By Bernheim
April 6, 2019
Harper and Athena left Bernheim on March 11, 2019 and flew 1700 miles on separate paths. The morning of April 6, 2019, the eagles roosted 26 miles apart in northern Manitoba. At 10 a.m., they both left their individual sites and started flying directly together, reuniting at their destination by flying in from opposite directions within 2 hours of each other. Within 1 hour of their rendezvous, they flew together to the location where Harper spent most of his time in summer 2018, which we presume to have been a nest location.
April 7, 2019
Athena stayed at the nest, making short trips around the surrounding woods. Harper flew off towards Churchill River and Hudson Bay, visiting his old haunts on the Churchill River and coastal areas on the Hudson Bay as we had seen him do in previous years. Harper spent the night on an exposed windswept point looking out at the sea. Both the sea and the land were completely frozen as the low temperature that night was -15 F, but the northern lights display looking north across the Hudson Bay was probably spectacular. Why he would travel so far to spend one night on this frozen seaside location is a mystery, but we know he has made this pilgrimage to the Hudson Bay in each of the three years he was tracked. This is intriguing to me – such a long trip shortly after migration must have an importance we cannot yet interpret.
April 8, 2019
Harper headed back towards Athena who was still at the nest. His flight took him back the 30 miles to another lake, located 3.5 miles away from the nest site. As soon as he lands at that lake, Athena took off towards Harper, where the pair reunited at another nest site. This site would eventually become a central location for the pair over the 2019 breeding season.
Golden eagle nests are called eyries, and in this situation, they appear to be in trees. There are not many large trees on this interface between tundra, exposed rock, and boreal forest, so choice nest sites may be long used and restored every year. Golden eagles will typically have more than one eyrie, and with this pair we see the golden eagles preparing two sites, with a possible third location (which may have been a historic nest) that they visited several times.
Harper left the new eyrie location and traveled six miles south to another lake, where he spent the next the day among wooded cover between lakes.
April 9, 2019
Athena made short trips back and forth in a 400-meter area around this new eyrie, likely collecting materials to build or restore the existing nest. It is typical for golden eagles to have several nest locations and it seemed they were restoring or preparing two sites. With both golden eagles reunited and readying two nest sites, it looked as though they were off to a good start for the 2019 breeding season. Athena then took off to fly back to the old eyrie location.
April 10, 2019
Harper and Athena linked up at the old nest again after several days apart and roost there together.
April 11, 2019
Both eagles made trips from the nest, traveling around the area. It did not appear that any eggs had yet been laid, as both eagles were away from the nest for a considerable amount of time.
April 12, 2019
Harper and Athena traveled to the previously visited third nest option. They spent four hours around the site, presumably working on securing the spot. This is a best guess, as it looks favorable in imagery and seems to be a location they put some effort into. It may be a historic eyrie they defend, or it is possible it is just a preferred hunting location they both frequent.
April 13- 21, 2019
Athena stayed at the old nest and did not leave the site for ten days. It falsely appears she had settled on a nest.
April 22, 2019
Athena abandoned the old nest, flying back to the other site. Harper joined her there and continued traveling widely, presumably hunting and bringing food provisions back to the new nest site. This behavior is clearly demonstrated in our data, with Athena now settled on this location for her final spot. The eagles had now spent 2 weeks preparing the eyries and chose the final location. For next six weeks, Athena spent most of her time at the nest as Harper traveled widely between lakes providing food.
April 22-24, 2019
Data suggests Athena laid eggs, likely two or three, during this time period.
April 25, 2019
Our first big indication an egg had been laid! Athena left the nest while Harper stayed in her place. Athena was gone for nearly 3 hours visiting both other eyries. After this time, at least one eagle was on nest at all times, indicating that they were incubating eggs.
April 28 2019
Athena left the nest to visit other eyries but only stayed away for one hour. Again, Harper stayed at the nest while she was away. Athena seemed to be checking the other sites to make sure they were still viable options if needed. Harper also visited the other nest sites regularly, seeming to stop to hunt or just checking on the structure.
Another possible reason for his visits is that they must defend the other eyrie from other golden eagles that would want to move into territory. Because these eyries are long used across generations, there is likely competition for these favored sites from other golden eagle pairs and territorial battles occurring that our data cannot reveal.
We know the lakes were still frozen and ground covered in snow, as temperatures averaged only 17˚ F for the month of April. It is uncertain what food sources were being used, but a clearer picture now emerges of how these golden eagles cooperated during the beginning of nesting season. We can assume they were not feeding on the waterfowl yet, as they would not arrive for several more weeks after the lakes began to thaw.
Our data clearly reveals Athena and Harper were making an attempt at nesting during April. The golden eagle pair worked hard for three weeks on two main eyries to increase the likelihood of success, but only one site could be chosen for the incubation period which usually involves laying and sitting on 2-3 eggs. It now seems certain that 2019’s nesting site was different from Harper’s 2018 presumed nesting location.
Athena sat on the nest continually, while Harper continued to hunt. Harper began to provide Athena short breaks for flights, usually occurring between 2 – 3 p.m., but not every day. I would expect that the frequency of these breaks might depend on weather and other factors such as nearby presence of predators.
May 1, 2019
Temperatures were still very cold, with an average for the month of May just 30.1˚ F and average winds of 13.2 mph. The landscape still frozen, Harper and Athena divided their time between the two main tasks of food procurement and care of the eggs. Athena spent all of her time on the nest, while Harper foraged and made returns to the nest presumably to feed Athena.
May 4, 2019
After 6 days on the nest, Athena took a 1-hour flight while Harper sat on the nest, but she only traveled 1 mile out across the lake and could always see and hear Harper on the nest. She was showing to be extremely dedicated to the incubation process. With it being just 28˚ F on May 4, it seems that extreme weather conditions and likely snowfall would make the task of continual incubation difficult.
May 6, 2019
Harper again relieved Athena for a flight from 1:30 -3 p.m. That night, he stayed away at the south eyrie. Data showed that Harper stayed at the old nest site several nights during May. The reason is uncertain, but could include territorial defense of old nest or use of the site as preferred hunting location.
May 11,, 2019
Both eagles were briefly away from the nest, but Harper quickly headed back after encountering Athena several miles south of nest in what looks like communication between the pair. She returned later and all seemed well, and she may have squawked at him a bit. The communication between golden eagles, particularly distress calls as observed between Athena and Harper at Bernheim, are what you might imagine a pterodactyl to sound like.
May 14, 2019
Athena visited the old nest site in the morning and spent 2.5 hours away from 7:30-10 a.m. This is the earliest and longest she left the nest during the incubation period. As usual, Harper stayed on the nest while she was gone.
May 17, 2019
Athena was still on the nest and Harper was traveling and hunting. He made regular returns to the nest but continued to occasionally stay out all night, either at the old nest site or other locations. He moved around some during the night as the sunlight continues to lengthen. In northern Manitoba, there is very little darkness in summer, and occasional night movements by Harper may be explained by longer days for hunting or other activity.
No big changes occurred during the following few weeks, which was good. Finally . . .
BIG NEWS!!!!!
June 3, 2019
Athena stayed at the nest for the next 6 days. It appears from her staying at the nest during this long stretch that this is the period when the egg(s) successfully hatched. Incubation is presumed to last 42-45 days, and if these eggs were laid on April 22, they would hatch approximately 6 weeks later during the week of June 2.
Hatching is a special event, and while we don’t know how many eggs hatched, we can confirm from our data that the golden eagles produced at least one chick in 2019. They had been working hard for 7 weeks to repair and build two eyries, lay and incubate eggs, feed both adult eagles, and defend the nest from other golden eagles and possibly other predators. Hatching then began with chirps from the egg as much as 37 hours before fully emerging from the shell. During the first few days, eagle chicks have a dense covering of greyish down, then turning snow-white by 6 days.
June 9, 2019
Athena spent nearly all her time on the nest. This is the brooding period, which involves covering and sheltering the young. Brooding is a near constant necessity for the first 20 days. The mother eagle provides warmth from the cold and shelters the nestlings from the heat of direct sunlight. Heat is a serious threat to nestlings, and may have been an issue on June 18-19 when temperatures reached 81˚ F. The chicks must also be shielded from any rain, snow, or marauding predators that would dare raid a golden eagle’s nest. Athena made a short flight, 9:45-10:30 a.m. while Harper guarded the nest. This pattern continued throughout June.
Feeding is a two-eagle job. Harper spent nearly all his time hunting, increasing the quantities of presumed waterfowl for the mother and nestling(s). June’s warmer temperatures thaw the landscape, bringing astounding numbers of migratory waterfowl to nest on these shared Canadian lakes.
The mother eagle must tear up food for the chicks until they are almost a month old. The nest becomes a messy place with eaglets creating pellets, carcasses piling up, chicks defecating in the nest, and constant activity between chicks and parents. Greenery has been documented as being added to nests during this period to cover debris or possibly repel parasites.
July 1, 2019
Now approximately 25 days old, the chick(s) have primary, secondary, and tail feathers emerging. They are standing and feeding themselves, and we see that Athena’s behavior began to change. She took longer trips while Harper waited at the nest. This behavior is likely a signal that Athena was ready to get back to hunting and spending some time away from the nest.
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