Background & Updates on the Tesoro Eagles

The eagle pair residing on the Tesoro property have been residents of St Lucie County longer than many of the human residents. Their territory was first recorded by the Florida Fish and Wildlife Conservation Commission as SL001 in 1978 and is the oldest documented nest in the county. There is no guarantee that this is the original pair, but since bald eagles mate for life and can live for over 30 years in the wild, chances are good these are the same birds. Florida’s eagles spend the fall and winter raising their young, then leave the nest territory in the spring after the eaglets have fledged. They typically spend the summer apart, and then return to the same nest each fall to reestablish their pair bond and begin the nesting process again. The official nesting season in Florida is October 1st-May 15th. The Tesoro eagles are among the earliest to return to their nest site, with one of the pair arriving last year on August 20th.

The nest territory is the area approximately one mile in diameter that the eagles call home and will defend. It is not unusual for them to relocate within the territory, and this pair has moved four times since they built their first nest. One of the reasons for a move may be that great horned owls decide to take over the eagle nest for their own use. Eagles will not argue, for the owls, though smaller, are stronger and much more aggressive. The SL001 eagles were smart enough to relocate when owls decided to move in during the 2003-04 nesting season. Last season, with video cameras in place and a website dedicated to the eagles ready for viewing, Hurricane Wilma snapped the camera tree and damaged the nest tree. Luckily, the eagles had already begun constructing an alternate nest to the north, and they successfully fledged two young in the spring of 2006.

Fall of 2006 brought the eagle pair back to their nest, and once again there was hope that they would be successful. Nest refurbishing, mating and egg-laying were observed by eagle cam viewers. Unfortunately, the eggs were not fertile, and after incubating the eggs for two months, twice as long as necessary for fertile eggs to hatch, the eagles finally abandoned the nest.

This season, the third, had to be the charm, or so we hoped. Once again, the unforeseen intervened and we were afraid there would be no eagle viewing this season. This pair of eagles is even more nomadic than most, and they relocated to the other side of the lake. They began building a new nest in a live pine, a step up from the dead tree the previous nest occupied.

The generous donation of a large conservation easement by Ginn to Audubon ensures that the eagles have quality nesting habitat, so it was not totally unexpected for them to move.

Being eagles, however, they can change their minds! They have now stopped work on the new nest and moved back to the dead tree within view of the camera. They began incubating on December 7th, with a hatch date on or about January 9th.

Please contact Lynda White if you have questions about this pair or bald eagles in general.
Date Description Picture
     
6/3/08

Birdie is on the move, and as of May 31st she was located north of Cape Canaveral on Florida's east coast. This is over 100 miles from Port St. Lucie, and signifies that she has dispersed from her natal territory. Though we have no way of tracking her sibling, it is likely that Bogey is also moving away from the nest territory. The latest satellite data shows Birdie spending some time around Lake Tohopekaliga in Osceola County, south of Orlando. While there she likely came into contact with some of the eagles inhabiting the densest concentration of nesting bald eagles in the world.

It is time to turn off the camera view. Hopefully the nest tree will survive Florida's summer storms and the adults will return in the fall. Tune in again in a few months as the eagles share their nesting season with viewers worldwide.
5/23/08 Seven weeks after their first flight, Birdie and Bogey are infrequent visitors to their nest. Birdie's transmitter data shows her flying to the coast several times and ranging over the Ginn property in all directions. It may take several more months before they decide to disperse from their natal territory, and one or both may show up at the nest after the adults return in the fall. If they do, food begging and whining will get them nowhere, for their parents will be preoccupied with a new nesting season. The adults will ignore their offspring and may even chase them away if necessary.
4/23/08

The fledglings are learning to survive on their own, and visits to the nest are becoming more infrequent. As they get their bearings they will gradually expand their range. Thanks to Birdie's transmitter, we will be able to track her movements.

The nest tree continues to deteriorate, with a large limb falling into the nest last week. This tree may not survive the summer's storms, but the eagle pair have plenty of trees to choose from on their 120 acre conservation easement. Eagles are site-faithful, and as long as there is suitable nesting habitat they will return to the territory.
4/9/08 The fledglings are busy exploring their new world but continue to return to the nest every day. The adults fly in with food, and even feed the hungry youngsters a morsel or two before taking off. Birdie and Bogey should begin hunting on their own, but they know a meal is always available at their nest, allowing them to survive as they learn to be eagles.
4/2/08 The first of the eaglets left the nest on April 1, 2008, when Birdie flew to a snag near the nest tree. She perched for over two hours, then flew away. Bogey remained in the nest except for very short hops back and forth. This morning a transmission from the satellite transmitter (see photo page) located Birdie not far from the nest. Bogey flew today as well, and both have returned to the nest.

This is normal behavior for fledglings, and there is no reason to panic if the birds do not return to the nest for a day or two. As they become more proficient at hunting and foraging they will spend less and less time at the nest.
3/26/08 It won't be long now before the eaglets take their first flight. Bogey, the smaller eaglet, is more adventurous than Birdie, his larger female sibling. He is spending more time perched on the branch above the nest. Branching is the final step before the first attempt at flying, and it could be any day now.

Fledglings typically return to the nest for a few days or even weeks before they take off on their own. They spend some time with the adults, picking up some hunting and fishing tips, but much of what they need to know to survive is instinctive. As long as they return to the nest and food beg, the adults will continue to feed them.
3/17/08 Birdie and Bogey are spending more time jumping and hovering in preparation for their first flight. Now nine weeks old, they are as large as their parents. In just over two months their weight has increased from four ounces at hatching to six to eight pounds today.

They are feeding themselves now, but when the adults fly in with food they spend a few minutes feeding the eaglets before they leave.
3/13/08 The piece scheduled to air last night on NBC Nightly News regarding Bobby Ginn, Tesoro’s eagles and Ginn's partnership with Audubon and the Institute of Wildlife Sciences was preempted. It has been rescheduled, barring any major new news events, for tonight. It will be the show closer.
3/12/08 A story is scheduled to air tonight on NBC Nightly News regarding Bobby Ginn, Tesoro’s eagles and Ginn's partnership with Audubon and the Institute of Wildlife Sciences. It will be the last story in the newscast.
3/4/08 Banding of the eaglets went perfectly yesterday, as they were removed from the nest, examined, then fitted with bands.

The larger eaglet was also fitted with a solar powered satellite transmitter. The device weighs 50 grams, about 1/10th of a pound, and she is already accustomed to it. It is easily visible now, but in time, as she preens, it will disappear under layers of feathers with just the antenna showing. When she is full grown she will weigh about 10 pounds, so this device will be just a fraction of her total weight. It is designed to fall off in 2-5 years.

The eaglets' exam found them to be in excellent health with good weight and perfect new plumage. They are well on their way to fledging in 3-5 weeks. The adults were remarkably calm as we worked, showing no alarm or distress, just circling overhead to keep an eye on the proceedings. One of the adults was back at the nest with food within minutes after the eaglets were returned.
2/25/08 The eaglets are rapidly exchanging their down for dark brown feathers as they continue to grow at an astonishing rate. They are feeding themselves from prey left at the nest, and the adults continue to feed them as well. Frequency of feeding has increased, keeping the parents busy bringing in food.

A large bulge on the eaglets' chests is often visible. This is the crop, part of the esophagus where undigested food is stored. Adult eagles can carry up to two pounds in their crop, allowing them to gorge themselves when food is abundant and survive when they cannot find suitable prey.

Banding of the eaglets is scheduled for March 3rd, depending on the weather. The youngsters will be handled gently and returned to the nest as soon as possible. The parents will return and all will be back to normal. Birds live in the moment, and since these eaglets have spent weeks with their parents, there is no chance this brief encounter with humans will have an adverse effect on their ability to survive in the wild.
02/24/08 The eaglets continue to grow at an astonishing rate, with their weight increasing from four ounces at hatching to four to five pounds in just six weeks. They are beginning to help themselves to food left in the nest, but the adults continue to feed them as well. Frequency of feeding has increased, and the parents are kept busy bringing fish and other prey to the eaglets. Their true feathers are beginning to cover their bodies, and the long flight feathers on the wings and tails are becoming noticeable.

If the weather cooperates, the eaglets will be removed from their nest on March 3rd. The researchers will work quickly to band and examine the youngsters and return them to the nest. Birds live in the moment, and this brief intrusion into their lives by humans will have no adverse impact on their ability to function as wild eagles. The adults will keep a wary eye on the proceedings, and will return to their eaglets when we have returned them home.
02/14/08 If you look carefully, you can now see true feathers forming on the wings and tails of the eaglets. The older one has lost most of his fluffy natal down, and the younger one is rapidly catching up in size. They are beginning to peck at food in the nest, but the adults are still feeding them several times a day. This is the only time in their lives when they grow all their feathers at one time, and they are expending a tremendous amount of energy in feather, tissue and muscle growth.

When the eaglets are approximately six weeks old we are going to remove them briefly from their nest, take blood samples and perform a physical exam to ensure they are healthy. We will also be able to determine their sex. Both of the birds will have a USFWS band attached to a leg, and one of them will be fitted with a satellite transmitter. When the eaglets fledge at 10-12 weeks of age, we will be able to track the fledgling as he leaves Florida and migrates north for the summer, then home in the fall. This will provide valuable data as we continue to learn about the migratory patterns of Florida's bald eagles. The viewing public will be able to follow the fledgling's journey online as we receive transmittals from the device.
2/5/08 Now approaching four weeks of age, the eaglets continue to grow at an astonishing rate.Though one is larger than the other, the size difference will diminish as the younger chick catches up to his older sibling. Most of the time, in a two-eaglet nest, one is male and one female. At six weeks we should notice that one is growing larger; that will be the female.

The eaglets are much more active, and have begun to playfully peck at each other and play with nest material. The parents occasionally leave the nest for short periods, but one is always nearby to protect the youngsters. They are consuming more and more food every day, so the adults are kept busy bringing fish, squirrels, snakes and wading birds, among other prey, to the nest.
01/24/08 Two downy eaglets are now clearly visible. They are two weeks old, and their light gray natal down is being replaced with darker woolly down. They can now thermoregulate their body temperature, and the adults no longer have to keep them warm. The parents may occasionally leave the nest for a few minutes, and this is no cause for alarm. One of the pair is always nearby to protect the youngsters. They are still spending much of their time sleeping, but will become more active in the coming weeks. The rate of growth, fastest of any North American bird, is amazing. In another eight weeks, these small birds will be as large as their parents.
01/14/08 It appears that at least one eaglet hatched between January 9-11. Feeding behavior has been observed, though the eaglet(s) are too small to be seen immediately. They weigh only four ounces at hatching, are about five inches tall, and are covered with light gray natal down. They are semi-altricial; their eyes are open but they are completely dependent on their parents. The adults will bring in food and offer small pieces of soft organ meat for the first few days.
2007
12/4/07 The eagle pair have changed their minds once again about their choice of nesting sites for this season! They have stopped work on their new nest in a live pine and moved back across the lake to the dead tree in view of the camera. Since this pair typically lays their eggs in early to mid December, we suspect this is the last move of the season, and they will stay put. Please enjoy the live streaming video and the eagle's eye view of the birds incubating their eggs and hopefully raising an eaglet-or three!
3/12/07 The adults have stopped incubating the infertile eggs and have not been seen at the nest recently. It is unlikely that they will lay a new clutch this late in the season, but it's not impossible. The camera will remain on for viewing, and we are still hopeful for a successful season for this pair.
2/23/07 So far we have seen no evidence of a new clutch. The adults are spending more time away from the nest, so we are hopeful that they have given up on the infertile eggs and will concentrate on a new attempt.
1/31/07 Yesterday, the 54th day of incubation of their infertile eggs, the eagle pair were observed copulating. This is a hopeful sign that they will lay another clutch of eggs and have a successful season.
1/23/07 The eagles are continuing to incubate their infertile eggs. It has been 47 days since they began incubating, and hopefully they will give up soon. We will look for copulation when incubation stops, and hopefully a new clutch will be laid. Stay tuned!
1/16/07 The eagles began incubating December 7th, which meant an anticipated hatch date around January 9th. Unfortunately, the eggs have not hatched, meaning they were probably infertile. It is early in the season, so it is possible they may reclutch and try again.
1/02/07 The eagle pair continue to share incubating duties, exchanging places at the nest every few hours. They can be seen turning the egg(s) with their beaks, then settling down into the nest. Hatching is expected on or about January 9th.
2006
12/08/06 The female eagle was in incubating posture yesterday morning. When the the male flew in a few hours later and relieved her (nest exchange), it was confirmed that an egg has been laid. There are typically two eggs in a bald eagle clutch, but it can be two to four days before the next egg is laid. Incubation will last 33-35 days, so we can expect an eaglet the second week of January. A brood or incubation patch has developed on the abdomen of both of the adults to aid in keeping the eggs warm. This patch is an area of bare skin and increased vascular circulation- a built-in "heating pad". The adult on the nest will turn the egg(s) about once every hour to ensure even warmth and proper development of the embryo.
11/20/06 The eagles are spending more time at the nest, and they have been observed copulating. The mating act occurs after the female indicates she is ready, and the male climbs on her back with talons folded under to protect her. Their tails are turned so the cloacae can meet, and the entire process takes five to fifteen seconds. As the time for egg-laying grows closer, the frequency of copulation will increase. They are continuing to bring in sticks and rearranging the nest to their liking.
9/13/06 Both of the eagles have returned to the nest site! They have been spotted early in the morning and in the late afternoon, typical behavior for a pair before they begin actual nesting. Yesterday the male was seen flying in twice with nest material, and the female spent some time rearranging sticks inside the nest. Since the nest survived the summer’s storms, it just needs some refurbishing before it is ready for use.
8/27/06 Two state of the art video cameras were installed in a slash pine adjacent to the Tesoro eagles' nest tree (SL001D) in August. The cameras will provide a birds' eye view of the nesting activity of the resident pair, from courtship and mating to egg-laying and raising the eaglets to fledging.