Bird nests range from a scrape on the ground to intricately woven hanging baskets. Join volunteer naturalists for an easy end of winter walk in search of some of these diverse structures created by amazing avian architects. All Ages Welcome Registration for most programs begins on the 20th of the month before the event. Registration required. Register Registration is required through Discover Boulder County, Parks & Open Space’s volunteer and event registration system. If you’re new to the system, you'll need to create an account. But it’s easy and we only use your contact information to communicate about events you register for. We will never sell or give your information to a third party.