CORNWALL-ON-HUDSON-The Museum of the Hudson Highlands will host a talk by Dr. John Waldman about the history, sea life and environment of the Hudson estuary south of the Highlands. The event will be held at 7:30 p.m. on Thursday, Oct. 6, at Painter's Tavern on Hudson St. in Cornwall-on-Hudson. Waldman, a professor of biology at Queens College, will base his talk on his book, "Heartbeats in the Muck," which received a New York City Book Award for Natural History in 2000. He will chronicle how the estuary once bristled with oysters and striped bass, and how it has suffered centuries of environmental abuse. His focus will be on the animals, water quality, and habitats, with personal accounts of his explorations on the river. Admission is $7 for nonmembers, and $4 for members. Reservations are not required. For more information, call 534-5506 ext. 204, or visit www.museumhudsonhighlands.org.