On the top of a tower just north of route 519 and west of route route 639, (the Warren Glen Rd) near the intersection of these two routes. It is across route 519 from the Warren Glen Academy and Pohatcong Park along the powerline cut.
Look for 2 adults on the nest. The adult pair will show pair bonding behaviors such as vocalizations, aerial sky dances, and the male feeding the female fish. You may see the pair copulating, which typically begins 14 days before laying eggs.
Females will lay 1 - 4 eggs at a rate of one egg every 1 - 2 days. After laying, incubation starts. Look for adults taking turns sitting low in the nest incubating eggs. The incubation period can last 35 - 43 days.
Chicks hatch ~39 days after incubation begins. Look for adults bringing food to the nest and making "head bows" into the center. Chicks typically can't be seen until they are 2 - 3 weeks old, so feeding behavior is the only way to know chicks are there.
Around 4 weeks after hatching, look for the heads of chicks to show over the rim of the nest, particularly when adults bring food to the nest. Other times they lie flat and are harder to see. Count the number of chicks in the nest before they learn to fly
Chicks begin flying around 7 - 8 weeks old, and are still fed by the adults. Count the number of chicks who have successfully fledged the nest and are observed flying.
Chick Last Observed
4 - 10 weeks after fledging, chicks begin leaving the nest area to migrate south, once they have learned to fly and feed themselves. Record the date that the last chick left the nest.
Look for signs of nest failure like adult abandonment, adults no longer incubating eggs or feeding young.
10:20 a.m. From the yard in front of Dan and Laurie's trailer, the managers of the Fibermark factory, now managed by IPPE, Rick and I heard eagle and osprey calls. A subadult/juvenile and an adult eagle were flying overhead as were two osprey adults. All were vocalizing loudly. I suspected that the eagles came too close to this osprey nest with its one chick. Perhaps this chick has fledged and was also in the air, but we could not tell. If it hasn't fledged it soon will as it was really wing-flapping a couple days ago.
10:40 a.m. Mom was sitting on the southwest edge of the nest and the chick was down and way in the back on the north side when I arrived. At 10:45, Mom flew off to the east, toward the river, circling around. The nestling raised its head and eventually sat up. While it was alone in the nest, the chick began to flap its wings energetically. It was sitting up when the adult female flew back into the nest and landed behind the chick. At 10:48, after being almost hidden in the far northern corner of the nest, Mom walked more toward the side I was watching on (southeast) and eventually both Mom and the female chick were sitting tall next to each other.
10:15 a.m. When I pulled over on the shoulder by the Musconetcong WMA sign, I could see the adult female sitting up on the southwest edge of the nest. It wasn't long before I saw the big wing stretch of the single nestling. Then the nestling started flapping its wings. By 10:25 I had seen and photographed a lot of energetic wing flapping by the nestling!
At 10:30 a.m. two guys came up to my window and it turned out to be Alex from kestrel banding last month and Rob Somes, who I know well because he was the eagle volunteer coordinator for the north half of the state back in 2018! The were heading to the river to do mussels surveys. We visited a while.
1:00 p.m. By the time I got to this tower, it was quite hot. The female was shading a single chick. I was able to see the chick clearly and take photos. Fortunately, the chick was positioned between my camera and its mother! I am convinced now that there is only one chick at this new (in 2022) nest. If there had been a second, or third, they would have been obvious today. The single chick appears to be quite mature.
9:00 a.m. I checked the nest prior to heading up the hill to the Quarry, but only could see the adult's tail feathers and the top of its head when it looked up.
10:00 a.m. I spent a lot more time watching after checking the Quarry and still, only saw the adult fussing with something way back and low in the nest. It was frustrating that the single chick was so far back and not active. I will hope to get good shots of this chick when it is older, sits up tall, and is more active. It is difficult to watch because both 519, 627 and 639 are quite busy and have no shoulders to speak of. This morning I did not even get great shots of the adult which spent most of its time sitting way back out of sight. You can see part of the nest from the Academy driveway/parking lot, but only if the birds are on the southwest side of the nest.
12:58 p.m. After registering this nest last year, the pair was simply "housekeeping" last season. No eggs. No chicks. I thought they were once again just present, but today I saw a single chick! I will return early in the morning to see if there might be more than one!! Once the chick(s) are bigger, I might be able to confirm a 2nd or even a 3rd!
1:05 p.m. An adult was standing, walking around with its head down, and appeared to be working on the bottom of the nest. It also sat low so that only its head showed. I assume this pair is "housekeeping" rather than actually incubating eggs. It would be one of three nests in the northwest quadrant of NJ that I watch, where the pair is present, delivering fish, eating in the nest and working on it, but not actually raising chicks. I hope eventually, this pair will get down to business!!
12:58 p.m. As we approached the bend where 519 turns north, we could see a pair of ospreys at the nest. The one which was on the post appeared in photos to have a brown "necklace" and thus be the female. The one that had been on the nest, flew off and was flying, circling around the tower when we were taking photos from closer in.
9:10 a.m. Once again there was an adult on the nest. It seemed to have brown spots on its breast which would indicate that it was the female. It was calling persistently and I saw at least 4-5 vultures circling overhead. One flew by the nest rather closely as seen blurred in the photo. I am not sure that is what had the osprey aggitated. Usually eagles and osprey just ignore vultures. From the photo it looks as though this bird that flew close to the nest may have been a crow or raven though. I did not get a good look at it as I took photos, but my impression at the time was that it was one of the circling vultures.
1:55 p.m. Today there was an adult sitting on the nest. I would guess this is a new pair, or at least a pair with a new nest location. They have continued to hang around the area after building a large nest, but had no eggs this season. It will be interesting to see what happens here next season.
We have observed a similar situation at the Three Bridges Eagle Nest Platform on the high tension tower. At Three Bridges an osprey pair also built up a stick nest and have been at the nest and in the area all summer but laid no eggs. Next season it will be interesting to see if the eagle pair returns, or the osprey pair remains at the Three Bridges platform.
12:20 p.m. I saw no osprey. It appears that after building a nice nest, this pair has failed to lay eggs this year. I hope they return and are productive next year. I wonder if this is the displaced pair from a mile south which had nested on Smiths Diary silo in 2020.
10:40 a.m. As I was driving from the Warren Glen tower nest, heading toward 519 north to check the Quarry nest, I saw a huge pile of nesting sticks on a tower at the intersection of route 519 north and the Warren Glen-Bloomsbury Rd northeast! I continued straight (northeast) not turning left onto route 519 and found a view of this tower across from a private home. I could get about halfway off the road and watched for quite a while. There was one adult which appeared to be sitting low on the nest. I couldn't tell if it was incubating, but it had a "necklace", so I assumed it was the female. Another flew in with an all-white breast which must have been the mate, a male. The first adult, the female, stood. The pair did a lot of nest-building/stick moving for a minute or so before the female flew off. The male continued to look at the bottom of the nest, move and rearrange, and then sat down where the female had been. Was this an incubation exchange? The female returned after a few minutes and stood wing flapping and moving around while the male stood, then wiggled down again. I presume there are eggs but will have to watch for longer periods. I then turned around and heading northwest up 519 to a driveway with a locked gate--the access road to the powerline towers. From that pull in I got a safe, good view off the roadway. This site is not very far (maybe a mile?) from Smith's Dairy, where nest #7924 was cleared away after the 2020 season, and a great horned owl model was installed to chase away the pair! This might be where they moved.