Old tennis balls are being used in an unusual way to help us learn more about one of the rarest mammals  in the country. Harvest mice are only about 2 inches ( 5 cm) long. This spring and summer, wildlife experts are encouraging people to report sightings of harvest mice so that records can be built up about numbers and locations. Meadows and grassland are animals' traditional homes but as farming methods change over time, the habitats are being lost and numbers are thought to be _ . Old tennis balls, complete with penny-sized holes, make a strong and popular choice of home for the mice and around 200 are available for surveyors to distribute and monitor, after being donated by a local tennis club. The project, supported by the Leicestershire County Council, is thought to be the biggest of its kind ever run in Leicestershire. County Council wildlife expert, Helen O'Brien; said, " Little is known about the creature's present situation locally so we need people to look in tall grass and fields and send in their information. The information will help us track numbers and tell us where we need to focus our attention to safeguard their future. " Anyone interested in getting involved  , can pick up tips and learn more about harvest mice on a training day. This is taking place between 7:30 pm and 9:30 pm on Monday, 14th June at the County Council's Environmental Resource Centre in Birstall. People living in Leicester, Leicestershire and Rutland can get involved with the survey or book a place on the training day by calling Gareth Price at 0116-267-1950. What is the best title for the passage?
Harvest mice like old tennis balls The importance of tennis balls The rarest animal :harvest mice Harvest mice's homes are being lost