Norwegian authorities said they did not know who had dropped dough on the E6 highway near Gardermoen on Wednesday, but said they believed the birds had been pecking away at the unusual bounty since early morning.
The police received reports of several birds crushed by cars at around 1pm, reported news network NRK:
"The most exciting question is who is missing their dough," said Roads Agency (Vegvesenet) spokeswoman Trude Lindstad.
"No one's dared to admit it to us yet."
The agency asked private contractors Peab to clean up along the highway.
"At first I thought it was doughnut dough," said Peab employee Kjell Olsen. "But now I think it must have been frozen bread dough. I have picked up the biggest lumps, but there was just so much of it - several miles with dough spillage. I had to leave the smaller pieces."