Report on the 2019 nesting of the White-bellied Sea-Eagles
in the Newington Nature Reserve Forest at Sydney Olympic Park
Summary In the 2019 breeding season, the resident pair of White-bellied Sea-Eagles nested in the
Nature Reserve forest, and 2 eggs were laid. The study again revealed delayed incubation between
the laying of the two eggs. Both young eagles survived to fledge. The second eaglet hatched, SE24,
fledged at 77 days, before its older sibling and survived to be seen hunting on the Parramatta River
and has probably dispersed. The older eaglet SE23 fledged at 82 days but was found dead in its natal
territory at 103 days. In the period of this continuing study, the breeding success has been 45.5%,1
with an average of around one juvenile successfully fledged each season.
Introduction
There has been a Sea-Eagle nest in the Newington Nature Reserve at Sydney Olympic Park by the
Parramatta River for many years, with a succession of eagle pairs renovating a nest in the breeding
season. There are few early records of successful breeding however and several eagles were found
dead. Following the death of a pair of breeding eagles in 2004, necropsy and chemical analysis of
tissues was undertaken in order to determine the cause of death. Further study was recommended.
Their success or failure appears to be closely linked with environmental conditions, particularly the
accumulated Persistent Organic Pesticides in Homebush Bay and the Parramatta River. Nesting
failure has been caused by infertile eggs, sibling rivalry, Beak and Feather Disease, or Trichomoniasis
(see previous reports for more detail).
As in previous years since 2009, the breeding relationships, behaviour and diet of the White-bellied Sea-Eagles were studied using video CCTV cameras and by limited physical observation during daylight hours, from the time of nest renovation to fledging and beyond where possible. In early 2019 a new Research Proposal was submitted and all approvals gained. The Sea-Eagle is listed in NSW as vulnerable under the Biodiversity Conservation Act 2016 and nationally in Environment Protection and Biodiversity Conservation Act 1999 as Marine and Migratory.
Nest renovation
Renovation of the previous nest continued from April, with both eagles bringing sticks and fresh
leaves to renovate the previous nest. The male brought prey items to the nest and mating at or near
the nest was recorded. Duetting was commonly observed, establishing their bond.
Delayed Incubation 2019
The eggs were laid some 73 hours apart. Egg 1 SE23 was laid at 17:37 on June 16. The second egg SE24 was laid at 18:43, on June 19. The first night after egg 1 was laid, when the weather was cold, the female incubated for only 5 hours,
1 Defined a successfully fledged
leaving the egg uncovered for 5.5 hours. As usually it is the female incubating at night, it was unusual to see that the male incubated for over 2 hours, after 3:00am, possibly due to disturbance nearby. The next day, both shared daytime egg duty, with the egg uncovered for over 4 hours. On the second night she again left the egg uncovered, for nearly 6 hours. Graph 1 Number of hours the first egg was uncovered during Incubation before laying of egg 2
Daytime incubation and care at the nest was again shared by both adults. As lay of the second egg approached, incubation time increased until the second egg was laid . Full incubation then continued, with the female on at night, assisted by the male during the day. Graph 2 Daytime Incubation between egg 1 and egg 2
During incubation, the male brought prey to the nest, though not every day. The female brought food a few times, though both probably caught and ate prey elsewhere. Prey brought during this time was mainly fish.
0:00
1:12
2:24
3:36
4:48
6:00
7:12
1 2 3 4 5
NightDay
0:00
1:12
2:24
3:36
4:48
6:00
7:12
8:24
1 2 3 4 5
femaleincubatingmaleincubating
Egg 1 was uncovered nearly 13
hours total at night and nearly 9
hours by day before egg 2 was
laid
During the day, both adults
incubated, with the female a
total of 23 hours and the male
nearly 27 hours
Hatching
The first chick SE23 hatched on July 26, after 40 days incubation.
The second chick SE24 was first seen early in the morning, on the 39th day from lay. Earlier hatching
progress overnight was hidden, as the female brooded in the cold. The two eggs were laid around 73
hours apart and hatched about 33 hours apart, after delayed incubation of the first egg.
Nestling stage
SE23 received food from the female on the first day
after hatching, taking small morsels of whiting from
the female’s beak. Initially the female mainly fed the
chicks at the nest, with the male contributing more
as the chicks progressed. The number of feedings
lessened, as the chicks grew and were able to self-
feed at the nest with prey the parents brought.
Graph 3 Daily Feeding Activity at the nest after hatch
0
2
4
6
8
10
12
14
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82
female feeds young
Male feeds young
Nu
mb
er o
f fe
edin
gs
Days since hatch of SE23 until fledge
Graph 4 Daily Prey Delivery at the nest after hatch until fledge
Initially the male brought most prey to the nest, with the female contributing more as the breeding
progressed. The prey was mostly fish or
birds. Fish included Bream, Whiting and
Leatherjacket and birds- pigeons and
Silver Gulls. A few eels were delivered as
well as left-overs from previous
deliveries. (see Appendix for some prey)
Bird prey was often plucked at the nest.
Silver Gulls were commoner later in the
season.
Sibling Rivalry
Though there was delayed incubation, allowing some “catch up” between the two chicks, there was some initial competition from the bigger, first- laid chick SE23. At times the smaller chick SE24 was submissive and was only fed when the other was satisfied. An interesting observation was when the male brought a bird, possibly pigeon, to the nest on one occasion. He plucked the bird and this bloody prey seemed to stimulate aggression in the bigger chick, SE23. It picked and pulled at the head of its sibling, removing chunks of fluff. A report on nesting Bald Eagles commented that red,
bloody prey seemed to stimulate
aggression in the nest. The normal prey,
0
1
2
3
4
5
6
7
8
9
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82
Female brings prey
Male brings prey
231 fish64 birds4 eels
Days since hatch of SE23 until fledge
SE24 in submissive posture, being aggressively pecked by
its sibling
as for these Sea-Eagles, was fish. 2
As the season progressed, this competition
decreased. The sibling rivalry did not continue as in
the previous year 2018, when competition caused
the death of the smaller chick from lack of food.
Both eaglets gradually began to self-feed, mantling
over prey and eventually feeding themselves from
prey brought to the nest by the parents.
Fledging
As in the past years, as the eaglets grew and developed, they exercised their growing wings, jumping
and flapping in the nest bowl. SE24 branched at just over 10 weeks, flapping to a branch above the
nest and then back to the bowl. It was surprising to see that the younger eaglet SE24 branched
before its sibling and then fledged a few days later at 77 days, taking its first flight away from the
nest, before returning safely some time later. SE23 fledged 3 days after the younger, at 82 days
from hatch.
At the time there was an aggressive magpie near the nest, which swooped the eaglets on the nest.
SE24, newly fledged, was knocked by the magpie and fell to the ground. A circling fox was seen as
the camera was focussed on the fallen eaglet, which defended itself with out-stretched wings.
Fortunately the fox was scared off and the eaglet flapped to safety in a low tree.
After fledging, the adults initially brought prey to
the nest, or fed the young birds elsewhere in the
forest. The eaglets were eventually no longer seen
on the nest.
SE 24 was seen by observers in mangroves on the
Parramatta River, the favourite river roost of the
adults. It was seen taking prey from the adults and
flying strongly over the following weeks.
SE23 was harder to find, though she was
photographed on the ground in the casuarinas forest a week or
so after fledging. Several days later she was found again on the
railway track near the nest. She was seen to fly strongly back
into the forest. However, no definite observations were made
again of SE23 and she was found dead on the disused rail track
at 103 days.
2 page 88, The Bald Eagle Haunts and Habits of a Wilderness Monarch. Jon M. Gerrard and Gary R Bortolotti
SE 24 at the river roost with an adult
SE 24 in submissive posture while the other is fed
SE 23 in the casuarina
forest at 87 days
The dead eaglet was taken to the Taronga Wildlife Hospital for necropsy, which revealed she was
emaciated, the muscle mass was reduced and there were no visible fat deposits. The Pathology
Report summarised “Based on the bird's very poor body condition and the presence of abnormal
ingesta in the ventriculus it seems likely that the animal failed to thrive once fledged”.
SE 23 at 103 days from hatch, showing some feather damage and decomposition
SE24 flying free along the river and roosting on the mangroves. February 2020 Photos :C. Cook
This on-going project contributes to knowledge about and protection of this Vulnerable species. The
project also satisfies activities suggested by the Office of Heritage and Environment to protect the
White-bellied Sea-Eagle:
• Protect known populations and areas of potential habitat from clearing, fragmentation or disturbance.
• Establish 'buffer zones' around nest sites to limit disturbance by humans or human activity. Where nests are located in extensive undisturbed bushland a minimum buffer distance of 500m should be maintained. Where nests are located closer to existing developments a minimum buffer distance of 250m should be maintained, along with an undisturbed corridor at least 100m wide extending from the nest to the nearest foraging grounds.
• Conduct annual, broad surveys to monitor known nest sites, locate new nest sites, determine breeding success and trends in populations, and determine areas of critical habitat.
• Educate the public about the sea-eagle and its status, promote the conservation of the species, and encourage members of the public to report sightings of sea-eagles to the appropriate authorities. (http://www.environment.nsw.gov.au/threatenedspeciesapp/profile.aspx?id=20322)
Acknowledgements The EagleCAM research project team acknowledges the assistance of Sydney Olympic Park Authority
in approving this research and facilitating access to the Nature Reserve and other facilities.
I also acknowledge advice and approval for conducting the activity within Newington Nature Reserve from NSW National Parks and Wildlife Service Cumberland Area Manager and the rangers.
I acknowledge the essential assistance from the EagleCAM team, Geoff Hutchinson, Bob Oomen and Chris Bruce, for camera installation and maintenance and all things technical; Shirley McGregor for managing the live-stream and internet issues: and a wonderful team of volunteers, too numerous to name, for monitoring and keeping observations, managing Facebook and the website and more: and our Supporters, for funding this project.