We were in Central Park about a month ago, on March 11. We got to the Ramble at around 8:30 A.M. and quickly saw two unleashed dogs. About 9:30 we saw this one, west of the Great Lawn.
This morning we got to the Ramble around 7:30 and immediately saw 3 unleashed dogs, 2 in the open area just north of the Boathouse and one in what birders call "Maintenance Meadow". Here is one: