On their way home

The Little Eagles that breed in the Australian Capital Territory and nearby New South Wales are heading back to their nesting areas. At least two females are back at their previous nest sites and the males are on their way too. Several birds are fitted with GPS-trackers and the project team have been following their movements. 

Y4 (above), a male Little Eagle who has bred in the Canberra area in recent years is on his return from the Northern Territory where he spent the non-breeding season. He spent his time in the area at the northern end of the line in the figure below. He seemed to begin his journey on the 23rd July, then went back north. There was a period of heavy rain then and this might have caused him to go back for a few days. He left again on the 30th July and kept going south.

He overwintered in the same area last year and left on the same date, the 23rd July, taking a very similar route each year. Compare the two routes in the figures. He immediately headed south-east, crossed into northern Queensland, then tracked south over western Queensland. He clipped the north-eastern border of South Australia this year but kept just ouside last year. Then he crossed the border into New South Wales east of Tibooburra and from there headed for Canberra.

It seems that he took a determined direct route home, with no lengthy stops. His northward journeys were less direct and with stoppages. Perhaps he is in more of a hurry when returning to his nest site and partner.

By the time you read this article Y4 will likely be back at his nest site. His partner from previous years is already there waiting for him.

 Little Eagle Migration News

On this World Migratory Bird Day we would like to share an insight gained from the tracking study of Little Eagles that breed in the Australian Capital Territory area.

Part of the Little Eagle Research Group’s aims is to study the birds’ movement ecology. This has been done by fitting a sample of birds with GPS-tracking devices. The study is not yet complete, all the data have not yet been retrieved as there are still birds carrying them. However, preliminary data show that several of the Little Eagles have returned to the same overwintering areas they went to on migration in previous years. Here we give one example, that of a female, Y2, whose migration was featured on this website on 20 September 2020.

This is Y2, the adult female Little Eagle who has repeatedly travelled to the same part of Cape York on migration. She is seen here hunting from a perch in a tree on the edge of the southern suburbs of the ACT. This photograph was taken between her journeys

The previous report showed a map of her route north to and south back from Cape York over the winter of 2020. 

A copy of Y2’s route migration in 2020 as previously shown.

In winter 2021, Y2 followed a very similar route north, and took more or less the same route south. In 2020, she flew farther to the east on the return journey. She took 14 days for her flight on the 2020 southerly flight and 15 days in 2021, travelling at an average of 130 km per day and roosting at night.

Y2’s return flight south in 2021.

The area in Cape York where Y2 has overwintered. The south-eastern edge of the Gulf of Carpentaria is in the top left of the image.

The zone in the above map that is marked in orange is where Y2 spent winter in 2020, 6388 km². The zone marked in purple was where she spent her time in winter 2021, 5366 km². The blue area is 82% of the 2021 area that was within the 2020 area, 4388 km².

In the ACT, the main foods eaten by Little Eagles are rabbits and birds, with a smaller proportion of lizards. There are no rabbits in Cape York. The habitat in the wintering area is savannah where they probably mostly hunt for birds, or lizards and small mammals.

The latest news as of this week: Y2 has flown north again to the same area for a third winter.

The route followed by by Y2 this year was similar to those in the previous two years. 

In 2020 she left the ACT on 14 March and took 10 days to reach her overwintering area, in 2021 she left on 26 March and took 9 days. In 2022 she left on 16 April, and took longer, 18 days. It is possible that weather might influence the timing or the birds' migration and further analysis of this is ongoing.

World Migratory Bird Day is an annual awareness-raising campaign highlighting the need for the conservation of migratory birds and their habitats. It is a global outreach and is an effective tool to help raise global awareness of the threats faced by migratory birds, their ecological importance, and the need for international cooperation to conserve them. This is a  United Nations Environment Programme.

 Feeding a fledgling

The Little Eagle fledglings are becoming a bit more independent now. Today, this one was calling to its parents whenever it saw them, begging for food. However, food delivery is slowing. While passing the time, this bird was seen to dive at potential prey on the forest floor, small  birds mostly from what I could see through the foliage. The eagle was quite happy to sit quietly up on a high branch while people walked past below, then it would stoop straight off its perch and try for a kill. Like so many kills I have seen, the points of impact, or possible impact, was just out of view. The last attack was actually towards me as I sat quietly below, and the eagle missed a Crimson Rosella on the edge of the path fifty metres from me.

The young bird was well aware of my presence, and it was relaxed enough to hunt while I sat about 100 m away. It is so used to people walking past and below its nest and surrounding trees - bush-walking is a very popular pastime in Canberra. This is probably the darkest young Little Eagle I have seen. There is barely a hint of juvenile red plumage, a touch on its legs, and even the red on the head is dark. 

The fledgling was still being fed though. The adult female brought in this juvenile Crimson Rosella and the two eagles began calling repeatedly to one another, the fledgling being particularly excited at the prospect of breakfast.  

The adult began plucking the rosella and I was waiting for her to carry it over to the fledgling. But, not so quick. She started to eat the rosella, from the head down, and did not show any intention of giving it to her youngster.

 

About forty minutes later, she did fly over to the fledgling with the lower half of the rosella. Yet, still she did not hand it over. She sat on a branch next to the young bird's branch and ate a little bit more, while the fledgling jumped to and fro between the branches, as if wanting to snatch the food, but wary. There was a pecking order, and the young bird was only given the food once the parent had eaten her share.