Tag: IMBD 2016

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.

CWF is celebrating International Migratory Bird Day all Week Long

by Lindsay McNamara, Communications Manager

CWF’s blog on the American kestrel is the fifth 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.

In New Jersey, catching a glimpse of an American kestrel is a rare treat! These beautiful, colorful birds of prey are about the size of a mourning dove — they are the smallest falcon in North America. Kestrels are one of two falcon species that nest in New Jersey.

 

American kestrels are opportunistic hunters, feeding on a number of different animals like grasshoppers, lizards, mice, snakes and small birds. Unlike peregrine falcons, kestrels don’t use speed to kill their prey. They perch to see their target and then use a stationary, hovering flight that allows them to dive down short distances to capture their prey. The eyespots of a kestrel make it appear to be “looking” up at its aerial predators, like Cooper’s hawks, causing the predators to move on to find a less “alert-looking” target. The eyespots give kestrels the opportunity to focus on hunting for prey beneath them.

 

Kestrels also hide surplus prey in grass clumps, tree roots, bushes, fence posts, tree limbs, and cavities, to save the food for lean times or to hide it from potential thieves!

 

Kestrels utilize these hunting tactics in open, grassy habitats — especially ones with cavities for nesting and perches for hunting. Kestrels can be seen hovering in grasslands, pastures and parklands or perched along the road on telephone lines.

 

Kestrels can be found in both North and South America, from Alaska and Canada in the north to Argentina in the south. During winter in North America, they will migrate southward from the northernmost portion of their range. They live year-round within New Jersey.

 

Although the American kestrel is widespread, meaning they live year round throughout much of the United States, the northeastern kestrel population is declining. Today, the kestrel is listed as a threatened species in New Jersey.

 

The decline of kestrels in New Jersey is likely due to destruction of grasslands from development. Nesting cavities are also being lost. As humans clean up fields, we remove trees with nest cavities that kestrels use. Kestrels are secondary cavity nesters. They don’t make their own cavity but use existing natural or man-made cavities.

 

Since kestrels nest in buildings and other man-made structures, nest box programs are an effective way to help grow the number of kestrels in areas where nest sites are limited.

 

Conserve Wildlife Foundation of New Jersey, in partnership with the Endangered and Nongame Species Program implemented a nest box installation and monitoring program in 2006. Nest boxes have been placed in areas of habitat determined to be suitable for the birds of prey. The boxes are monitored by biologists during the breeding season. Because kestrels reuse nest sites, particularly if they have successfully raised young, we focus on boxes that have been successful at least once since 2006.

 

The nest box program in New Jersey appears to be successful; we are adding to the population. Since 2006, we have banded over 300 fledglings. You can help too! Next time you see an American kestrel in the Garden State, be sure to submit a Rare Species Sighting form.

 

Learn More:

• Conserve Wildlife Foundation’s online field guide: American kestrel

 

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

CWF is celebrating International Migratory Bird Day all Week Long

by Lindsay McNamara, Communications Manager
CWF’s blog on the great blue heron is the fourth 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.

Have you seen a great blue heron wading in the marshes of the Garden State? While they are commonly seen along shorelines, river banks, and the edges of marshes, estuaries, and ponds, the breeding population of these wading birds is actually listed as a Species of Special Concern in New Jersey.

 

The term ‘Species of Special Concern’ applies to wildlife species that warrant special attention because of some evidence of decline, inherent vulnerability to environmental deterioration, or habitat modification that would result in their becoming a Threatened species.

 

Due to its wide distribution, varied diet, and flexibility in nesting near both freshwater and saltwater environments, the great blue heron’s population in North America is stable. However, wetland destruction in New Jersey has caused a decrease in heron populations from their historic numbers. Since the 1950s, habitat loss has occurred at an alarming rate in New Jersey, destroying wetlands critical to breeding herons.

 

Protecting our wetland habitats from disturbance and development will help protect the great blue heron, the largest wading bird in North America. Great blue herons are 46 inches long and have a wingspan of 72 inches. Despite their large size, great blue herons only weigh 5 to 6 pounds, in part because of their hollow bones — a feature all birds share.

 
Great blue herons can hunt during the day and night, thanks to a high percentage of rod-type photoreceptors in their eyes that improve night vision. They eat nearly anything within striking distance, including fish, amphibians, reptiles, small mammals, insects, and other birds. Herons nest in colonies or “rookeries” in tall trees near bodies of water.

 

The oldest great blue heron on record was found in Texas when it was at least 24 years, 6 months old!

 

The great blue heron occurs throughout most of North America, from Alaska and eastern Canada in the north to the northern portion of South America in the south. Northern populations of great blue herons east of the Rockies are migratory.

 

They withdraw from the northernmost portion of their range during the winter, some traveling to the Caribbean, Central America or northern South America. This species breeds throughout New Jersey. They generally do not occur within the northwestern corner of the Garden State during winter. Great blue herons migrate singularly or in small flocks, mainly in daytime.

 

We still have much to learn about the biology and population status of great blue herons in New Jersey. Research needs to be conducted to find additional breeding sites, check existing nesting areas, and determine whether the population might be decreasing or increasing. You can help! Next time you see a great blue heron in the Garden State, be sure to submit a Rare Species Sighting form.

 

Learn More:

• Conserve Wildlife Foundation’s online field guide: Great Blue Heron

 

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

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.

CWF is Celebrating International Migratory Bird Day all Week Long

by Lindsay McNamara, Communications Manager

CWF’s blog on the piping plover is the second 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 piping plover – a small sand-colored shorebird that nests in New Jersey as part of its Atlantic Coast range from North Carolina up to Eastern Canada –weighs only one to two ounces and is about six to six and a half inches long. These tiny shorebirds migrate all the way to their wintering grounds along the coast of eastern Mexico and on Caribbean islands from Barbados to Cuba and the Bahamas.

 

Migrants can be seen in New Jersey from early March to late April and again from mid-July to the end of October. Females are the first to leave the breeding grounds, followed by males, then juveniles. Breeding plover “hot spots” in each coastal county of New Jersey are Gateway National Recreation Area – Sandy Hook Unit, Barnegat Light, North Brigantine Natural Area and Stone Harbor Point.

 

We see a number of migratory piping plovers in New Jersey because the Garden State is roughly in the middle of their breeding range. Todd Pover, CWF’s beach nesting bird project manager, reasons that we have a high number of Eastern/Atlantic Coast Canadian breeders that stop in New Jersey — based on band resights — albeit usually for just a day on their way north to breeding grounds. Therefore, New Jersey may play an important role in the piping plover life cycle not just for breeding, but for migration as well, which emphasizes the importance of protecting shorebirds in all phase of their lives or “full life-cycle conservation”.

 

Piping plovers face a number of threats, including intensive human recreational activity on beaches where they nest, high density of predators, and a shortage of highly suitable habitat due to development of barrier islands and extreme habitat alteration.  Sea level rise and increased storm activity related to climate change will also likely lead to more flooding of nests.

 

Federally listed as a threatened species in 1986, piping plovers have since recovered in some areas of the breeding range. Yet piping plovers continue to struggle in New Jersey, where they are listed by the state as endangered. For more information about piping plover nesting results in New Jersey, please read Conserve Wildlife Foundation’s 2015 report.

CWF, in close coordination with NJDFW’s Endangered and Nongame Species Program, oversees piping plover conservation throughout New Jersey. Staff and volunteers help erect fence and signage to protect nesting sites, monitor breeding pairs frequently throughout the entire nesting season from March to August, and work with public and municipalities to educate them on ways to minimize impacts. Although conservation efforts on the breeding ground remain the primary focus, in recent years, CWF has also begun to work with partners all along the flyway, in particular on the winter grounds in the Bahamas, to better protect the at-risk species during its entire life-cycle.

 

We are working hard to link students across the piping plover’s flyway through our Shorebird Sister School Network, where we pair up schools in New Jersey and the Bahamas, one of the most important wintering areas for Atlantic Coast piping plovers. Now, we are hopefully recruiting some Canadian students as well.

 

Conserve Wildlife Foundation will continue to find innovative ways to save the small migratory shorebird. In 2015, 108 pairs of piping plovers nested in New Jersey, a 17% increase from 2014. What will 2016 bring? Follow us on social media to learn more about the tireless efforts of a team of passionate, dedicated biologists working to save the iconic coastal species.

 

Learn More:

• Piping Plover Nesting Results in New Jersey: 2015
• Conserve Wildlife Foundation’s Species Spotlight: Piping Plover
• Conserve Wildlife Foundation’s Online Field Guide: Piping Plover

 

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

CWF is celebrating International Migratory Bird Day all week long

by Kelly Triece, Private Lands Biologist

Kelly Triece’s blog on the Golden-winged Warbler is the first 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 Golden-winged Warbler (GWWA), Vermivora chrysoptera, is a Nearctic-Neotropical Migrant songbird that spends half its life in Central or South America and the other half in North America. This small songbird is less than 5 inches long with a slim body and short tail. GWWA are most noted by their yellow-patched wings, yellow cap and black-and-white face.

 

Right now, GWWAs are migrating to their breeding habitat in North America. They return every spring to the Upper Mid-west and Appalachians, including New Jersey, where they find a mate, breed and rear their young. The breeding range of the Golden-winged Warbler extends along the Appalachians from the northern portion of Georgia in the south to Vermont in the north.

 

Our latest report from the online observation database, eBird, reported a Golden-winged Warbler sighting in Cameron County, Texas on May 3! They are currently migrating north, and do so mostly at night. GWWA migrate at night to avoid predation from day-time predators such as American crows or Blue jays. The skies are also friendlier at night with less turbulence, allowing the birds to stay the course more readily. In addition, migrating birds need to forage to maintain energy during the long migration and must do so during the day. So flying at night gives the bird’s ample time to chow down! Get ready New Jersey!

In September, after breeding season, Golden-winged Warblers migrate south, mainly through a corridor of states east of the Mississippi River and west of the Appalachians. The winter range for this species is southern Mexico and Central and South America, including Colombia and Venezuela. Migrants are seen most commonly in late April and May, and during September.

 

Recent studies have shown that Golden-winged Warblers can also migrate in response to storm events (Streby et al. 2015). While GWWAs migrate long distances twice a year to occupy their breeding and wintering habitat, they may also “mini-migrate” to avoid large storm systems. Last year, a study in Tennessee found that Golden-winged Warblers evacuated their breeding territories days before a large storm system. After the system they returned to their breeding grounds and continued to defend their territories and breed. This research is important as it may provide future insight into the energetic demands and fitness consequences of these “mini-migrations.” As climate change continues to increase the frequency and severity of large storms along the east coast the “mini-migrations” may impact the overall fitness of the species as the energetic demands of migrations are great (Streby et al. 2015).

 

Golden-winged warblers are threatened due to habitat loss in their breeding range and wintering range. Golden-winged warblers require early successional, young forest habitat to nest and raise their young. Young forest habitat, also known as scrub-shrub habitat, is new or regenerating forest that is less than 20 years old.  In its breeding range in North America, habitat loss has occurred as forests have matured. In the past 30 years, over 11,000 acres of upland shrub and emergent wetland habitat have been lost to succession in New Jersey. In a naturally occurring system, where fire, wind, flooding and other disturbances are not controlled by humans this age class would be more evenly distributed. In addition, loss of quality stopover and wintering habitat may also be contributing to declines. Golden-winged warblers are a federal species of concern and endangered in the state of New Jersey. Through management and proper forestry techniques, more diversity can be created to balance the age of the forest. This type of forestry management can help protect the Golden-winged warbler in its breeding range.

 

Learn More:

• Check out our last GWWA blog post about research taking place on the GWWA wintering grounds!
• Conserve Wildlife Foundation’s online field guide: Golden-winged Warbler
• Providing Young Forest Habitat for the Golden-winged Warbler

 

Kelly Triece is the Private Lands Biologist for Conserve Wildlife Foundation of New Jersey.

 

Reference: Streby, H. M., Kramer, G. R., Peterson, S. M., Lehman, J. A., Buehler, D. A., & Anderson, D. E. (2015). Tornadic Storm Avoidance Behavior in Breeding Songbirds. Current Biology, 25(1), 98-102. doi:doi:10.1016/j.cub.2014.10.079