“Ospreys build monofilament into their nests” – a tale of a hazard to one of Connecticut’s most visible bird species

July 25, 2019 – Monofilament fishing line poses a well-known risk to birds and seems to be especially hazardous for Ospreys. In one particularly appalling case last summer, monofilament line entangled a young Osprey on its nest platform in Fairfield County. We don’t know what killed a young Osprey at Harkness State Park in Waterford earlier this month, but when Melina Giantomidis, our Osprey Nation coordinator, went to check, she found monofilament line mixed in with the other nest material.

That illustrates a particular problem for Ospreys: they often incorporate fishing line into their nests, inadvertently. The fishing line does not breakdown or biodegrade, so it’s easy to see how an Osprey can get tangled in it.

The situation at Harkness brings up other uncomfortable realities.

With well over 400 active Osprey nests in Connecticut, no one – not the state, not Connecticut Audubon, not any of the local environmental organizations or bird clubs – has the resources to respond to every call or message about an Osprey in trouble. Nor is Connecticut Audubon licensed to treat or rehabilitate injured wildlife.

Wild animals, especially young animals, die or become injured all the time. Most go unnoticed. But Ospreys nest out in the open, and more than 300 Osprey Nation volunteers are watching, so it’s inevitable that deaths and injuries will draw attention.

And once an Osprey is injured, it’s chances of surviving are small. Wildlife rehabilitators tell us that unlike some owls and hawks, rescued Ospreys have a very low survival rate.

Throughout Connecticut there are dozens of monofilament recycling bins located at places where people fish. Click here for a list provided by the Department of Energy and Environmental Protection, and click here for information, including a map, about new bins recently installed in Bridgeport and Fairfield.

As for the situation at Harkness, three people deserve credit for making sure it didn’t turn out worse: Nancy James, the volunteer Osprey Nation steward for that nest, which we identify on the Osprey Nation map as Waterford #1; Melina, who drove 60 miles from her home on a Saturday morning to investigate; and Melina’s father, Tom Giantomidis, whom Melina recruited to help. 

Here’s what happened, as told by Nancy and Melina:

Nancy: On Tuesday July 9, I decided to check on a few nests after work, to make sure things were OK after the long holiday weekend. I saw two Ospreys perched on either side of the nest platform. I assumed they were the adults, or chicks that were ready to fledge. I noticed a stick about three- or four-feet long dangling from the nest. At that point I could not see exactly what was holding it there so I snapped a number of photos and headed home. 

Once I reviewed the photos later that night I noticed the stick seemed to be tethered by fishing line. Then I noticed the remains of a dead Osprey hanging off the perch below the nest. I decided that since the nest was still active there was a substantial possibility of entanglement of another member of that family. I had to try to alert everyone to the situation and see who might be able to help.

Like the other Osprey Nation volunteers, Nancy monitors her nests a few times each month and sends the data to Melina. She and Melina exchanged messages and spoke on the phone about what Nancy had seen at Harkness. Melina asked her father for help. “My father has a great understanding of what happens when fishing line is not disposed of properly and that this is a great threat to wildlife,” Melina said. “I convinced him by explaining the situation and proposing a game plan as to what we would be doing/how to go about it.”

Melina: On July 13th, we went out to Harkness. We saw one adult Osprey leave the platform. I went straight to the perch where the dead Osprey was, to examine it. The perch is behind the ladder, which is behind the platform in some of the photos. The dead chick had fallen off and was at the base of the perch. It was about 25 days old – it was a carcass, bones were visible, and it seemed like it was there for at least two weeks. No fishing line was on the carcass, it was not entangled in any type of string or line. 

My best guess was that it died in the nest (predation of some sort) and either the predator brought it to the perch and was chased off by the adults or the adults discarded the body from the nest. Ospreys are known to remove their dead offspring from the nest. 

Afterwards we set up the ladder and I climbed up and examined the nest. The only part of the nest that had fishing line was on the outer edges; there was not much but there was one particular part of the nest that had more than the other. I cut off as much fishing line as I could. The whole operation took about 40 minutes. 

Something to keep note of is Ospreys build monofilament into their nest. In this case the monofilament was hard to get out but there was enough hanging off the nest to pull it out. There was also a bottle cap that I removed from the nest. 

I have personally not seen an Osprey bring monofilament to the nests but have seen dozens of photos of them carrying fishing line to the nest to build. I can also tell by looking at a nest that the fishing line was used as part of the structure to build the nest. It’s found tucked into the nest versus on top of the nest. It’s not necessarily that they bring in just monofilament; it’s almost always the case that it’s attached to a stick or to algae that they plan to use for nesting materials. At least this is what I have observed after looking at many photos.

Photos on the right courtesy of Nancy James. As Melina and Tom Giantomidis set arrived at Harkness State Park and set up the ladder, Osprey steward Nancy James took photos from some distance away. The dead Osprey was originally suspended from the perch to the right of and below the nest in the photos. Melina found it on the ground under the perch. She also removed a length of monofilament fishing line from the nest itself, relocating the ladder from back to front to pull out as much as possible.