Conserve Wildlife Blog

Stormy Spring Impacts Osprey Productivity

November 15th, 2022

by Ben Wurst / Habitat Program Manager

An osprey nest with hatchlings on May 16, 2022. One of many nests that eventually failed to produce young this year.

Whenever we look at how ospreys are faring, weather is always taken into account. When we summarize and report on the results of our summer osprey nesting surveys, we also look at the local climate. Being situated along the Atlantic coast, our weather is influenced by the ocean. As aerial predators of fish, ospreys are reliant on favorable water conditions to forage.

Preliminary results of the 2022 New Jersey Osprey Project Census show that the osprey population was not as productive this year as they have been over the past ~20 years. This was largely due to a low pressure system (nor’easter) that stalled off the coast in early May — when the majority of pairs were incubating eggs. The strong onshore winds caused moderate coastal flooding, windy conditions, increased wave action and water turbidity, which made it more difficult for ospreys to find and catch prey in coastal waters. Males do 100% of the foraging from the onset of egg laying until young begin to fledge, so when they are unable to provide food, females must abandon their nests and eggs to forage for themselves. The nor’easter in May appears to have affected the outcome of many coastal nests and in some cases, complete colonies. Of course there are many other causes for nest failure but this year weather played a major role.

Whenever I give presentations about ospreys, I highlight how the outcome of a nest is directly linked to the male, his experience and ability to find and catch prey regulate how many young the pair can successfully produce. The behavior mentioned above (female leaving eggs unattended) was witnessed first hand during the nor’easter at our osprey cam on Long Beach Island, New Jersey. Viewers watched as prey deliveries by an experienced (16 year old) male and incubation exchanges were reduced for a period of at least five consecutive days. At times the male, named Duke, would be missing for the entire day. If and when he returned, it was usually without a fish. The lack of food caused the female to leave the nest for 20-40 minutes at a time to catch her own prey and feed. When the eggs are left unattended, they are vulnerable to predation. For this pair, luckily their eggs survived and they were still able to produce two young who successfully fledged. This was not the case at many other coastal nests.

This year our data shows that all but one osprey nesting colony (Delaware River Basin, in the northwest) in New Jersey suffered a reduced rate of reproduction (as compared to the last year and rolling five year average). Again, this is the effect of the weather we experienced in spring, which caused reduced availability of food during incubation and made eggs vulnerable to predation. Overall, staff and volunteers recorded a total of 642 occupied nests throughout the state during our summer nesting surveys.* Of those the outcome was determined in 503 pairs. A little over 300 were productive and the rest failed to produce young. Overall, 626 young were produced which is an average of 1.24 young/active (known-outcome) nest, the lowest productivity rate recorded since 2003.

Despite the reduced reproductive rate this year, the population has more than doubled over the past 20 years. Adults are living long, productive lives, like Duke at the Barnegat Light Osprey Cam, and many non-breeding young adults are visible during nest surveys. New nests are being established in other areas, expanding the range of ospreys. This is another clear sign that we are doing a good job of protecting the health of our coastal environment. Continuing our work to monitor the population is an important aspect of their continued recovery and stability, especially as our climate is changing at a rapid pace.

Full results will be published before the end of the year and will include data on the presence of plastics found in nests and re-sightings of banded ospreys. I can’t thank all of our members, partners, osprey cam watchers, volunteers and donors enough for supporting our crucial work with ospreys!! For those who want to contribute to our work, you can donate online, Adopt an Osprey or purchase some New Jersey Osprey Project merchandise. #thankful

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*data from Osprey Watch was not included in this preliminary assessment


// Bonus shots //

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4 Responses to “Stormy Spring Impacts Osprey Productivity”

  1. Denise Lang says:

    Sad to hear about the reduced productivity of the wonderful osprey this year. Such is nature which of course we can’t control. Grateful for the success of this program and all who contribute their time, love, and efforts.

  2. Freda Karpf says:

    I would like to volunteer to be a nest watcher. How can I get on a list or be notified about this? Also. there was a nest in Avon that was taken down this year. Do you know anything about that?

    thanks

  3. Ben Wurst says:

    Thanks, Denise. Yes, it was certainly sad to see so many empty nests this year, but there were glimmers of hope at those nests with young.

  4. Ben Wurst says:

    Hi Freda, I can email you some information about volunteering to watch nests in your area. I had hoped to do an online training this past spring but things got hectic, so I will plan to hold one in the new year.

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