This week's calendar is heavy on lectures and classes -- you could attend one a day if you wanted to:
Tonight is the monthly program at Brown Planetarium in Arlington ($2/3).
Tuesday at noon there's a tour of medicinal and poisonous plants at the US Botanical Garden on the Mall (free).
And then you can get up early on Thursday morning and help count birds at Jug Bay. They're looking for waterbirds and raptors, and often see bald eagles on their counts.
Friday night is the monthly show at the Owens Planetarium in Lanham. They'll have a talk by someone from the University of Maryland about imaging the very early universe with the Combined Array for Research in Millimeter-wave Astronomy (CARMA), and then "explore some visible-wavelength wonders of the planetarium sky" ($2/$4).
Saturday, Casey Trees is having a class on Trees 101. " This course provides a foundation in tree anatomy, tree identification and an overview of how trees function to provide the benefits we enjoy in the urban forest. The session will culminate with a street tree identification walk led by Casey Trees staff." (free; pre-registration required)
And on Sunday, the Audubon Naturalist Society will have a class on winter ecology in Chevy Chase. They promise to explore the many strategies organisms "from grasses to grackles to gray tree frogs" use to survive winter. (free; pre-registration required)
Enjoy! As always, there's more on our full calendar.