Oystercatcher nesting season is underway

By Emily Heiser, Wildlife Biologist

Many piping plover and American oystercatcher pairs have been busy laying their eggs over the last few weeks. As beach nesting bird biologists, we invest a lot of time into every pair at our sites. We revel in their successes and feel defeated at their losses. Unfortunately, many nests did not fare well in the April 25th Nor’easter that was coupled with new moon tides. Luckily, it is early enough in the season that all of them have begun, or will soon begin, attempting new nests.

The breeding habitat of the American oystercatcher in New Jersey consists of coastal beaches, inlet systems, and salt marshes.  Population estimates in New Jersey suggest 350-400 breeding pairs can be found here from March through August. Much of the monitoring and research done with American oystercatchers in New Jersey takes place on the coastal beaches where other beach nesting birds, such as piping plovers, least terns and black skimmers, are found. In 2016, more than 120 breeding pairs of beach nesting American oystercatchers successfully fledged 83 chicks. This was an especially productive year for those pairs and productivity levels were well above the target goal of .5 chicks per pair.

Photo courtesy of Sam Galick.

Oystercatchers arrive back on their breeding grounds here in New Jersey in early March to set up breeding territories and begin nesting.  Once paired up, adults typically lay one to three eggs.  Both the male and female will take turns incubating the nest for 28 days.  Once chicks hatch, they are semi-precocial, which means they are born in an advanced state, but are still reliant on adults for food and protection.  Oystercatcher chicks are fledged (or able to fly) 35 days after hatching.  After fledging, most Oystercatchers migrate to the southeast, but a wintering population does remain here in New Jersey.

American oystercatchers are listed as a Species of Special Concern in New Jersey.  A “Species of Special Concern” is a status determined by the New Jersey Division of Fish & Wildlife and applies to species that have an inherent threat to their population or have evidence of recent population declines.  Since American oystercatchers share the same habitat as other endangered or threatened beach nesting birds (piping plovers, least terns, and black skimmers), they also share the same threats to their nests and young.  Human disturbance, a host of predators, and flooding events, such as the one that took place last week, are just some of the many threats beach nesting birds face daily.

The Conserve Wildlife Foundation of New Jersey has long partnered with the New Jersey Division of Fish and Wildlife’s Endangered and Nongame Species program in the monitoring and management of New Jersey’s endangered beach nesting birds.  Fencing and signage are placed in nesting areas to alert beachgoers to the presence of nesting American oystercatchers and other beach nesting birds.  Throughout the summer, CWFNJ and partners will be out on the beaches monitoring and collecting data that will be used to track population trends and identify threats to oystercatchers and their young.

Emily Heiser is a wildlife biologist for Conserve Wildlife Foundation of New Jersey.


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International Migratory Bird Day Series: American Kestrel

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.

American Kestrel photo by Robert Lin.
American Kestrel photo by Robert Lin.

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.

 

KestrelRangeKestrels 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.

 

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

International Migratory Bird Series: Great Blue Heron

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.

Great blue heron by Howie Williams (8)
Great blue heron photo by Howie Williams.

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.

 

Great blue heron photo by Howie Williams.
Great blue heron photo by Howie Williams.

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!

 

RangeMapThe 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.

 

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