AT HOME, MY PHOTOS confirm that the big beaver is definitely José, and a hasty Google search for "young beaver" (bad word choice) reveals that the other rodent is not an adolescent beaver but an adult muskrat. I start to wonder if José and the muskrat aren't, well . . . nah, they probably just share the same bathwater. My probing turns up no examples of beavers getting intimate with their rodent cousins, so I devise my own plan: Borrow night-vision binoculars. Stake out the lodge.

At 4:30 p.m. on Wednesday, June 4, Critter Watch '08 begins. It's cooler but, again, no José.

A red–winged blackbird swoops to perch on a droopy branch. A woodpecker sounds exhausted by his own jackhammering. The sky fades from denim to peach to charcoal. For four hours, exceptionally unhurried and underwhelmed, I can't help but feel that everything is downright portentous—even the quilt of fireflies over the river, which seems to offer commentary on the aim of life itself. Do not conserve your energy, the lightning bugs say; set your very being ablaze!

Still no José. I cross the street to McDonald's and order a Southwest Salad with Chicken. There I strike up a conversation with a neighboring table of mothers and daughters eating sundaes. They're friendly, but a little taken aback. It's not every night you run into an extremely outgoing white guy in the Bronx asking questions about urban fauna. They say the only wildlife they know of are "cucarachas."

"What, you like Crocodile Dundee?" a high–school boy at a nearby booth wants to know.

I explain that I'm a journalist planning to spend the night observing the historic beaver.

"Jeff Irwin?" a second boy asks.

"Oh, snap!" a girl says.

Back at the river, the reflection of an airplane lurches forward on little waves—a creature is stirring—and I turn on the Yukon Advanced Optics Digital Night Vision Ranger 5x42 binoculars. The oily scene transforms into a grainy black-and-white photo, and there, near a raft of brush caught midstream after last night's windstorm, I glass José. Devil José. Seen through the binoculars, his fur has the coarse lines of a woodblock print and his eyes glow bright white. He U–boats toward me until all I can see is his two burning orbs. I rise to tiptoe for shore and he slaps his tail down with a deafening crack—kaploosh! I fall to the tree, hugging it with arms and legs.

Sometime after 1 a.m., I unroll my Calvin Klein bedsheet in the ornamental–conifers section of the garden, amid the wailing of sirens. Muskrat love? What was I thinking?