A pair of white-bellied sea eagles have taken a liking to a towering tree that borders the Austinmer backyard of Casey Holdsworth and her family.

With wings spanning about two metres, the creatures are a sight to behold in full flight, with several residents recently reporting their wonderment at seeing one overhead with a freshly caught fish in its talons.

For Ms Holdsworth, who has four small dogs, the amazement has worn off somewhat.

She is keeping her dogs - a Moodle, Cavoodle, Maltese Terrier and Shih Tzu - indoors around the clock, out of fear they will be snatched from above.

"Every day we're locking them inside now, all day," she told the Mercury.

"The moodle is only 6kgs - he could easily be picked up. The eagles are bigger than him.

"They're huge and they're constantly looking down here. They are constantly flying off and coming back, flying off and coming back.

"To think that something could fly down from the sky and steal my dogs - that would be a horrible way to go."

Ms Holdsworth recently took to social media to warn residents about the birds, noting she had heard stories of them seizing rabbits and small dogs.

She told the Mercury her family had lived at the address for five years and not noticed the eagles until recently. She wonders if her noisiest dog - the Shih Tzu - caught their attention.

Sea eagles typically start laying eggs in June/July and spend the months leading up to that building nests and establishing territories.

Sea eagle expert Dr Rohan Bilney said the birds didn't like disturbance around their nests, and would typically build them several hundred metres into the bush. But to feed, they would be content to set up in a noisier environ - like the backyard of a yapping dog.

"Eagles do like perching on prominent trees where they can scout for anything or even sit there, digesting."

Shown the above picture of the birds, Dr Bilney noted they had "full crops" - fulsome mounds between their throats and stomachs - indicating they had recently fed well.

He said the creatures favoured fish and roadkill but that small dogs such as Ms Holdsworth's could also be on the menu.

"They're pretty easy pickings, probably."

Dr Bilney said pairs of the birds were spaced about 2-3kms apart along the far South Coast, where he has recorded about 100 nests as part of an ongoing study. They are sparser on the urban fringes and at this time of year, outside of breeding season, there were a lot more of the birds roaming further afield to mingle and find a breeding territory.

He said the bigger of the pictured pair was a female, with plumage suggesting it was an immature bird, aged about three years. He said it was quite possible that two birds would soon become three.

"It's highly speculative, but if you're seeing the birds together on a regular basis, and they're going through various courtship behaviours, then that's indicative that they are a pair. I'd say they're heading into their first breeding year."

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