Conserve Wildlife Blog

Posts Tagged ‘raptors’

Studying the Ridgway’s Osprey of Belize: Part II

Tuesday, March 14th, 2017
Flat calm Caribbean and three young Ridgway’s!

by Ben Wurst, Habitat Program Manager


The flat calm beauty of the Caribbean sea.

February 18: Second Survey of nests surrounding Placencia

Our second survey began from Placencia, a small beach resort town on the southern coast of Belize, which is a beautiful place to visit if you’re planning a trip to Belize. It was flat calm that morning, which made for great boating, but it was extremely hot! Life in the tropics was finally setting in… We headed towards the first nest location, which was last surveyed in 2016 by Paul and his team. Paul and Alan have been surveying osprey nests in Belize since 2014, so all known nests have been mapped and surveyed over the past couple years. Through the continued surveys of these nests we should be able to determine if the low productivity of Ridgway’s (around .3-.4 young/active nest) can sustain the population in Belize (the southern most nesting colony of Ridgway’s throughout their range). The work performed as a part of these surveys is critical to their long term survival in Belize. The first nest we visited was very unkept; however a pair was present. This ended up being quite the common sight during this survey.

An unkept nest south of Lark Caye.

An adult female Ridgway’s osprey in flight.

Red mangroves growing in the Caribbean off Placencia.

We then motored to several other small Cayes and surveyed a total of eight nests (only two produced young, photos below). Many were abandoned so it was hard for us to determine their overall fate. Many (good looking) nests Paul thought had failed (once had young or eggs and were lost) since the nests did look like they have been used this year but there were no birds around during our survey. Generally it is hard to determine overall nest success unless you watch a nest throughout the entire nesting season, or find evidence of nest failure when visiting a nest. In New Jersey, I generally can tell when a nest fails or hasn’t by observing the behavior of the adults. If a nest is active (bird present) and it is defending its nest with no young or eggs then it failed. If the nest is active (bird present) and it flies away with no defense of nest/young, then I call that nest active and housekeeping (a term for a bird that starts a nest but does not produce any eggs/young). Lastly, a nest with no birds = not active. Either way – it is very difficult to determine the overall nest success with only one visit/nest/season. If I were to go back to Belize then I would go twice during the nesting season there, which runs from December – March/April (once when birds are incubating and once when they have young). 🙂

Kept or Unkept nest?? You decide.

While we try to determine the cause of failure to an active nest, we think about potential threats to nesting ospreys. A substantial threat to ospreys in coastal Belize should be no surprise to us in New Jersey. Coastal development was a huge contributor to the decline of ospreys throughout coastal New Jersey. In Belize, there are many resorts on the coastal Cayes and the desire for more. Could this be the beginning of the decline of ospreys in Belize?? I hope not, as humans and ospreys can live alongside each other in very close proximity. To develop a Caye, mangroves are first cleared and then sand/coral is dredged onto the island to “fill” it in. Raising the elevation of the island allows buildings to be built and lovely white sand beaches to be manufactured for the enjoyment of humans (and sand flies!). During our survey we saw this in plain view. A nest on Long Coco Caye was still present in a large mangrove tree, however a huge pile of fill dredged into a pile right next to the nest. If this happened during the nesting season then there is no doubt that this nest failed…but, where were the adults?? The more we think about this work and the ospreys of Belize, the more concern we have for their overall safety and stability of their population.

A looming threat to Ridgway’s ospreys is development of coastal Cayes.

While scanning shorelines brown pelicans were a common sight around Placencia.

Kept or Unkept house on a coastal caye? You decide.

Sadly, evidence of humans is all over Belize. Welcome to the anthropocene.

The beauty of a disappearing horizon in coastal Belize. 

A brown pelican thermoregulating atop a red mangrove.

We kept moving along with our survey and ventured outside of the previous survey route to check a small Caye for a nest. Success! We found a nice nest atop a huge almond tree on Moho Caye. Bonus! There were also two large young (5-6 week old young) making this our first productive nest of the day! The island was private and occupied by a friendly caretaker. We talked to him about the ospreys, and he was happy to share the island with them. This just goes to show that ospreys and humans can coexist on the coast of Belize.

Can you spot the nest? 

No need to climb this nest. We wouldn’t be able to anyway. Next week we might bring a small drone to help survey tall nests like this one.

Two young visible along with an adult and loads of plastic bags. 🙁

The guardian. We were glad to see humans and ospreys getting along just fine on Moho Caye and hope to see this in the future too.

We continued to head north and back to Sittee River. Navigating along the edges of the mangrove islands would not have been possible with our experienced captain and his mate, Steve. They really made every survey go extremely smooth. Having boated for the majority of my life, I can attest to the fact that anything can go wrong at any time. You definitely do not want to get into trouble when boating offshore in Belize! There is few other boaters who could offer help, no patrolling of Coast Guard boats, no SeaTow/Boat US, and many islands are totally undeveloped and without freshwater. We are lucky to have had such a great crew to be able to get to us to where we needed to go and then back safely!

Navigating through tiny mangrove islands in search of nesting ospreys!

First mate Steve keeps an eye out while approaching the edge of a Caye.

Our experienced guide and captain Horace.

Guiding Horace through a cut along the edge of a Caye.

Fishing resort.

Siesta time!

Osprey siesta time!

The last nest we surveyed on our way back to Sittee River was one on Channel Caye. This nest was remarkable. It was built in a large dead mangrove and had two visible young. After closer inspection with my camera, we believed that their could be three young, so we decided to climb up and use a mirror to get a view into the nest. Jay T. eagerly climbed the short tree and saw three young. The female took off from the nest as the young played dead, as they do in New Jersey. She was not as upset as our ospreys get (Ridgway’s are less disturbed than NJ’s ospreys and hence less aggressive, IMO) and flew over the nest several times and then perched on a nearby branch, which allowed me to get some great photos of her. We were only by the nest for a couple minutes and quickly departed to let her return to the nest. This was the first time that Paul has ever seen three young in a Ridgway’s nest, so very cool for us to see and document! We surely hoped that all three survived to fledge. Usually by the time they reached the age that they were (around 3-4 weeks), then their chances of surviving were much more likely.

All things considered, there are many concerning threats to ospreys in Belize: nest abandonment, coastal development, plastic marine debris, possible persecution?, and the combined threats from the effects of climate change but we can only hope that from our work we can help improve their chances of surviving.

Stay tuned for Part III where we cover the next two surveys out and back from Turneffe Atoll and Calabash Caye!

Channel Caye female perched on her nest.

Jay peers into the nest.

Female looks on as we exit the area.

The third and elusive nesting!

A cut through to Sittee River.

Sunset on Sittee River.

Studying Ridgway’s Osprey of Belize: Part I

Friday, March 10th, 2017
CWF contributes to conservation of Belizean ospreys

by Ben Wurst, Habitat Program Manager

A male Ridgway’s osprey perched near its nest on a snag off Blue Ground Caye. Photo by Ben Wurst

When I first learned of the work being done by Dr. Paul Spitzer and Alan Poole to study the breeding population of Ridgway’s ospreys (Pandion haliaetus ridgwayi) in Belize, I was instantly captivated. I first met Paul at the Raptor Research Foundation Conference in Cape May last October where he explained the study and the need for partners to assist with this years survey. Some of the aspects that immediately drew my attention was the fact that the estimated size of the population there was around 50 pairs, that those pairs nest exclusively on the coastal cayes (mangrove islands), and that their estimated productivity rate was around .3-.4 young/active nest. The coast of Belize is approximately 170 miles long and protected by barrier reefs and these mangrove islands. (more…)

Wildlife returns to the industrial Newark Bay waterfront

Tuesday, November 1st, 2016

by David Wheeler

Under the sweltering September sun, our team discovers the earth at our fingertips. We ready the manure, topsoil, and mulch, wield the pickax and trowel, and labor the wheelbarrow through the trees and up the slope of a tidal berm.



We plant 250 native shrubs and 580 native herbaceous plugs. We hammer in nest boxes, install pollinator houses, construct mounds of brush for local and migrating wildlife, and create nesting habitat for northern diamondback terrapin, an at-risk turtle species.

We lose ourselves in nature for the day.

A migrating butterfly flits past leisurely and I look up from the soil to wipe my brow. Suddenly I remember exactly where this newly vibrant natural ecosystem is. Nearly overhead, I can watch never-ending streams of commuters and tractor trailers motor past over one of the busiest bridges in the nation – the Newark Bay Bridge. Just across the bay, I can see heavy industry. Out beyond the fence, more industry – ancient, tireless, modern progress marching forward.


Yet on this morning, and those that follow, we now have ecological progress here as well, in a place that was written off entirely not so long ago. The Newark Bay region has suffered a century and a half of environmental degradation at the hands of industry and unbridled development.

This active industrial site is home to Firmenich Inc., one of the largest manufactures of fragrances in the world. We have transformed the land today to invite wildlife partners to help balance the scales of the region’s damaged ecology.


Green Darner dew laden on Echinacea.

These partners are vital to our environment, to our health, to the world around us. They are the butterflies and bees, the wasps and beetles, the flies and moths that make up an army of pollinators that in coordinated effort provide humanity with the lungs of our planet. Without these pollinators, native plants could not sink carbon dioxide and impart oxygen to our surroundings, every minute of every day. Without these pollinators, the bread baskets of the world would wither away, no longer filled with grains, fruits, and vegetables.

The natural partnerships don’t stop with the pollinators born forth from meadow creation. These partners extend to migrating songbirds and mighty raptors, small mammals and diamondback terrapins.

“If we give nature an inch, it’s going to take a yard. Give it a chance and nature will return,” says biologist Blaine Rothauser, who is directing the restoration for GZA Environmental. “Wildlife just needs an opportunity.”


Immature night heron with crab.

Nature’s inspiring return builds upon decades of ecological recovery in the region. Thanks to President Nixon’s Clean Water Act of 1973, the water began to get cleaner. Improving the water quality reanimated the food chain from the bottom up – phyto- and zooplankton, invertebrates and crustaceans reappeared. In turn, a fishery was reborn, which ushered in the return of herons, ibis, osprey, turtles, and even harbor seals – seen sunning on the banks of tidal shores in winter!

Yet much of the land around the water’s edge is still wanting.

“The restoration site is an important buffer habitat to a large portion of undeveloped tidal bay directly adjacent to the Firmenich complex,” says Rothauser. “Today we have 60 people planting a native community of shrubs, trees and plants on a formerly sterile lawn and an unnaturalized earthen berm. It is vital work that makes a real difference.”


The team has also created opportunities for rare species to nest. Above our heads, an osprey platform has been installed, empowering this magnificent fish-eating raptor to continue its recovery along Newark Bay and many other New Jersey waterways, industrial and remote alike.

A barn owl box offers one of our most mysterious nighttime predators the opportunity to set up shop in a beneficial area – where there is no shortage of rabbits and field mice to help control.


Close up of a barn owl.

Across the pond, a purple martin condominium-like house offers the ample space necessary for these communal swallows to reside, a home base where they can feast on flying insects.

With the first phase of the project almost complete, the second phase will seek to transform the site’s holding ponds into ecologically productive floating wetlands, bringing herons and egrets and other wading birds.

Ultimately, this project is envisioned as one that can be replicated just about anywhere along Newark Bay – or any industrial waterfront for that matter. All it takes is the willingness to look at a site’s land from a different perspective – and in so doing, to understand that the ecological benefits of bringing back many wildlife species aren’t negated by losing economic tradeoffs.

Instead they can mean parallel economic benefits. Natural pest control. Fewer landscaping and pesticide costs. Increased employee morale and productivity, with a newfound opportunity to recharge body and mind with a rejuvenating break outside, enjoying natural beauty and the engagement of your senses.


Images above from left to right – Killdeer, 12 Spotted Skipper, and American Kestrel.

New Jersey has long served as a primary engine for America’s industry and commerce – and in return has often been derided as the “Which exit?” land of nothing but turnpike and smokestacks. The Meadowlands just to the north of here bore the brunt of that reputation, yet in recent decades has made a mind-blowing ecological recovery to become a wildlife – and ecotourism – destination.

The waters flow south from the Meadowlands along the Hackensack and Passaic Rivers, and they come together in the Newark Bay. Now, that next wave of wildlife recovery and habitat restoration has arrived just downstream – along the Newark Bay waterfront.

For wildlife, it’s where the action is.


David Wheeler is the executive director of Conserve Wildlife Foundation and author of the book, Wild New Jersey: Nature Adventures in the Garden State.


All photos courtesy of Blaine Rothauser.


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

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