Hugh Whitney, the Newfoundland and Labrador government's chief veterinarian, believes more than 40 seagulls found dead near Quidi Vidi Lake were poisoned when they ate coffee grounds. (CBC)

Several dozen seagulls found dead recently in the east end of St. John's were killed by an overdose of caffeine, an expert says.

More than 40 seagulls were found dead in the area of Quidi Vidi Lake in February.

Hugh Whitney, the Newfoundland and Labrador government's chief veterinarian, said after an infectious disease was ruled out, investigators looked for other reasons to explain the sudden deaths.

"Our next choice after an examination like that is to look for something toxic," Whitney told CBC News Monday.

"[The] surprise to us, what came up, is that the gulls had caffeine in their stomachs."

How the caffeine came to kill so many birds at once is not precisely known, although Whitney believes the seagulls ate through garbage bags and found coffee grinds.

"We know they're scavengers [so] we're probably looking at grinds…. No doubt there's plenty of garbage in town that has coffee grinds in it," Whitney said.

'Relatively local'

Although Quidi Vidi Lake is a short drive — or flight — from the regional garbage dump at Robin Hood Bay, Whitney thinks the birds likely were poisoned near where their bodies were found. With previous poisonings at the dump, he said, seagull carcasses were found throughout the city.

"I think that this was something that was relatively local to Quidi Vidi Lake, because that's where all the reports were," Whitney said.

The issue is the second recent series of bird deaths in eastern Newfoundland.

Since last week, more than 200 seabirds have been found on shores stretching from Bonavista on Newfoundland's northeast coast to Fermeuse and Cape Broyle, on the Southern Shore, south of St. John's.

Whitney said he expects to receive more reports of deaths of murres, which he believes are linked to pack ice that has accumulated along the coastlines.

"Our assessment is starvation. It's not 100 per cent clear why they starved. We could look at all the ice out there but presumably either there isn't enough to eat or they can't get access to it," he said.

"It's kind of hard to know exactly why. We just look at the birds and see that they're starved."