Conserve Wildlife Blog

Posts Tagged ‘raptors’

International Migratory Bird Day Series: American Kestrel

Friday, May 13th, 2016
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.


Learn More:


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

Photos from the Field

Thursday, February 4th, 2016
Productive Trip to North Jersey Falcon nests

by Ben Wurst, Habitat Program Manager

Kathy Clark, ENSP Wildlife Biologist and myself made use of our trip to North Jersey on Tuesday. Both being based out of S. Jersey, we try to maximize our productivity and time spent up north. We visited a total of three peregrine falcon nest sites to conduct winter maintenance at them. Winter maint. is in preparation for the start of their nesting season, which usually begins in mid-late March. Eggs are usually laid in late March-early April. On the list for usual maint. (which we do at over 12 nest sites throughout NJ) is to refresh gravel, treat for parasites, and check condition of predator guards (for those sites on former hacking towers). At the sites we visited yesterday, we had some additional work.

Our first stop was at the Union County Courthouse in Elizabeth. While fixing up the nestbox on the roof, we also helped with the installation of a new pinhole camera that was installed on the inside wall. The camera, paid for and installed by Union County, will stream online soon. CWF will help to promote the camera and our own Peregrine Falcon Cam curriculum. The female that nests here was not seen as we would have known since she is overtly aggressive to anyone who climbs onto the roof there. It could be the same female but it was odd that she was not seen at all. In addition, Kathy photographed the male who is banded (likely in NY – you can tell by the silver band he wears – we use black in NJ). The previous male was not banded. So, there could be a whole new pair here. Only time will tell if this site will be active this year. Having the camera there will help biologists learn about the turnover and if eggs are in turn laid by the female.

Second, we visited the Jersey City eyrie. There we removed the pinhole camera to get repaired/replaced. Then we painted the inside of the nestbox, which was showing its age and a good covering of guano. The female Juliette was there and not quite sure of our presence. Since she has not nested here yet, she does not attribute our presence with any kind of disturbance. This will change when she has young to protect.

Our last visit was to the PSE&G Sewaren Generating Station. Here we moved a new nestbox from one building to another. The story of this site is where young falcons were found on the ground after attempting to fledge a few years ago. Their nest site was found to be in an old and unused duct which was accessed by an open window on the north side of the building. Then last year the pair attempted to nest on a tiny ledge on the south side of the building, but the nest was flooded. Our site visit revealed that there was a suitable ledge above the tiny ledge and we moved the nestbox here. This will give them the best chance of successfully raising young. PSE&G staff were very willing to help and are proud that their generating is home to a pair of nesting falcons!

Cameras/photography can be used to document new birds at nest sites. This is a new male peregrine falcon (yet to be ID'd) at the Union County Courthouse. The previous male was not banded. Photo by Kathy Clark/ENSP

Cameras/photography can be used to document new birds at nest sites. This is a new male peregrine falcon (yet to be ID’d) at the Union County Courthouse. The previous male was not banded. Photo by Kathy Clark/ENSP

Kathy and I atop the Union County Courthouse. Photo by Betty Ann Kelly.

Kathy and I atop the Union County Courthouse. Photo by Betty Ann Kelly.

Prey remains atop the Union County Courthouse. Can you ID it? Photo by Ben Wurst

Prey remains atop the Union County Courthouse. Can you ID it? Photo by Ben Wurst

Juliette on a perch atop 101 Hudson St. Photo by Ben Wurst

Juliette on a perch atop 101 Hudson St. Photo by Ben Wurst

The inside of the Jersey City nestbox got a new paint job.

The inside of the Jersey City nestbox got a new paint job.

Our last stop of the day was at the PSE&G Sewaren Generating Station where we moved a nestbox to a new location at the plant. It was placed directly above a narrow ledge that the birds nested on last year. Photo by Ben Wurst

Our last stop of the day was at the PSE&G Sewaren Generating Station where we moved a nestbox to a new location at the plant. It was placed directly above a narrow ledge that the birds nested on last year. Photo by Ben Wurst

Conserving Barn Owls in the Garden State

Monday, February 1st, 2016
Insight into a Nocturnal and Enigmatic New Jersey Raptor

by Melanie Mason, Assistant Biologist


Barn Owls (Tyto alba) are one of the most widespread avian species in the world. Despite this impressive distribution, their numbers have been decreasing in parts of their range, and New Jersey is no exception. The extent of their decline isn’t fully known since barn owls are nocturnal and enigmatic, so it’s difficult to estimate their numbers. Although barn owls can travel great distances to disperse after fledging and to find prey, they don’t truly migrate. Therefore, there isn’t a breadth of migration data to sift through in order to triage their downward trend either.


The first step in species conservation is to understand its biology. Because barn owls aren’t migratory, they don’t have the intense energy requirements needed to fuel long distance treks to warmer climates, but the trade-off is they are at the mercy of their local prey abundance and availability. If you look at a distribution map of North American barn owls, you’ll see that New Jersey is close to the northernmost extent of their range. In fact, the majority of their subspecies/races are found in lower latitudes. Unlike their tropical kin, however, northern owls have to frequently survive freezing conditions and in order to do so, need food and lots of it!


Catching enough prey through New Jersey winters can be a challenge in and of itself, but if owls lack sufficient fat stores because of an unfavorable prey year (think hurricanes, floods, droughts, etc), they can easily succumb to cold conditions and die from exposure. The reality is that many young owls do not survive their first winter — a very steep learning curve.


Their preferred prey is meadow vole which are close relatives of lemmings — made famous for their explosive populations during favorable years. In order to respond to sweeping changes in prey availability, the reproductive strategy of barn owls is atypical for most raptors. Where small clutches and high parental investment are the norm, instead, barn owls are capable of breeding year round in favorable conditions (generally fall/spring here in New Jersey) and can have large clutches in order to respond quickly to prey availability. Another uncommon and well-documented strategy is polygyny — where one male sires and provides for multiple nests.


These reproductive strategies are important since barn owls are not a long lived species and typically do not survive much longer than five years. Their saving grace is their ability to “bounce back” and quickly repopulate local areas. This is where we can help!


Barn owls get their name from their close association with humans. They hunt in marshes, fields and grasslands typically favored for agriculture. They frequently nest in structures like old barns, buildings and silos. Constructed structures such as barns and nest boxes are generally preferred over natural cavities (dead or hollow trees for example) because they are safer from predators, more protected from the elements and have a vast supply of mice and voles at their doorstep. As silos and old barns fall down or are torn down in favor of newer, longer lasting metal structures, these nest boxes are even more critical to provide nesting opportunities.


The goal of our barn owl project is to provide safe nesting structures for barn owls in suitable habitat throughout the state. We also hope to gain insight into owl occupancy and nesting success in previously un-monitored areas of New Jersey.


Four ways to help barn owls:

  • Report any sightings, any time of year. While we are most interested in bolstering the breeding population, identifying winter habitat is critical as well.
  • Barn owls are better for the environment than barn cats since they are native and don’t kill songbirds, so consider housing barn owl instead! They’ll alleviate your rodent problem without the cost of feeding and risk of unwanted litters.
  • Don’t use rodenticides! They can harm or kill barn owls (and many other species too), plus owls often do a better job than poisons and are safer for everyone.
  • Know a potential location or just want to learn more? Email me at I want to hear from you!


The generous support of Washington Crossing Audubon Society provided quite literally the nuts and bolts of the fledgling nest box project by facilitating purchase of supplies for nest box construction — a million times thank you!


Learn More:


Melanie Mason is the Assistant Biologist for Conserve Wildlife Foundation of New Jersey.

New Jersey’s Bald Eagle Population Continues to Soar

Thursday, January 14th, 2016
Conserve Wildlife Foundation of New Jersey releases results of 2015 State Bald Eagle Report

by Lindsay McNamara, Communications Manager

A bald eagle flies over the Holgate Unit of Edwin B. Forsythe NWR on Long Beach Island. © Northside Jim

A bald eagle flies over the Holgate Unit of Edwin B. Forsythe NWR on Long Beach Island. © Northside Jim

Conserve Wildlife Foundation of New Jersey today released the 2015 Bald Eagle Report, highlighting the number of nesting pairs, active nests and nest productivity for the raptors throughout New Jersey with data collected by New Jersey Department of Environmental Protection Division of Fish and Wildlife biologists, CWF biologists and committed volunteers.


“With 161 pairs of bald eagles this past year — up from just a single nest in the early 1980’s — the dramatic ongoing recovery of bald eagles across the northeast continues to inspire so many of us,” said David Wheeler, Conserve Wildlife Foundation Executive Director. “The thrill of seeing a bald eagle fly across the sky is unparalleled. This report captures how these eagles are continuing their All-American return.”


The report notes that thirteen new eagle pairs were found this season, nine in the south, two in Central Jersey and two in Northern New Jersey.


With a wingspan of six to seven feet, bald eagles are larger than most birds. The bald eagle is restricted to North America and is usually found within close proximity to open water. In New Jersey, bald eagles reside year-round, usually remaining in the area surrounding their nest. They begin courtship and nest building in late December and January, adding to their existing nest. Over time, some nests can reach 10 feet across and weigh up to 2,000 pounds.


Conserve Wildlife Foundation partners with Duke Farms on a webcam that provides a live look at a bald eagle nest in Hillsborough, New Jersey. This spring, the EagleCam will allow viewers an up close and personal view into the lives of a pair of bald eagles as they breed, incubate, and raise young. Between the general public and classrooms up and down the east coast, the EagleCam has many fans – over 10 million viewers and growing!


The federal government removed the bald eagle from its list of Endangered Species in August of 2007, but the bald eagle’s official New Jersey status remains state-endangered for the breeding season and state-threatened for the non-breeding season.


“One of our encouraging findings is that the population of wintering bald eagles has grown along with the nesting population over the past decade,” said Conserve Wildlife Foundation eagle biologist Larissa Smith. “This growth reflects the increasing populations in New Jersey and across the northeast, as recovery efforts continue to pay off for eagles. In addition to our fellow scientists in New Jersey and nearby states, I’d like to thank the wonderful eagle project volunteers who make keeping track of all these nests possible.”


The Division of Fish and Wildlife’s Endangered and Nongame Species Program (ENSP) bald eagle recovery efforts, implemented in the early 1980’s, have resulted in a steady recovery of New Jersey’s bald eagle population. ENSP biologists, Conserve Wildlife Foundation of New Jersey staff, and volunteer observers continue to locate and monitor bald eagle nests and territories each year to analyze the state of the population. The state’s eagle population would not be thriving without the efforts of the dedicated eagle volunteers who observe nests, report sightings, and help protect critical habitat.


Highlights of the 2015 New Jersey Bald Eagle Project Report are found below or view the complete report online.


2015 Report Highlights

  • The statewide population increased to 161 territorial pairs in 2015, up from 156 last year.
  • Thirteen new eagle pairs were found this season, nine in the south, two in central and two in northern New Jersey.
  • One hundred-fifty pairs were known active (meaning they laid eggs), up from 146 last year.
  • One hundred twenty-two nests (81%) were known to be successful in producing 199 young, for a productivity rate of 1.33 young per known-outcome active nest, which is above the required range of 0.9-1.1 young per nest for population maintenance.
  • One chick, orphaned from a Maryland nest, was fostered into a Cumberland County nest and fledged, bringing the total fledged to 200.
  • Twenty-eight (19%) nests failed to fledge young.
  • The Delaware Bay region remained the state’s eagle stronghold, with 40% of all nests located in Cumberland and Salem counties.


Learn More:


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

The Return of Bald Eagles in New Jersey

Thursday, May 14th, 2015
Conserve Wildlife Foundation Releases New Story Map: “The Return of Bald Eagles in New Jersey”

By: Brian Henderson, GIS Specialist

Bald Eagle Story Map

Today, Conserve Wildlife Foundation of New Jersey (CWF) announced the release of “The Return of Bald Eagles in New Jersey” a Story Map that provides a new way to visualize the increasing number of bald eagle pairs nesting in New Jersey over time.


For years, CWF has worked closely with the New Jersey Endangered & Nongame Species Program (ENSP) to track and restore the bald eagle population within the state. It has been a rewarding experience for all involved to witness the return of bald eagles to the garden state, and now the public can appreciate the scope of their return as well.


The recovery of bald eagles nationally and in New Jersey is fairly well known, but some may not realize that as recently as the mid-80’s there was only a single pair of nesting bald eagles in all of New Jersey. The ban of DDT, combined with restoration efforts by ENSP biologists, resulted in population increases to 23 pairs in 2000, 48 pairs by 2005 and 82 pairs in 2010.


In 2014, there were a record 146 active bald eagle pairs nesting in New Jersey. This year, 190 nesting territories are being monitored and currently 88 chicks have been reported at 52 nests; it is still early in the season so we don’t have a count for all nests yet.


“The Return of Bald Eagles in New Jersey” Story Map displays the locations of all the known active bald eagle nests in New Jersey from 1985-2014. Users can choose to view the nests active in a single year or over a longer period of time. By choosing a one year interval and beginning in 1985, it’s possible to watch as nests multiply from a single nest in Bear Swamp to densely populating the Delaware Bay coast and spreading across the southern portion of the state and eventually into almost every county of New Jersey. In 2014, the only counties in New Jersey without an active bald eagle nest were Essex and Hudson.


The Story Map also highlights “featured” nests, or nests of special significance, including the Duke Farms nest which has been featured on a webcam since 2005 and the Millville nest where a juvenile eagle was fitted with a GPS tracking device in 2014. These featured nests include more information, pictures and links to pages that explore related projects in greater depth.


As the bald eagle population has reached record numbers in New Jersey, the raptors have expanded into non-traditional parts of the state, providing more and more people with a chance to glimpse this iconic species. This map highlights the ongoing success of conservation efforts and illustrates that whether you realize it or not, you’re never very far from a bald eagle nest in New Jersey!


Learn more:

Brian Henderson is the GIS Specialist for Conserve Wildlife Foundation of New Jersey.


  • Subscribe!

    Enter your email address to subscribe to the Conserve Wildlife Blog and receive notifications of new posts by email.

  • Support Conserve Wildlife Foundation

    Support our efforts to protect New Jersey’s rarest animals, restore important habitat, and foster pride in New Jersey’s rich wildlife heritage.

    Join - Donate - Adopt a Species
  • Get Connected

  • Recent Comments