the Bay, the horseshoe crab at the center of the bay’s system, and the incredible relationship between horseshoe crabs and migratory birds, like the red knot. We reveal the real value of horseshoe crabs, the challenges to the ecosystem, and the potential for thriving regional economy along the bayshore. We will show Hurricane Sandy as a catalyst for decisive action and the work being done to rebuild the area for both people and wildlife.

 

Catch up on the previous episodes, here on our blog or on YouTube. Explore the use of “living shorelines” instead of bulkheads and the importance of marshes to the marine ecosystem. Discover the on-the-ground, grassroots efforts of the community to build oyster reeds alongside veterans. And examine the future of the Bay and the work that needs to be done to preserve our conservation successes year after year.

 

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