They're there!

Eastern Phoebe
Photo by Lloyd Spitalnik - April 10, 2008
http://www.lloydspitalnikphotos.com

From e-birds, the New York City birdwatching listserv:

It's spring again in CP. 2-3 Phoebes seen near Turtle Pond at around 11:30 AM, Sunday morning. Another reported earlier in Shakespeare Garden.

Alan Margolies (with others on a Sunday morning walk)