This post has been updated.

Flying out of Baltimore-Washington International Marshall Airport this winter? You might be joined by some tiny, furry company. Mice were spotted on two different days at BWI Airport, prompting an investigation by health officials.

The Anne Arundel County Department of Health received two reports of mice in different concourses. The first complaint, received on Dec. 4, involved Concourse D; the second complaint was received Monday and concerned Concourse A. 

Both complaints stemmed from travelers seeing “mice running around,” said Elin Jones, spokeswoman for the department. 

The mice situation, which was first reported by the Baltimore Sun, is an issue that crops up during the winter, said BWI spokesman Jonathan Dean. 

During the coldest months, mice seeking warmth find their way into the airport. The BWI terminal is about 2 million square feet and it is surrounded by about 3,600 acres of largely open land, Dean said. 

“BWI Marshall has a comprehensive pest control program in place,” Dean said. “We have a full-time pest control service located here on site at the airport.” 

The airport also works to make sure that the restaurants, shops and other stores do their best to minimize potential rodent attractions. “We are also working in close conjunction with our airport tenants to emphasize the importance of good pest control practices,” he said.  

There don’t appear to be more mice at the airport than during previous years, he said. But the issue might be exacerbated by the airport’s $100 million construction project, which began in June and will finish next summer. The project includes a connector linking the airport’s A, B and C concourses as well as expanded space for shops and restaurants. 

The project “has created additional locations for pests to access the building,” Dean said. 

The Anne Arundel County Department of Health investigation is focused on restaurants and other spots serving food in the concourses where mice were seen. Investigations can take up to a month to complete, Jones said.