Conserve Wildlife Blog

Posts Tagged ‘Pandion haliaetus’

Photo from the field

Wednesday, March 30th, 2011
Not your typical osprey platform!

by Ben Wurst, Habitat Program Manager

A 30 ft. tall osprey platform is installed at Fort Monmouth in Oceanport, NJ. © Ben Wurst

For the past two years we’ve worked with staff from the Army Corps of Engineers to enhance osprey nesting habitat within the Shrewsbury River Watershed inside Fort Monmouth in Oceanport, New Jersey. We first began work during the summer of 2009 when an osprey nested on a utility pole at the Fort. The pair had eggs when their nest caused $10,000 worth of damage to a transformer. To alleviate the problem the nest was going to be removed from the pole and the nest would have been lost.  Instead Joe Fallon, Chief of the Environmental Division at the Fort decided to install a new pole next to the nest on the live power lines. I met with Joe and gave him a platform “top” and braces to attach to the top of the new pole. After the new pole was installed the nest and eggs were moved. The adults immediately took to the nest platform and successfully raised two young that year. In 2010, they raised another two young that we banded with USGS bird bands.

After completion of work this spring there will be a total of 18 nesting platforms there (not including a nest on a light pole over a baseball field). We hope to use part of this funding to install more nesting structures on several islands to the west of Sea Bright and Monmouth Beach in 2012.

A Unique Opportunity

Tuesday, January 25th, 2011
Manasquan Reservoir Osprey nest repairs

by Ben Wurst, Habitat Program Manager

A "natural" osprey nest in a snag on the Manasquan Reservoir. Image courtesy Tanya Dinova, Monmouth County Parks.

On January 17th I was forwarded a message from fellow osprey conservationist and colleague Jon Rosky. Jon has been helping provide nesting structures for ospreys since the early 90s with his Osprey Recovery Project. Tanya Dinova, a naturalist/interpreter at the Manasquan Reservoir Environmental Center contacted Jon to get assistance with a snag (a dead standing tree) that held an osprey nest since 2008 on the reservoir. This past October a storm caused the snag to snap and the nest was lost.

Luckily this occurred during the non-breeding season, otherwise the nestlings would not have survived. Tanya reported that the nest produced 2 young in 2010 and 2 in 2009. Great results for a natural nest that is directly over water! One might argue to not do anything and allow ospreys to find another snag to build a nest on. There are multiple snags in the water that could provide another natural nest site. If we were not going to do anything then this would be the likely outcome. However, many of the snags are not large enough to hold an osprey nest and there is a good chance the nest could fall during the breeding season.

Ospreys return to the same nest site year after year. And young adults return to where they originated to reproduce when they are 3 years old. Ospreys usually live till around 10 years old in the wild. The oldest osprey that was ever encountered in New Jersey was a female that was 18 years old. She sustained injuries from a close encounter with an eagle near Avalon several years ago and did not survive.

Here you can see the extent of the damage to the tree. Image courtesy Tanya Dinova, Monmouth County Parks.

In her message Tanya stressed the importance of having ospreys that nest on the reservoir as an educational resource to visitors of the park. A total of 3 pairs of ospreys nest on the reservoir. Naturalists, like Tanya, educate the public about ospreys, their decline, their importance in the ecosystem, and their return to historic numbers in New Jersey. This is a very important part of the recovery of ospreys in New Jersey and it will help foster awareness for them in the future.

Monmouth County has been an area of interest to me. Since I began working with ospreys in 2004 there were only a few nests in Monmouth County that were monitored. In 2010 there were 14 active nests (not including those on Sandy Hook and the Raritan Bay) where nesting observations were made. These observations help us determine the health of the local and state populations. In 2010, productivity averaged 1.86 young/active (known-outcome) nest. It was recorded at 1.25 in 2009. The population is continuing to grow in Monmouth County and with only limited areas to nest, ospreys are nesting in peculiar locations.

Many ospreys are choosing to nest on cell towers, boat lifts, and other tall structures. Because of habitat loss these are the only a few structures that are available to them. Manasquan Reservoir is an exception. When the dam was installed it killed trees when the water levels rose. This created new nest sites for ospreys from the snags that were left. However, today many snags are beginning to decay and osprey nesting sites are lost.

This situation has created a unique opportunity to collaborate and find a solution. I suggested that instead of installing a new nesting platform, to install a box-top (3×3′ wood box) on top of the snag. The box would allow the ospreys to nest in the same tree and it would provide added stability ospreys rely on to incubate eggs and raise young. We will perform this delicate task before ospreys return in mid-March.

A healthy population

Monday, August 30th, 2010
Osprey numbers continue to rise

by Ben Wurst, Habitat Program Manager

Three osprey nestlings at a nest near Osbourne Island. © Eric Sambol

Ospreys are currently listed as a threatened species in New Jersey. They were first listed as endangered in 1974 after the state population declined to only 50 pairs, from over 500 prior to 1950. Ospreys have made a remarkable recovery in New Jersey thanks to biologists with the Endangered and Nongame Species Program (ENSP) and many volunteers. Surveys that help monitor the population were conducted in late June and early July.

Volunteers and biologists surveyed all major nesting colonies from Sandy Hook south along the Atlantic Coast to Cape May and west to Salem County. Ospreys almost exclusively nest on man-made structures including platforms designed specifically for them, cell towers, duck blinds, channel markers, and boat lifts. Surveyors visited these nest structures to observe whether or not they were occupied. If they’re occupied, then the number of young were recorded and the young were banded for future tracking with a USGS bird band. Preliminary results show that productivity rates are up for all nesting colonies except one (Sedge Island WMA). Since ospreys are predators, they are at the top of the food chain. They are considered to be an indicator species, or a species that is sensitive to changes in environmental conditions and can serve as an indicator of an unhealthy marine ecosystem. Basically, a healthy osprey population means a healthy marine ecosystem.

The climate during this summer has been the complete opposite as last year. It was hot, dry, and calm, with only a few severe storms with high winds that caused some nests to fail. Otherwise, fish stocks are plentiful, especially menhaden. This year many out-of-state commercial fishing boats have started fishing for bunker off New Jersey waters. This is mostly due to declines in herring stocks in New England and the high demand for bait for use in lobster pots. State legislators have introduced a bill that would limit boats from catching bunker for use as bait. Read more here and this press release from the Recreational Fishing Alliance.

Full results from this years survey will be published soon in our annual newsletter. Here is last year’s newsletter.

Lost Connection

Monday, August 2nd, 2010
To the internet, not wildlife!

By Ben Wurst, Habitat Program Manager

The office where I work, inside Tuckahoe Wildlife Management Area in northern Cape May County, recently lost its connection to the world wide interweb. The office is home to the NJ Division of Fish and Wildlife staff and three CWF employees. Since the demise of our connection to the world wide interweb the office has been ghostly quiet. Some have chosen to work at home, use some vacation time, or get some field work done. I just wrapped up my primary field season surveying osprey nests along the Atlantic Coast of NJ so I chose to be constructive, literally. I started constructing some artificial nesting platforms for ospreys. Normally I do this in the winter when field work is very limited, but finishing these now will give me a chance to install them this fall. Late summer and fall are the best times to install platforms. The water and air are warm and the winds are calm, so boots and bulky clothes aren’t required. So, I’m glad the internet is down because it gave me a reason to construct these platforms earlier than usual.

An osprey platform sits while I work on the finishing touches. This image was shot using a technique referred to as HDR. © Ben Wurst

Two platforms will be going up in Lavallette, one near Tuckerton, and the other has yet to be determined (possibly Sea Isle). Stay tuned for more updates and photos!


Photo from the Field

Wednesday, July 21st, 2010
An osprey nestling lays low in a nest

By Ben Wurst, Habitat Program Manager

The iris is the thin colored part of an eye that is responsible for controlling the size of the pupil and the amount of light that enters the pupil. As a hatching the iris of an osprey is blood red in color. As a nestling (pictured below) they turn to an amber or orange color. The eye color and plumage of juveniles help distinguish them from adults, which have a yellow iris. Juvenile ospreys also have “buff” or tan feather tips on their contour (body) feathers. This helps camouflage them before they can fly and it also helps distinguish them from adults, who have dark brown body feathers.

An osprey nestling relies on the cryptic coloration of its plumage to protect it from avian predators. © Ben Wurst

To see more photos of ospreys and their young, click here. Check out the slideshow at the top of the page.