Weather & Climate

How it Affects Osprey Reproduction

2003 was one of the worst year's for osprey in New Jersey. Here is an excerpt from the 2003 New Jersey Osprey Project Newsletter:

"While the statewide average production was 0.86 young per active nest, it was somewhat better in Delaware Bay nests, at 1.09, than in Atlantic Coast nests, 0.73.  Productivity was depressed at all study areas, however, from Raritan Bay to Cape May to Delaware Bay.  Overall, productivity was down 27% from the 1997-2002 average of 1.18 young per nest.  This year it hovered close to the 0.80 young per nest considered necessary to maintain a population.

The most likely cause of this year’s nest failures is the weather during April and May, when ospreys were incubating and just hatching.  It was unusually cool and wet, and those conditions can have several implications for ospreys:  the high precipitation may have delayed fish migration and spawning, making prey harder to find; it may also have increased water turbidity, making it more difficult for ospreys to see fish.  As ospreys spent more time hunting with less success, their incubating partners may have been forced to leave the nest – exposing eggs or young chicks to weather and predators – to hunt for themselves.  In addition, we found that many young nestlings died when they were just two to three weeks old in June and early July, most from starvation, so the effects of the cool spring were far-reaching.  Unlike previous years when nest success declined in one region or another (primarily the Atlantic Coast), this year’s problems were statewide, which supports the theory that weather was the predominant cause." -- Kathleen Clark, Principal Zoologist, Endangered and Nongame Species Program.

Courtesy NJ Office of the State Climatologist.

No doubt we all know we had a HOT summer! It seems to have helped boost the osprey populations reproductive rate in all areas from Raritan Bay south to Cape May and west to Salem County, except for one area, Sedge Islands WMA. Its unclear why the Sedge population did not do as well this year. The productivity at Sedge varies from year to year, while the number of active nests has remained very similar (between 21 to 28 active nests from 2005 to 2010). Productivity peaked in 2008 and was at its lowest in 2003.

Courtesy NJ Office of the State Climatologist.

 A warm and dry climate will make nesting attempts more successful, while calm conditions will make foraging attempts more successful. Many bald eagle nests failed this year most likely from the wet conditions in February and March (when young nestlings are more vulnerable to harsh weather). Timing is everything. Osprey feed a variety of species of fish. Whatever is plentiful. This year menhaden was very plentiful off-shore. Boats from New England even came down to catch it for use as bait in the lobster fishery. Calm weather probably made it much easier to see and catch fish this year. Turbidity in water in calm weather is reduced so in-shore and off-shore waters were pretty clear. To be able to successfully raise young, male osprey need to supply a large amount of food to the female from coopulation through to when the young fledge (from early April to early-mid July). They need about 6 lbs. of fish a day to sustain themselves. Of 304 nests that were occupied (with a known outcome) 114 of them produced 3 or more young. Three nests produced 4 young. Outstanding results that will be summarized in the 2010 New Jersey Osprey Project Newsletter, which I'll be working on over the next week.

Osprey nestling giving Eric Sambol the stare down. © Eric Sambol.

On another note, we hit a whole bunch of milestones this year! Here's one: Volunteers and biologists surveyed more nests this year than any other year (when not conducting an aerial survey). 350 nests were observed as being occupied by a pair of ospreys. Previously the highest count was 288 nests. 70% of the population was covered this year! I just want to thank all our awesome volunteers who access many of these nests to band the young for future tracking and to all the other volunteers who report new nests in areas we don't routinely survey! Thanks!

Platform Work Continues and Some Nesting Season Results

On Tuesday, I got some much needed assistance with the installation of 3 platforms in Little Egg Harbor inside the Great Bay Blvd. Wildlife Management Area. This past winter and spring I had some friends help me construct 14 platforms. We installed 9 in March. More than half the new platforms were occupied this year, a couple nests even produced young, while others were simply "housekeeping" or practicing to nest.

Two of the three new platforms were placed next to old ones that will be removed this fall. The old platforms were unstable and in a state-of-disrepair. The other platform was placed directly across from the old Fish Factory (photos will come soon!).

An adult osprey flies by while conducting surveys in Little Egg Harbor. Photo by Bill Steiner

On another note, I've got some great news and nesting season results for you. The results are astounding. Truthfully, I did not think that the osprey population would have grown as much as they did in the past three years, but it has. Over the past 10 years or so population growth has slowed (from around 19% to 9%), which I believe is mostly due to a lack in nesting platforms. But since 2006 (when the last statewide survey was conducted) the population has grown by 19% to 475 nesting pairs, statewide. This is another record breaking post-DDT milestone. Historically, records showed that prior to the 1930's there were more than 500 nesting pairs of ospreys in NJ. After the effects of DDT, habitat loss, and persecution the statewide population was down to only 50 pairs in the 1960's. This prompted biologists to list the bird as endangered and work began to help the population recover. A large part of the restoration efforts were focused on erecting artificial nesting platforms. Today, you can tell that all the hard work done by biologists, like Pete McLain, Larry Niles, and Kathy Clark and the many volunteers have paid off. Their legacy will live on with the osprey as they continue to thrive in the most densely populated state in the United States.

Banding on Great and Little Egg Harbor Bays

On July 3rd I was out conducting ground surveys on Great Bay and Little Egg Harbor. My friend, Bill Steiner joined me to photograph the event. Below you will see a bunch of Bill's photos of the excursion. Some are excellent, where you can see the molting feathers of an adult in flight and that it is banded.

Here you can see that this female Osprey is banded on its right leg

and it's molting the 7th primary (flight) feather.

You can see the molting and band in this photo as well.

Here I am banding nestlings at a nest near

Osbourne Island in Little Egg Harbor.

This is one of the new nests that we installed in March from a

grant from Exelon. Of the 10 platforms we installed, 4 were occupied.

This has been a problem and will always be one. This chick had both its

legs wrapped in ribbon from a mylar ballon. If would have not visited this

nest within the next week, then this nestlings could have died due to

being entangled by the ribbon.

Me cutting away the ribbon to free the bird.

If you want to support ospreys in NJ, please

DO NOT buy Mylar balloons and release them into

the air for any reason!!!!!! You can see the negative

impacts that it can cause.....

Climbing to a nest in front of the Rutgers Marine Field Station at the end

of Great Bay Blvd.

At some point we were being followed

by an adult osprey. She followed us for approximately

1 mile away from her nest.

Here I'm entering data and you can see two addled eggs that I

collected for contaminant studies (if we get funding).

An adult Osprey dive bombs me as I band its young.

Thanks to Bill for taking all these great photos!

All photos are by Bill Steiner.

2009 Aerial Survey begins and Suburban nesting pairs, only in NJ!!!

This week, biologists with the NJ Division of Fish and Wildlife's Endangered and Nongame Species Program will be conducting an aerial helicopter survey. This is the first survey since 2006 when just over 400 nesting pairs were found, statewide. To read the newsletter from 2004, click here. The survey will determine how many nests are occupied and will give us some insight into how healthy the population is. The survey will also be conducted in mid-June to determine the outcome of all the nests and will help us calculate the productivity rate or the number of young produced per nesting pair. So, if you see a helicopter buzzing over osprey platforms along the coast, do not be alarmed! 

Vote in my poll for the number of nesting pairs you think we will have this year.

 Photo by Peggy Davis

On another note, a concerned citizen spotted a pair of ospreys that were building a nest on a boat lift on Blackberry Bay in Oceanport. She called our office and I spoke with her about the issue and started my hunt to find out who the owners were of the property. After several calls to the local township office, NJDFW Law Enforcement, then DEP's Land Use Regulation Program, I eventually found out the owners name and phone number. Basically, our position was to inform the homeowners of the occurance and to let them know that the nest could be removed, with special permission. The nest could only be removed if there were NO EGGS; if there was eggs, then they would have to get a permit from US Fish and Wildlife Service. So today I called the owner and spoke to her about the nest. I was surprised to know that she already knew about it and was not concerned!!!! She is actually happy to give up her boat lift and dock for the summer to give a pair of ospreys a chance to raise their young. This is great news! For the most part, I would have thought that most people would not want to give up the use of their dock and boat lift for a season, but this is not the case! I hope we do not see any major storms this spring and summer that could possibly blow off the nest and cause the nest to fail. Time to wait and see....
The hard part will be to try and get permission from a local private landowner for us to install an artificial nest platform near the site so the pair has a place to nest next year.