ANN ARBOR, MI - As communities across the nation wrestle with the arrival of rentable electric scooters, Ann Arbor has started confiscating Bird scooters left on city streets and sidewalks.

The electric scooter-share company known as Bird dropped dozens of its rentable scooters in Ann Arbor on Sept. 7, prompting the city to quickly warn users they could be ticketed for riding them on sidewalks or leaving them parked on streets.

Now the city is raising concerns about Bird scooters left parked on public sidewalks, which is where most of them are being parked, saying it can impede pedestrian traffic.

A city worker who asked to remain anonymous shared a photo of Bird scooters locked up in a city public works garage last week, saying the city's community standards officers were confiscating them.

City spokeswoman Lisa Wondrash confirmed the city has impounded more than two dozen Bird scooters that the city determined were improperly left in bicycle lanes, streets or on sidewalks and may have impeded pedestrian, bicycle or vehicular traffic.

"The company has been notified that their equipment has been collected by the city and is being securely stored at our Public Works Facility," Wondrash said in an email. "The city welcomes alternative modes of transportation for residents and visitors, and city staff are actively working with Bird on a licensing agreement."

Additional details about the potential licensing agreement weren't immediately available.

Bird couldn't be reached for comment.

Wondrash said the city is not trying to rid Ann Arbor of all rental scooters, but they can't be left in the public right-of-way.

Wondrash shared this message from the city: "Do not leave scooters parked on the roads, sidewalks or bike paths and make sure they are clear from driveways, access ramps and fire hydrants."

The city offers this additional advice to Bird users: "Always wear a helmet and, when you are finished riding, it's important to keep scooters from interfering from the public right of way when stored."

Since Bird's current model seems to rely on leaving them along public sidewalks for users to grab and go, those restrictions could be problematic for the company.

Wondrash said it's a matter of safety and the scooters should be left in a safe location so they're not impeding pedestrians or others.

Wondrash said the city is not concerned about Bird scooters if they're left on private property and the city is not confiscating scooters because of concerns about riders falling off and getting injured, which has been a concern cited in other communities.

The Washington Post recently reported that the rollout of electric scooters in some communities has resulted in serious injuries and trips to the emergency room.

There still are dozens of not-yet-confiscated Bird scooters available to rent in Ann Arbor, and many are parked along city sidewalks in the downtown area and around the University of Michigan campus.

Hoping to grow its business and get more people to make environmentally friendly commutes, Bird is making a pop-up tour across the United States, bringing its scooters to many cities and college campuses. In addition to Ann Arbor and Detroit, Bird also has hit East Lansing, according to the company's website.

The scooters cost $1 to activate and 20 cents per minute to ride. They can travel up to 15 mph.

To use them, users must download the Bird mobile app, which shows the locations of scooters on a map.

Bird encourages users to ride safely, wear a helmet and not ride on sidewalks.

Per city ordinance, it's unlawful to operate a Bird scooter or any other motorized vehicle on sidewalks.

Per state law, motorized scooters cannot operate in bicycle lanes, but they can operate on the road as close to the right curb as possible.

Though many users have been riding Bird scooters on sidewalks, which the city has warned against, Ann Arbor Police Department Lt. Renee Bush said she's not aware of anyone being ticketed by AAPD for doing so.

City Council Member Kirk Westphal, an alternative transportation advocate, said he hasn't seen data to show whether the scooters are replacing car trips, but to the extent that they provide a cleaner and more affordable means of getting around, he's guessing the community will favor working out a relationship with Bird.

He said Bird caught the city by surprise when it rolled out its service in Ann Arbor.

"The surprise approach in introducing a new technology typically doesn't sit well with a government structure," he said. "I recall the collective freakout when Uber and Lyft came onto the scene, so I hope this process of acclimation and legislation takes a long view."

From a pedestrian and disability advocate's standpoint, he said, it would be unacceptable if they present an imminent danger to people.

Ann Arbor News intern McKenzie Sanderson contributed to this story.