LESTER HOLT: Tonight on DATELINE… he was hot on the trail of a wonton traffic offender – until a mama duck and her babies crossed the line into temptation. And/or the middle of the road. Here’s Dateline’s Josh Mankiewicz.

JOSH MANKIEWICZ: You saw the driver, and he was…

TRAFFIC OFFICER MARK JAMES: We clocked the vehicle at 52 miles per hour.

MANKIEWICZ: But the speed limit on that stretch of road is, what, 30? 35?

JAMES: The driver was well above the speed limit.

MANKIEWICZ: And your first thought was?

JAMES: Let’s take care of this so we can keep the people of Portland safe.

MANKIEWICZ: But there was a problem.

JAMES: Yes there was.

MANKIEWICZ: A big problem.

JAMES: It was a little problem, actually.

LESTER HOLT, FROM THE DATELINE NBC STUDIOS: Coming up, this Portland police pursuit is about to take flight – or IS it? When The Case Of The Highway Duck continues…

A mama duck and baby ducks interrupt a police chase.

HOLT: Mark James was on a high-speed pursuit down the streets of Portland. One wrong move could spell the end for this decorated traffic officer – or the car he’s sworn to stop. But no one could have expected this fast and furious street chase to come to a crashing halt. Again, here’s Josh Mankiewicz.

MANKIEWICZ: You were chasing the speeder… .

JAMES: I was in pursuit of the vehicle, heading northbound with my lights on, and there she was.

MANKIEWICZ: The duck.

JAMES: The duck, yes.

MANKIEWICZ: And she was not speeding.

JAMES: No, she was not. She had some babies with her and they were in no rush.

MANKIEWICZ: It must have been jarring to go from high speed to a snail’s pace in a blink of an eye.

JAMES: We’re trained for these sorts of situations.

MANKIEWICZ: You have to be ready for anything. Speeders, ducks… speeders followed by ducks…

JAMES: Right.

MANKIEWICZ: Speeders followed by ducks… followed by the giant insects from Starship Troopers, possibly.

JAMES: Well…

MANKIEWICZ: I mean, you just never know.

JAMES: That’s true, you never know.

MANKIEWICZ: Did you at all suspect that the ducks might be accomplices?

JAMES: To the speeder?

MANKIEWICZ: To the speeder.

JAMES: That’s one we haven’t seen yet.

MANKIEWICZ: What about the giant insects from Starship Troopers?

JAMES: What about them?

MANKIEWICZ: Have you ruled them out as suspects?

JAMES: The driver is the suspect in this case.

MANKIEWICZ: The primary suspect?

JAMES: The primary suspect.

MANKIEWICZ: But not the only suspect.

JAMES: Um…

MANKIEWICZ: Could the ducks have been hired by the God Bug in Starship Troopers to head off your high-speed pursuit so that the driver could get away?

JAMES: That’s a lot of speculation…

HOLT: But could there be more to a simple case of speeding on this quiet Portland street? We’ll find out tomorrow night, when Josh Mankiewicz presents The Case Of The Highway Duck, Part 2: Behemecoatyl Rising, here on Dateline.