Watch as hundreds of bats swirl out of Bracken Cave in Texas.

The Monarch Larva Monitoring Project (MLMP) is a citizen science project involving volunteers from across the United States and Canada in monarch research. It was developed by researchers at the University of Minnesota to collect long-term data on larval monarch populations and milkweed habitat. The project focuses on monarch distribution and abundance during the breeding season in North America.

Celebrate Urban Birds is a citizen science project focused on better understanding the value of green spaces for birds. This project connects people of all ages and backgrounds to birds and the natural world through the arts and fun neighborhood activities.

El Monarch Larva Monitoring Project (MLMP) es un proyecto de ciencia ciudadana en el que participan voluntarios de todo Estados Unidos y Canadá en la investigación de monarcas. El proyecto se centra en la distribución y abundancia de las monarcas durante la temporada de reproducción en América del Norte.

Celebrate Urban Birds es un proyecto bilingüe de ciencia participativa en The Cornell Lab of Ornithology.

Breeding and the greening of the landscape are tied to another major spectacle of spring: the mass movements of animals as they take advantage of spring’s bounty. Meet the scientists who track the journeys of animals such as butterflies, birds, bison and bats over vast distances, from winter refuge to spring nesting grounds.

Meet Citizen Scientist David Cohen and see how Cornell Lab of Ornithology's Bird Cams Lab has provided him a window into studying the behavior of birds.

A crucial component of biological research is monitoring the populations of wildlife in our protected parks and reserves. In this clip, bear biologist Dr. Rae Wynn-Grant and Maryland DEC bear biologist Harry Spiker are meeting the newest bear cubs in Savage River State Forest, Maryland.

The goal of Bird Cams Lab is to join viewers from around the world to make new discoveries using live streaming and archived camera footage focused on wild bird nests and feeders.

¡Con cámaras de transmisión en vivo, The Cornell Lab of Ornithology ha proporcionado una vista de pájaro a más de un millón de personas al año!

In this stunning opening sequence, watch a lamb being born into the world on Nanne Kennedy's wool farm.

Spring is a time of birth and rebirth for plants and animals across the country. Join us for night one of a three-night adventure about the season that sets the natural world in motion.

Track a Lilac invites you to find a nearby lilac and report whether they see leaves or flowers on their plant. The data contributes to a national database that will be used by researchers to better understand the timing of lilac leafing and blooming across the country.

Get spring savvy with these fun facts about the season! From the tilt of the earth to unique animal behaviors, there are several interesting ways you can tell it's springtime!

We visited wool farmer Nanne Kennedy in Washington, Maine to get a sneak peek at her pregnant sheep. We'll be returning to her farm on April 29 for the premiere of American Spring LIVE in hopes to see one of the new lambs actually being born.

Executive Producers, Fred Kaufman and Al Berman, along with host Juju Chang and science correspondent Thor Hanson share a bit of insight into the upcoming NATURE three-night live broadcast event, American Spring LIVE.

SciStarter is the place to find, join, and contribute to science. With more than 3,000 projects and events searchable by topic, location, age-level and more, you’re sure to find the right match, anytime, anywhere.

From Sequoia to the Everglades, from bear cubs to hummingbirds, from hibernation to pollination, Spring is coming to you, Live on PBS.

How much do you know about the Giant Sequoias? Since our American Spring LIVE team will be based near the legendary groves, we figured it was the perfect time to brush up our knowledge of the Sequoias with a few fun facts about the world's oldest trees.

The change from winter to spring is a slow and subtle process, but the transformation is nothing short of amazing. Witness the change in 60 seconds to see just how magical it can be.