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Posts Tagged ‘osprey survey’

Studying the Ridgway’s Osprey of Belize: Part III

Monday, April 3rd, 2017
Braving the Caribbean Sea to Survey Turneffe Atoll

by Ben Wurst, Habitat Program Manager

Jay T. loads gear into Horace’s boat on Sittee River.

For the final leg of our survey of Ridgway’s ospreys in the northern most part of our study area, we set out for Turneffe Atoll. Turneffe Atoll is an archipelago of mangrove islands and coral reef that’s approximately 20 miles east of Belize City. It’s 30 miles long and 10 miles wide and Belize’s largest coral atoll. Luckily, it was declared a marine reserve in 2012, which protects it from future development. Turneffe is an amazing assemblage of different marine habitats which provide habitat for a variety of many different species of wildlife, including American crocodiles (more on this later!), conch, spiny lobster, manatees, dolphins, sea turtles, and many species of birds, coral and fish. The mangrove islands are large with taller trees on the interior of the island. This is where most, if not all, the ospreys nest. We left on Monday, February 20th. (more…)

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. (more…)

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…)

Osprey surveys completed

Monday, July 30th, 2012
Severe weather may have reduced productivity this year

by Ben Wurst, Habitat Program Manager

Surveys of nesting osprey have ended for 2012. Each year volunteers, state biologist and CWF staff complete nesting surveys of ospreys. These “osprey banders” complete “ground surveys” (referred to as ground surveys because they are surveying nests by land/sea, not by helicopter) that cover around 70% of the state population. The surveys are meant to keep tabs on the state population and data collected from the surveys are used to determine the health of the population. Young are also banded for future tracking. Next year a state wide aerial survey will be conducted; the last aerial survey was in 2009 where 486 nesting pairs were found. We won’t know the total size of the population until then. Nesting success is mixed this year and is highly variable by different regions, mainly because of severe weather.

I never heard of a “derecho” until this summer. According to Wikipedia it is “a widespread, long-lived, straight-line windstorm that is associated with a fast-moving band of severe thunderstorms.” A derecho hit Cumberland, Salem, Atlantic & southern Ocean County in the early morning hours on June 30th, right in the middle of the nesting season for ospreys. Weather plays a significant factor in the success of nesting ospreys. They nest in open areas, which makes them vulnerable to high winds and severe weather, and since they primarily feed on fish, water clarity affects foraging success.

“In South Jersey, Atlantic City Electric reported that 206,000 customers lost power from downed trees. Most of the outages were in Atlantic County, which prompted a county-wide state of emergency. Near Atlantic City, a boater died while trying to bring his vessel ashore. Officials believed that lightning struck a 104-year-old church in Longport and caused a fire that damaged the building. An elderly couple was killed when a tree fell on their house. In Vineland, damage was preliminarily estimated at $125 million. On July 19th, 2012, President Barack Obama declared three counties in New Jersey (Atlantic, Cumberland, and Salem) federal disaster areas. This assured disaster relief through federal assistance to local and state governments and some non-profit organizations.” (from Wikipedia.com) I also know that two people were killed while sleeping in a tent at Parvin State Park.

Kristin, an intern with CWF puts an osprey nestling back in the nest. © Ben Wurst

At this time most young were between 2-3 weeks old, with some a little older and some younger. All young are very vulnerable to severe weather, especially when wind gusts reach 70-100 mph, they can be easily blown from their nests and if not retrieved quickly could become food for ground predators or washed away with the tide. Winds gusted to 81 mph in Tuckerton, 74 mph in Absecon (Reported by the NJ State Climatologist Dr. David A. Robinson). In three areas that I survey (Absecon, Mullica River, & Little Egg Harbor) many young were either lost or blown from their nests and found dead or live on the marsh. In Absecon 9 of the 22 young produced had been lost or found dead on the marsh as a result of the storm. At a couple other nests to the north a few young were found on the ground shortly after the storm. Off of Great Bay Blvd. many nests that had young before the storm had lost them. One of our volunteers reported that many nests in Ventnor that were previously occupied had no young after the storm.

We can only hope that severe weather like this will not occur during the middle of the osprey nesting season again, but with a warmer climate these might become commonplace in New Jersey. One thing that we might consider is to take a long look at our current design for nesting platforms and look to see if we can make changes to allow for a deeper nest bowl. More of a problem is that some ospreys do not build substantial nests and use little sticks and branches, while others build large nests that are not easily blown away with the wind.

 

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