Nantucket Osprey Watch
by Dr. Sarah Treanor Bois, PhD
Director of Research & Conservation at the Linda Loring Nature Foundation
A familiar sight along the harbor and around our many ponds, Ospreys are a common site as they dive for fish across the island. Ospreys (Pandion haliaetus) are iconic on-island, a part of our maritime community. Also known as Fish Hawks, they are abundant on Nantucket this time of year, having migrated back this way in late March. While these majestic birds of prey are now a fixture of early spring and summer on the island, that was not always the case.
Today Ospreys can be found in all 50 states, but they are still a species in recovery. Like many birds of prey in our region, during the early 1950s-70s their numbers were suffering in large part to DDT and other pesticides. This pesticide was widely used throughout the U.S. and could bioaccumulate through the food chain and be stored in the fatty tissue of the bird. In New England and along the Atlantic Coast, the breeding population of Ospreys was reduced to just 10% of pre-DDT levels. In 1973, DDT was finally banned and legislation was passed protecting these birds. Since then, Osprey populations have rebounded due to various conservation efforts.
On Nantucket, the first recorded Osprey nest was found in 1979, and the population has grown every year since. Thanks to the work of researchers—especially the Maria Mitchell Association’s Dr. Robert Kennedy—we have valuable data on Nantucket’s Osprey population from 1979 to 2015. Since then, there hasn’t been a full survey of nests across the island, but lots of anecdotal observations.
You may recognize the nesting platforms of the Osprey found throughout the island. Just look at the Linda Loring Nature Foundation (LLNF) logo! For decades, it was “if you build it, they will come,” with birds quickly occupying newly constructed nest platforms. Beyond the platforms, Osprey have now expanded to a variety of nesting sites, including old trees (their original preference), rooftops, radio tower poles, and even beach dunes.
On my own nature walks and field trips on the LLNF property, people regularly ask about the Osprey. The two most popular questions: 1) How many Ospreys are there on island, and 2) if we keep building nest platforms will there just be more?
A new program launched this spring will help us try to answer those questions with real data, not just educational guessing. The Nantucket Osprey Watch Program is an exciting new community science effort led by the Linda Loring Nature Foundation to study and support the island’s Osprey population. This project relies on the help of community m embers to observe, document, and raise awareness for the Ospreys that nest across Nantucket. The project is the brainchild of LLNF’s Master Bird Bander, Libby Buck, who said that the motivation for starting the project began with the Massachusetts Osprey Working Group.
“The Massachusetts Osprey Working Group asked me to help create a census for the island since Nantucket’s Osprey population has not been well documented in recent years. I saw this as a great opportunity to turn it into a community science project, something that would involve people from across the island and allow everyone to contribute observations and be part of the research. Every summer, people fall in love with the Ospreys here, and now we have a way for those observations to come together as shared data,” said Buck.
The project began with a basic “call to arms” and public outreach. A kick-off meeting introduced the project and answered questions. The recording can be watched at llnf.org/virtualprograms/v/osprey-watch-info-2025. The great volunteer response shows how much our community really does love Ospreys.
So what does reporting on Osprey involve? It’s actually pretty easy, and even just one report provides valuable data. Volunteers are invited to “adopt a nest” and report activity once a week via a simple online form. You can even enter photos of what you’re seeing. There is a lot of great background info and educational materials on the website and mentorship from Buck and her team. Buck has tried to make it as easy as possible by allowing people to submit observations using forms at llnf.org/nantucket-osprey-watch Once submitted, the map updates to show the most recent activity.
Buck notes that the first goal for the 2025 season is to find and confirm all the nests across Nantucket. In coming years, bigger questions can be explored, such as how to attract more Ospreys, why certain nest poles are successful while others are not, and what Ospreys are really looking for when they choose a nest site. These are questions we can only answer together with more time and data.
The project establishes a baseline, and all of the information collected will be sent annually to the state working group. It also allows us on Nantucket to compare seasons and trends with other monitoring projects around Massachusetts. This project is about building a stronger understanding of our local population and being part of something larger across the region.
As of this writing, the project has confirmed 48 nest sites across the island, and that number continues to increase each week. Of those, 41 are active, 35 are in the incubation stage (sitting on eggs), and 3 are still in the nest-building phase. Click on any of the nest locations on the map on the website (indicated by stars) and you can see the latest activity report plus comments from observers. Of the 48 total nests, 33 are on constructed Osprey poles and 13 are in trees, which is especially exciting to see. There is also one nest on a chimney and another on a radio tower. Buck said she has been pleasantly surprised by how many are choosing trees. It shows how adaptable Ospreys can be when they find the right conditions. The mix of nesting types is something she is paying close attention to as she and her team continue gathering reports.
On-island, hatching could start any day now. If you are watching a nest, you might not see the chicks at first, but you will notice a shift in adult behavior. The male will be flying out for fish more frequently, and the female will stay closer, tearing food for the chicks. They will also become quite noisy and frantic. It is an exciting time to watch!
When asked for some highlights of the project so far, Buck emphasized that the volunteer turnout has been fantastic. In terms of the birds themselves, some interesting preliminary observations have already come out of this work. No Nantucket nests are on navigational buoys or on any high buildings or structures downtown. That stands out since many other coastal towns often have Ospreys nesting on buoys or on tall man-made structures, but that is not the case here. Instead, there seems to be a strong preference for the west end of the island. Buck speculates that that may be due to the abundance of fish in that area, especially herring and white perch, which are key food sources for our Nantucket Osprey during nesting season.
Researchers are also paying close attention to the platforms that are not currently being used. If possible, adding sticks to create a “starter” nest might help encourage Ospreys to adopt those locations. Male Ospreys are very focused on finding or creating the perfect nest, and if they see a platform that already looks well-built, they are much more likely to move in and complete it. It is a simple action that could make a big difference in future nesting success.
At the end of this season, Buck plans to put together an annual report that will be available to everyone. It will include a summary of the data collected, observations from the field, and insights gained. She is excited to share the full picture of what has been such a successful start to the Nantucket Osprey Watch.
Anyone can get involved even this far into the season. Participants do not have to commit to monitoring a specific nest all season, though that is helpful if you have the time to dedicate. Every single report adds to our understanding of the Osprey population on-island. All the forms and information are available at llnf.org/nantucket-osprey-watch. As Buck said, “We are always excited to welcome new participants, no matter your level of experience. I believe there are more nests out there that haven’t been discovered yet and more help is welcome!
“This has been a great season so far, and I have to thank all the volunteers who have helped me along the way. Without their help, we would not have such detailed records or be able to find so many nests. This season has already far surpassed my expectations, and I truly cannot thank them enough,” Libby Buck says of the volunteer observers who have flocked to her project.
Nantucket Osprey Watch
