Bluebirds have been seen in and near the city during the coldest periods of seven of the last thirteen winters.  The first spring migrants arrive usually in the second week of February, and by the 20th or 25th are common.  The bulk of the migrants pass through during the first two weeks of March.  Flocks of southbound migrants have been noted as early as September 18th, but the largest flocks are seen about a month later.