Conserve Wildlife Blog

Posts Tagged ‘osprey’

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). ūüôā

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. ūüôĀ

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…)

NJ’s Osprey Population Continues Upward Trend

Tuesday, February 7th, 2017
Results from the 2016 nesting season show very positive results. Statewide census planned for this year.

by Ben Wurst, Habitat Program Manager

Ben Wurst prepares to band two young ospreys. Photo by Northside Jim

New Jersey’s ospreys continue to defy my expectations. Since being tasked with coordinating the NJ Fish & Wildlife’s Osprey Project, I have witnessed the population grow from around 400 nesting pairs to an estimate 600. That’s a 30% increase in the overall state population. In addition, the productivity rate (a measure of the health for the population) has remained at level consistent with an increasing population. The results from last year were positive throughout almost all major nesting colonies that were surveyed.¬†I’ve never been more amazed by the shear resiliency and adaptability of a species.

(more…)

Giving Absecon’s ospreys a boost

Wednesday, October 26th, 2016
Volunteers brave rain and high water to benefit ospreys!

by Ben Wurst, Habitat Program Manager

 

Volunteers work on a flooded saltmash to remove an osprey nesting platform in Atlantic City.

Volunteers work on a flooded saltmarsh to remove an osprey nesting platform in Atlantic City.

I’ve been surveying osprey colony on Absecon Bay since 2008, after I moved to the local area. It’s been an area with a small but slowly growing colony. In 2008 there were a total of 11 active nests. This year there were 23 active nests. Productivity has been good with an average of 1.72 young/active (known-outcome) nest over the past nine years (more than double what’s needed to sustain the population). Many of the nests in this area were installed in 2005 for mitigation for nests that were removed when the ACUA installed large wind turbines off Route 30. But, some platforms that were placed near the turbines, have been slowly abandoned by ospreys. This year only one nest was occupied there and it did not produce any young.¬† (more…)

Time to Get Muddy!

Thursday, September 8th, 2016
Volunteers needed to help maintain and repair osprey nests

by Ben Wurst, Habitat Program Manager

Map of nests that are in need of repairs in Absecon, NJ.

Map of nests that are in need of repairs in Absecon, NJ.

We have an obligation to care for and protect our wildlife, and for me, that’s what drew me into my current position. Osprey nesting platforms have been a focus of my work over the past 10+ years. They are designed specifically for ospreys and if built properly, can withstand the impacts of severe weather, including coastal flooding, high winds, and storm surge. For ospreys these platforms protect their nests from predators and flood tides, but over time the extreme salt marsh environment takes its toll on them. With the added weight of the large, perennial stick nests it can shorten the life span of a properly built platform drastically. Over the years I’ve seen older nests topple, from the weight of the nesting material and aging hardware, during the middle of the nesting season during severe storms. This is hard to prevent at every nest, during every storm, which we know are becoming more and more frequent, but we are adapting and in turn, helping our ospreys become more resilient (and productive) in the end.

New stainless screws are installed in an existing osprey nest to help prevent future catastrophe.

New stainless screws are installed in an existing osprey nest to help prevent future catastrophe.

In the past we (myself and other volunteers who survey ospreys and help maintain platforms) used to visit a nest only once a year, during nesting surveys in late June and early July. At that time we would note the condition of the platform and if repairs were needed, schedule those for the seven month long non-breeding season. Those who have volunteered to help and worked with me, know the task at hand. Most tasks include using hand tools to construct nest platforms and perches and to install them. I always say the hardest part is getting the platform to the saltmarsh where they will be installed.

To help engage and inspire others to help care for our growing osprey population, we are looking for volunteers who live within the watersheds were we are planning to conduct repairs of osprey platforms. Tasks vary by watershed but most are to add new (stainless) screws to existing platforms, install predator guards/perches, clean off excess nesting material, and do any other repairs to platforms (including moving and replacing some). We are hopeful to meet some local baymen and fishermen who are looking to help keep the nesting population stable as it has been over the past 10 years.

The work will occur in mid-late October and will be carried out through these watersheds:

  • Barnegat Bay (Point Pleasant south to LEHT)
  • Great Bay – All nests here need new hardware and one nest needs to be replaced.
  • Absecon Bay – In this area we have four platforms to replace. Three will be moved and one new one installed. Four other nests need critical repairs.
  • Sea Isle – several nests here need predator guards and a couple need minor repairs.
  • Wildwood/Cape May – After the strong storms in late June hit this area, many nests need new platform (tops) and others need to be cleaned off.

If you are interested in being notified when these platform construction and repairs occur, please email me. Let me know what you are interested in helping with and if you have a boat (and a ladder!) that can be used.

  • 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