Study Information about Sydney Olympic Park

White-bellied Sea-Eagles - 2014

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Birdlife Australia - Southern NSW Research Team, Judy Harrington, Geoff Hutchinson, Jon Irvine.
Thank you to our data collectors for their valuable contribution towards this ongoing research. Dasha Ostby, Marsha Baden, Cathy Cook & Pat Burke.
Also thanks to the operations team, Shirley McGregor, Melanie Pittard, Helen Stibbs, Ben Kirtland and Faith McGregor.

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The year started with the Sea-Eagles doing some interesting out-of-breeding-season behaviour that the research team had not observed before. The Eagles were visiting the 2013 nest (nest #2) about every two weeks, not bringing sticks but just rearranging the material that was there. The first stick delivered to the nest was observed in early April 2014.

The EagleCAM team removed the cameras from the 2013 (nest #2) tree to undertake maintenance and upgrades. To continue monitoring the movements of the Eagles they installed a camera on a tripod at ground level.

By the end of April the research team noticed that the visits by the adult Sea-Eagles to the nest had ceased. There was one visit by a juvenile Sea-Eagle perching above the nest in late April. They started to investigate the possibility of the Sea-Eagles building a new nest within the Reserve. It took three searches over a number of weeks to locate the new nest about 75 metres from the nest #2 tree. This new nest was being constructed in an Iron Bark tree, unlike all the previous nests, which were in smooth-barked trees (Blackbutt & Scribbly Gum). The nest was fairly well advanced so we monitored the activity for a few weeks with the ground camera and the decision was that the Sea-Eagles were committed to this new nest.
In mid-May the team installed the cameras, ready and hoping for a good season. About 120 metres from the new nest is the Armory train storage shed, in late May work had just commenced to replace the asbestos roof, with many trucks and cranes. Workers removing the old roof and installing a new one. This may have influenced the Sea-Eagles to abandon the new nest (nest #3) and return to the (nest #2) where they continued their renovations. In early June we installed a ground camera to monitor their activity at nest #2 (2013 nest).

After many weeks of watching both nests it was decided in mid-June that the camera should be moved from nest #3 and installed on the nest #2 (2013) tree.
This was achieved with little disturbance to the Sea-Eagles, they returned to the nest after a few hours and were observed mating a short time later.
The visits to the nest by the Sea-Eagles increased up to 20 times per day, the male bringing sticks and food for the female. The female bringing leaves.

The first egg (SE-13): was laid on 4 July 2014 at 5:28 pm.

The second egg (SE-14): was laid on 7 July 2014 at 10:56 pm. About 77.5 hours after the first.

The first pip of the shell of SE-13 was seen at about 4:50 pm on 12 August 2014 and SE-13 finally emerged out of the shell at 6:17 pm on 13 August 2014. That was about a 25 hour struggle. The first feed for SE-13 was at 12:12 pm on 14 August.
After about 42 days from SE-14 being laid it was presumed that the egg would not hatch.
At about three weeks of age, it was noticed by the Internet Live Stream viewers that SE-13 was having problems with swallowing food. Everyone kept monitoring progress closely but it was clear SE-13 was having difficulties. On 12 September 2014 at 30 days old, SE-13 sadly died on the nest.
Permission was sought from Sydney Olympic Park Authority and National Parks & Wildlife to remove SE-13’s body for testing, this was granted and was removed from the nest on 13 September 2014.
For the 30 days that SE-13 was alive, 20 of those days were raining. There was only one period with two days in a row that it did not rain.
SE-13’s body was taken to the Animal Referral Hospital where a necropsy was conducted and it was found that SE-13 had very advanced lesions in the throat consistent with Trichomoniasis also known as ‘Frounce’ or ‘Canker’. This disease could have been caught from consuming a pigeon, which is a common carrier of this disease, and a common food source for young Sea-Eagle chicks.
The second egg SE-14 was X-Rayed and it showed bone and feather of an approximately half developed embryo. It is not known why development ceased.

SE-14 egg          X-Ray Table          X-Ray of the Egg
SE-14 egg                                           X-Ray Table                                 X-Ray of SE-14 Egg

White-bellied Sea-Eagle chick (SE-13) died prematurely on the nest on the afternoon of 12 September 2014 at the age of 30 days. The body was recovered from the nest on the morning of 13 September 2014 and was transported to the Animal Referral Hospital (ARH) at Homebush NSW for a necropsy.

Observations prior to SE-13 Death

Observations were conducted utilising a 1080P High Definition Pan, Tilt, Zoom (PTZ) Video Camera with remote access to control the camera. All the video was archived and an operator controlling the camera was on duty at all times.
SE-13 hatched on the afternoon of 13 August 2014. The adult eagles had supplied a variety of food in preparation for the arrival of the first chick. The first food that was fed to the chick was Feral Pigeon, delivered to the nest plucked and with the head removed. Over the next four weeks there was a variety of food supplied to the nest including pigeon, fish, eel, blue-tongue lizard, frog and water fowl. Fish being the main food supplied, there was also 12 birds delivered to the nest over the 30 days and at least six of these were pigeon. Three were water fowl and some were not able to be identified. Over the first three weeks the chick appeared to be thriving as would have been expected.
On 6 September 2014 the first report of the chick having some issues swallowing food was received from one of the viewers. When feeding, the chick was holding its head back to try to swallow and then shaking its head violently from side to side appearing to be trying to dislodge the food that was stuck in its throat. After the death a review of archived video showed that the chick was starting to struggle as far back as 30 August 2014 but this was not identified at the time by any of the hundreds of viewers watching the live stream.

After being notified of the chick’s problem, the high-powered zoom function of the high definition (HD) camera was used to have a closer look at the chick’s mouth and tongue.There was no obvious problems seen on the tongue or mouth.
In the week prior to death it was also observed that the chick was having problems opening its left eye. In the months of August and September for the duration of the chick’s 30 days of life there were 20 days of rain. There was only one period of two days that there was no rain.

Necropsy Results                Observations notes by Geoff Hutchinson who attended the Necropsy.

The body of SE-13 arrived at the Animal Referral Hospital (ARH) on the morning of 13 September 2014. On first inspection of the body it was observed that it was extremely thin. It was first X-rayed in three different positions. The results showed there was no immediately visible foreign objects within the body.

X-Ray of the SE-13        X-Ray of the SE-13        X-Ray of the SE-13
X-Ray of SE-13

The body cavity was opened to inspect the internal organs. All organs appeared to be in healthy condition, including the heart, liver, kidneys and lungs. The gizzard was opened to reveal the contents, there was a mass of feathers completely filling the cavity. The small intestine and the rectum looked normal with no blockage.
It was observed that there was a hard swelling at the base of the skull and extending about 35mm down the neck. An incision was made from the gape down the neck. This revealed large granulomatous lesions that occluded the oesophagus. The lesions were not present in the mouth or on the tongue.
The lesions extended approximately 35mm down the oesophagus from the throat. At its lower section the lesions were about 8mm thick. The constriction of the oesophagus was down to about 5mm in diameter, completely inhibiting the swallowing of food and the regurgitating of pellets.

SE-13 swolln throat        Trichomonas lesions        Trichomonas lesions
SE-13 swollen throat                                 Trichomonas lesions                                 Trichomonas lesions

 

Conclusion

The results of the necropsy revealed the presence of a large granulomatous lesion that occluded the oesophagus so much that it would have inhibited the consumption of food apart for the smallest morsel less than 5mm in diameter. This lesion would also be compromising the trachea and affecting respiration. After reviewing the archived video from the previous three weeks it became apparent that the SE-13 was not getting the amount of food that would have been expected. This lack of food intake would have reduced the intake of moisture resulting in it becoming increasingly dehydrated and an overall loss in body weight.
With the contents of the Gizzard being all feathers, which would normally be regurgitated as a pellet. For SE-13 this would have been impossible due to the restriction in the throat.
The lesions in the throat and oesophagus being hard, creamy/white granulomatous lesions had the appearance of those caused by the Trichomonas protozoal parasite, causing the disease Trichomoniasis. This is a common disease carried in pigeons in the wild. If the chick was under some type of stress, such as extremely wet cold conditions and the chick consumes something sharp or abrasive and compromises the tissue of the throat, the Trichomonas protozoal parasite can infect the tissue.
The death of Sea-Eagle chick SE-13 was most likely due to an unfortunate set of natural circumstances that compounded into the final outcome. The constant rain was possibly a major contributing factor putting the chick under stress. The supply of birds as food, especially pigeon, would normally not be a concern without the other influences.

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