On my way home Monday night with my window down while crossing the Merrimack River heading south, a familiar bird call was heard.  It was the whining call of a peregrine.  A juvenile Peregrine was discovered on the south side of a roof overlooking the Merrimack River.  The peregrine was facing the sun and hopping around in an area on the roof with grass.  It seemed to be whining for food.  It moved to the edge of the roof, and thankfully, provided a clear look at the black and green leg bands attached by staff at Mass Wildlife.  This juvenile fledged on June 12 from the Lawrence nest box in the nearby Ayer Mill Clock Tower.  According to the book on peregrine fledglings by Steve Sherrod, most peregrine juveniles disperse on their own once they are proficient at killing prey.  Some individuals disperse before others, and a few are reluctant to disperse unless food is completely withheld by parents.