Sad News Regarding Arlington Eagle

[PAUL ROBERTS]

I'm sad to report the unexpected death of FAE (Female Adult Eagle), the mate of KZ who for six years has been the territorial male of the Mystic Lakes. The cause of death is unknown. Her body has been recovered by Mass Wildlife and taken to the Wildlife Clinic at Grafton for examination and testing. It could be weeks before results are known.

       FAE had been KZ's mate since February 2023, following the "recovery/removal" and death of MK, KZ's first mate, from Mt Pleasant Cemetery. FAE was in MK's nest with KZ within hours of MK's capture for treatment and rehabilitation. They bonded and later copulated. It was already late into the local Bald Eagle breeding cycle, with nests usually having eggs between mid-February and mid-March. Late February was very late to begin, but FAE apparently laid eggs as she and KZ appeared to incubate eggs for more than two months without success. Not unexpected.

        In July 2023 the nest MK and KZ had built on top of an old Red-tailed Hawk's nest in Mt. Pleasant Cemetery crashed to the ground following a soaking rainstorm. The nest, which MK and KZ had expanded every year, had simply grown too large and too heavy for the main supporting branches, which broke crashing the nest to the ground.

     FAE, whose favorite "break" area had been the pine tree complex where MK and KZ had built their first nest on the western shore of the lower Mystic Lake, decided to build a new nest in the same tree. She and KZ strengthened their bonds as they tore down the unmaintained nest and built a new, improved one together in exactly the same location.

     FAE was so named because she had not been banded. She had no "history" for us. We have no idea where she was hatched or grew up, and when, but I had the impression that she was very intelligent, very wary of human beings, and possibly had been mated before. Whatever, she was very alert to "eagle events" in the metropolitan area so she was aware when MK had not been flying above the canopy for several days and took advantage of the opportunity.  

     They laid the first egg in late March 2024 and raised three young who hatched about an amazing 14 days apart. The kids were banded and fledged. The smallest, 91/C fledged first, but broke a wing trying to fly back up into the nest. She was recovered and rehabbed by Tufts (Grafton). The other two nestlings fledged but died of unknown causes within 100 yards of the nest. (There was no evidence of rodenticide poisoning being a factor.)

     In 2025 FAE laid the first egg earlier, around March 8, and fledged three kids successfully. All three were banded, and last month 76/C was photographed on the Concord River in the Lowell area, the first field "report" of any of FAE's kids. 

     FAE seemed "experienced," savvy. KZ and I learned that when FAE incubated overnight she wanted to be relieved within minutes of dawn. Usually the first 5, but at times she would give KZ up to 15 minutes to relieve her before her anger became apparent. Twice she laid 3-egg clutches, and fledged all 6. She made sure EVERYONE got ample food. When the first egg would hatch, she would take only a brief restroom and breakfast break before returning to the nest area and doting over the kid(s). Last year she seemed perturbed on occasions where she would demand that KZ give her the food he had brought in so she could feed each chick properly herself. Fledging 3 chicks a year is well above average, and so was she.      

     I think the last time I saw FAE was Tuesday evening, when she settled into her nest. I was hoping she might be readying to lay her first egg of the season that night or early the next morning. When I went to look for the dawn nest exchange, I did not see her. I saw only KZ posting up near the nest, as though he was checking to see if she wanted relief.

     I was hoping to see her incubating, so came back twice during the day to check. 

No luck. I saw a few immature eagles that were looking for free meals from the "ice out" on the lakes, but no confirmed FAE. Then I saw a kettle of six huge, dark birds over the "western ridge." My first thought was Turkey Vultures in early March, but they were all eagles, at least two of which had some white on their heads, but they were extremely high and distant. They probably wouldn't have been seen if I hadn't followed a raven that flew a considerable distance and altitude to harass them.

      The light was terrible, but they gradually descended. Three continued south while 3 remained around the western ridge. One was KZ, and I thought one might be FAE, a large adult female. Then I saw KZ go into the nest, to the 10 o'clock branch. An apparent adult female stood up and cackled. I thought I saw an Osprey-like stripe on the head like a 3-year-old. She took off and flew towards us. As she lifted off the nest, I saw she was "salt and pepper" on her underwings. The female in the nest with KZ was definitely not FAE. I had not seen any aggression by anyone. I knew what this probably meant. I also noticed a thin terminal darkish tail band on the eagle. KZ followed her up the upper lake. Meanwhile, I lost track of the second larger eagle to the south.

    I was there at dawn this morning. Before sunrise (there was none visible) two shadows appeared on the 9 o'clock branch of THE eagle tree. KZ and SALT. (Yesterday I tracked her in my notes by a five-letter name that rhymes with witch. )

She had some salt (white feathers exposed) on her back, but not nearly as much as on her underwings and breast/belly. At one point she flew south and perched on the southwest spruce, where she was joined by another subadult female with weak osprey-like eye stripes. Two teenage females looking to move into a beautiful gated community with a wealthy, accomplished territorial male.

     Ironically, KZ perched not far away. Lower down. In a birch tree on the shore. Then Anna Piccolo noticed something on the ground. Black body with a white head and tail. FAE's body. KZ perched on the black metal fence just a few feet from FAE's remains, as though trying to work his way through what he saw. Talking to neighbors on the shore, they remarked about an adult eagle spending much of yesterday perched in the birch just feet from FAE, but the neighbors did not see the corpse. I felt for KZ. 

     I think FAE probably died very early yesterday morning, and that the news reached the local "eagle network" within hours. I think we may have seen SALT earlier this winter (have to checked my notes and photo inventory), but two 3-4 year old females with Osprey-like eye-stripes had not been regular in the area the past several weeks. It is not yet clear if SALT is KZ's mate of choice, but she is the only one I've seen in the nest with KZ. And perched side by side with him in THE eagle tree just after dawn. Time will tell. They can't waste much time. Maybe there is time for them to bond, copulate frequently, and contribute eggs to the future of the species. Scant time. The odds are not good, as they weren't for KZ and FAE in 2023, but it helped them bond for 2024 and 2025 and produce 6 fledfglings in two years.  I think KZ grew in wisdom and in stature with FAE. 

     I'd like to thank Anna Piccolo for sharp spotting of FAE's remains about a half mile away this morning, and Chuck Carney for helping me track and process two hours of intense activity yesterday afternoon. Also thanks to Frank Killoren and especially Jim Renault for their camera work in helping identify and track discrete individuals this winter. 

     I'll post here any information I receive on FAE's necropsy and tests when I receive it.  

     I will really miss FAE. I hope we'll hear favorable reports on her progeny in the near future. (We spotted a juvenile with a burnt orange Mass band on the lakes last week, but we couldn't read the band.) 

    I hope KZ will rebound and enjoy a successful, productive sixth year on the Mystic Lakes with a new mate. 

 

Best,

Paul      

       

Paul M. Roberts
Medford, MA 
phaw...@comcast.net

[Paula G]

Terrible news.

:(

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[Dan Talbot]

Very sad news, thank you for the detailed and poignant account, Paul.  

On Thu, Mar 12, 2026 at 3:42 PM 'PAUL ROBERTS' via Arlington Birds <arlingt...@googlegroups.com> wrote:

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[PAUL ROBERTS]

I've not heard anything regarding the test/necrospy results for FAE, the adult female Bald Eagle who died on the Mystic Lakes several weeks ago. I will share any news when it is received.

 

Meanwhile, KZ is still paired with Salt, an unbanded eagle apparently about to turn four years old. Salt is so-named because when I first saw her I thought it was FAE standing up in the nest, perhaps making her first nest exchange of the new breeding year. When I saw smudges on the eagle's forehead and behind her eyes, I knew something had happened to FAE. When the new female leaped into the air, I saw her torso but especially her underwings were rife with "salt" marks, white patches obvious when the bird is molting into its "Definitive Basic Plumage."  This bird unmistakably was not FAE.

 

Without top optical equipment or cameras the streaking on the crown and the smudges behind here eye and on the edges of her tail might not be visible at a distance, so she can look like a full adult. However, when you see her underside,  abundant "salt specks" can be obvious in flight in good light. (She will probably lose those salt marks in a year or two.)

    A wonderful article on a Bald Eagle nest in Washington D.C. offers insights into how complex eagles can be, and how each bird can have a distinctive personality, more obvious with growing familiarity. The article should available free from the Washington Post.

    https://www.washingtonpost.com/dc-md-va/2026/03/30/bald-eagle-mr-president-national-arboretum/

 

If you cannot access it, it is available on my Facebook Page, open to all.

    

Meanwhile, KZ's life is in a state of dynamic flux. Almost everything has changed suddenly. His behavior is quite different. I don't like to anthropomorphize "too much" or to think of him as a pet or a human being. He is an amazingly beautiful and complex Bald Eagle, and I would like to better understand his uniqueness as an eagle. I think he really is in mourning. With the exception of the nest, he now rarely perches where he and FAE usually perched. Instead of declaring his ownership of the lakes from THE Eagle tree, he now frequently perches on a tree almost half a mile away, and much farther from public view. Other perches he frequented with FAE he now appears to avoid. He lost his mate and the eggs he thought were imminent, so he doesn't seem to patrol and defend his territory as he did just three weeks ago. Several times juveniles and one-year-olds have physically invaded his nest and he wasn't there to drive them out. In the last day or two, that might be changing, but we shall see.

     

Before FAE passed, one of KZ & FAE's offspring from last year's clutch returned to the Mystic Lakes. 76/C, a juvenile about to turn one, has returned to the lakes and remained in the vicinity. She arrived while the lakes were iced up  and soared over the boat club "bubbler pool" that kept ice from forming near the dock on the upper lake. At least twice KZ aggressively drove 76/C from the limited open water  on the lake. 76/C began perching on THE tree where he saw Mom and Dad perch so often. Several weeks ago, 76/C flew directly to the nest and perched on the 10 o'clock branch, like her mother. KZ saw this and shot down the lake like a bullet. 76/C saw (and probably heard) KZ coming and fled out of the area. Message received. However, 76/C is still fishing and perching in the area, a mid-sized dark juvenile with a dark bib and a dark tawny lower breast and belly, which are about to fade considerably over the next year.

 

Salt has proven to be successful at catching large fish. She and KZ have copulated multiple times and in the last day or two have appeared to pay some attention to the condition of the nest. I think the odds of Salt laying viable eggs are not good, and the odds of any eggs hatching worse. Many eagles, including pairs formed over months instead of two weeks, are not successful in their first year or two of nesting. However, they gain invaluable experience, knowledge, and insight that makes them better parents in future years. And then there are the personalities of individual eagles. (Look at the experiences of First Lady and Lotus.)  

 

Will KZ and Salt remain on the Mystic Lakes? Will Salt really bond with KZ? We can only wait and see. Remember that MK & KZ had a traumatic event in their first nest. They abandoned  that nest and built an entirely  new nest about a half mile away the next winter, stealing that site from a pair of Red-tailed Hawks that had nested there for several years. The first pair of Bald Eagles to "own" the lakes about a decade ago started to build a nest there, but decided to move into a prebuilt home in an old Great Blue Heron nest on Spot Pond. That nest failed the first year, and earlier the second year. The pair apparently "divorced" the third year. (It is not clear if they might have attempted to nest but failed again and separated for good, or if one of the mates didn't return for some reason.)