If crow-like birds had dared to land at Hamilton Lake several decades ago, James Williamson may have been laying in wait with his bow and arrow.
The ex-hunter and Melville resident spotted rook birds - a crop pest - at Innes Common this week during one of his walks around the lake.
"They fly in and they go ‘kaah kaah kaah kaah', you know, and they sit in that gum tree up there."
It's the first time he'd seen rooks in Hamilton and feared the birds would spread and become a problem for nearby farmers and their crops.
Williamson spent many years hunting possums and wallabies with a bow and arrow, and was the first New Zealander to shoot a Himalayan bull tahr mountain goat unaided in 1964 at Lake Tekapo. Its mounted head still hangs in his home.
Now nearly 70, Williamson said his days of hunting pests were behind him, but was concerned at the presence of the pests.
"[Council] are going to have enough trouble with these geese around the lake."
Waikato Regional Council biodiversity officer Paul Quinn said council has been tracking the movement of rooks in the area for the past several years.
"There have been about six rooks living in Hamilton city for the last three to four years and they are known to us."
He said their sudden presence at the Hamilton Lake may be due to them discovering the line of eucalyptus trees at the north end of Innes Common.
Council monitors rooks and controls them by nest poisoning.
"Rooks don't spread very far so we know the areas they hang out and find where they are nesting and undertake a control of them in spring," Quinn said.
Rooks are pests because they feed on newly sown crops and damage pasture by tearing it up in search of seeds and grubs. In large numbers, they can devastate emerging crops, forcing farmers to re-sow seed.
Rooks are members of the same family as crows and ravens. The Waikato Regional Council website said many people confuse rooks with crows, but there are no crows in New Zealand.
People should not try to control rooks themselves, as they are likely to spread further.
Landowners may not carry out rook control on their properties and it is illegal to keep a rook as a pet.
- Waikato Times