Afternoon sun silhouettes palm fronds as storm clouds gather over Arenal volcano; La Fortuna, Costa Rica.

Silty waters of Rio Sucio emerge from volcanic highlands to join with clearer stream near Santa Clara, Costa Rica.

Male green iguana (Iguana iguana) is one of many that roam free outside gift shop near La Fortuna, Costa Rica.

Male green iguana (Iguana iguana) poses by garden wall near La Fortuna, Costa Rica.

Red-eyed tree frog (Agalychnis callidryas) perches on man's thumb; Las Horquetas, Costa Rica.

Red-eyed tree frog (Agalychnis callidryas), aka red-eyed leaf frog or gaudy leaf frog, perches on man's hand; Las Horquetas, Costa Rica.

Blue jeans dart frog (Dendrobates pumilio), sits on leaf while inflating throat; Las Horquetas, Costa Rica.

Soley Hyman, age 9, stands still and stifles big laugh as red-eyed tree frog rests on her neck and Caitlin Seibel, age 9, watches with delight; Las Horquetas, Costa Rica.

Soley Hyman, Caitlin Seibel (both age 9) and sister Kelsey Seibel, 11, marvel up close over red-eyed tree frog perched on guide's finger; Las Horquetas, Costa Rica.

Owl butterfly (Caligo eurilochus sulanus) displays its wing's defensive eye pattern; La Fortuna, Costa Rica.

Doris longwing (Heliconius doris) butterfly rests on flower after feeding; La Fortuna, Costa Rica.

Two malachite (Siproeta stelenes) butterflies mate on underside of leaf; La Fortuna, Costa Rica.

Kelsey Seibel, age 11, holds millipede as sister Caitlin, 9, watches; Santa Elena National Park, Costa Rica.

Millipede crawls across woman's hand; Santa Elena National Park, Costa Rica.

Rufous-tailed hummingbird (Amazilia tzacatl) sits in nest; Santa Clara, Costa Rica.

Blond variation of white-nosed coati (Nasua narica) rests in tree branches; Playa Blanca, Costa Rica.

Chestnut-mandibled toucan (Ramphastos ambiguus ambiguus); Las Horquetas, Costa Rica.

Head portrait of chestnut-mandibled toucan (Ramphastos ambiguus ambiguus); Las Horquetas, Costa Rica.

Pair of white-faced capuchins (Cebus capucinus), aka white-throated capuchins and white-faced monkeys, sit in tree; Playa Blanca, Costa Rica.

Ecoteach guide Alex Rojas helps Kelsey Seibel (11), Soley Hyman (9) and Caitlin Seibel (9) watch and count scarlet macaws returning to nests in evening at Nativa Resort; Tarcoles, Costa Rica.

Ecoteach guide Alex Rojas helps Kelsey Seibel (11), Soley Hyman (9) and Caitlin Seibel (9) watch and count scarlet macaws returning to nests in evening at Nativa Resort; Tarcoles, Costa Rica.

Scarlet macaw (Ara macao) displays brilliant feather colors in flight near Carara National Park, Costa Rica.

Nesting pair of scarlet macaws (Ara macao) perch in tree near Carara National Park, Costa Rica.

Scarlet macaw (Ara macao) lands on nesting hole in tree near Carara National Park, Costa Rica.

Scarlet macaw parents (Ara macao) perch in nesting hole in tree bordering Carara National Park, Costa Rica.

Scarlet macaw chick (Ara macao) peers from nesting hole in tree bordering Carara National Park, Costa Rica.

Ecoteach guide Alex Alvares Rojas briefs participants on sea turtle conservation at Estacion Las Tortugas preserve on Caribbean; Rio Pacuare, Costa Rica.

Ecoteach guide Alex Alvares Rojas briefs participants on leatherback nests and sea turtle conservation at Estacion Las Tortugas preserve on Caribbean; Rio Pacuare, Costa Rica.

Ecoteach girls play board game and learn about sea turtle conservation at Estacion Las Tortugas visitors center; Caribbean coast near Rio Pacuare, Costa Rica.

Ecoteach participant Soley Hyman (age 9) measures turbidity in river canal for GLOBE data collection; Estacion Las Tortugas reserve on Caribbean, Rio Pacuare, Costa Rica.

Director Stanley Rodriguez helps Ecoteach kid Soley Hyman use microscope to search sand grains for mites that destroy turtle eggs; Estacion Las Tortugas reserve; Rio Pacuare, Costa Rica.

Ecoteach girls search for leatherback sea turtles laying eggs on beach at Estacion Las Tortugas sea turtle conservation station on Caribbean; Rio Pacuare, Costa Rica.

Leatherback sea turtle (Dermochelys coriacea) covers nest after laying eggs on beach at Estacion Las Tortugas sea turtle station on Caribbean coast; Rio Pacuare, Costa Rica.

Ecoteach team catches eggs as leatherback sea turtle, Dermochelys coriacea, lays at Estacion Las Tortugas reserve; Rio Pacuare, Costa Rica.

Red headlamps illuminate bag of leatherback sea turtle eggs collected from laying female at Estacion Las Tortugas reserve near Rio Pacuare, Costa Rica.

Ecoteach team measures leatherback sea turtle that has just laid eggs at Estacion Las Tortugas reserve; Caribbean, Rio Pacuare, Costa Rica.

Ecoteach team measures leatherback sea turtle that has just laid eggs at Estacion Las Tortugas reserve; Caribbean, Rio Pacuare, Costa Rica.

Ecoteach team measures leatherback sea turtle that has just laid eggs at Estacion Las Tortugas reserve; Caribbean, Rio Pacuare, Costa Rica.

Ecoteachers Soley Hyman and Alvaro Rodriguez carry fresh eggs from leatherback sea turtle to bury in Estacion Las Tortugas hatchery; Rio Pacuare, Costa Rica

Ecoteachers Soley Hyman and Alvaro Rodriguez carry fresh eggs from leatherback sea turtle to bury in Estacion Las Tortugas hatchery; Rio Pacuare, Costa Rica

Ecoteach kid Soley Hyman (age 9) transfers eggs collected from leatherback sea turtle to hole in sand at hatchery; Estacion Las Tortugas reserve, Rio Pacuare, Costa Rica.

Ecoteacher Soley Hyman (9) and Alvaro Rodriguez measure depth of artificial nest in sea turtle hatchery at Estacion Las Tortugas reserve; Caribbean, Rio Pacuare, Costa Rica.

Ecoteach families travel by boat on canal to Estacion Las Tortugas conservation station help save leatherback sea turtles; Caribbean near Rio Pacuare, Costa Rica.

Ecoteach families boat from Estacion Las Tortugas conservation station after helping save leatherback sea turtles along Caribbean coast near Rio Pacuare, Costa Rica

Ecoteach families boat from Estacion Las Tortugas conservation station after helping save leatherback sea turtles along Caribbean coast near Rio Pacuare, Costa Rica

Ecoteach participant Caitlin Seibel (age 9) digs in sand on Caribbean beach at Estacion Las Tortugas sea turtle conservation station near Rio Pacuare, Costa Rica.

Local boy sits on dormitory porch as Ecoteach girl Kelsey Seibel (age 11) and family prepare to leave Estacion Las Tortugas sea turtle reserve; Caribbean, Rio Pacuare, Costa Rica

Young girl poses for portrait at Estacion Las Tortugas sea turtle conservation station on Caribbean coast near Rio Pacuare, Costa Rica.

Stamens reach upward from center of bright purple blossom; La Fortuna, Costa Rica.

Orchid flower; Arenal National Park, Costa Rica.

Distant waterfall cascades amid lush mountains and rainforest of the Catarata del Rio Fortuna Biological Reserve in Costa Rica.

Ecoteach girls Kelsey Seibel (left, age 11) and Soley Hyman (age 9) swim in icy river downstream from waterfall on the Catarata del Rio Fortuna Biological Reserve, Costa Rica.

Ecoteach girls Kelsey Seibel (left, age 11) and Soley Hyman (age 9) admire rainforest during Ecoteach hike in Arenal National Park, Costa Rica.

Don Juan Bautista Castro has Ecoteach participants toss corn from field at his organic farm near La Fortuna, Costa Rica.

Juan Bautista Castro shows Ecoteach participant Soley Hyman (age 9) how to sheath machete at his organic farm near La Fortuna, Costa Rica.

Ecoteach participant Caitlin Seibel (age 9) chops down cassava tree with machete at Don Juan Bautista Castro's organic farm near La Fortuna, Costa Rica.

Ecoteach participant Luke Young (age 16) pulls cassava roots from ground at Don Juan Bautista Castro's organic farm near La Fortuna, Costa Rica.

Ecoteach participant Kelsey Seibel (age 11) milks cow at organic farm of Don Juan Bautista Castro; La Fortuna, Costa Rica.

Ecoteach participant Kelsey Seibel (age 11) milks cow at organic farm of Don Juan Bautista Castro; La Fortuna, Costa Rica.

Calf peers through high grass at camera; La Fortuna, Costa Rica.

Ecoteach girls Soley Hyman (9), Kelsey Seibel (11) and Caitlin Seibel (9) eat mangos while guide Alex Alvarez Rojas prepares the fruit for blender at organic farm of Juan Bautista Castro; La Fortuna, Costa Rica.

Ecoteach guide Alex Alvarez Rojas leads a nature hike in the cloud forest of Santa Elena National Park, Costa Rica.

Ecoteach guide Alex Alvarez Rojas leads a nature hike in the cloud forest of Santa Elena National Park, Costa Rica.

Cloud Forest School sixth graders Douglas Rodriguez Cruz and Jocelyn Mena Mora examine flower in rainforest of Santa Elena National Park, Costa Rica.

Ecoteach guide Alex Alvarez Rojas points out birds in rainforest as Luke Young (16, back) and Cloud Forest School student Douglas Rodriguez Cruz (12, front) join in at Santa Elena National Park, Costa Rica.

Cloud Forest School sixth-grader Jocelyn Mena Mora admires rainforest of Santa Elena National Park, Costa Rica.

Ecoteach kids examine insects during night hike in cloud forest of Monteverde, Costa Rica.

Ecoteach participants admire glowing firefly during night hike in cloud forest of Monteverde, Costa Rica.

Jazmin Brenes Araya (12) stands beside National Wildlife Federation Schoolyard Habitat sign with handful of garbage and a juicy worm dug from composte bin at Cloud Forest School; Monteverde, Costa Rica.

Silvia Elena Santamaria Badilla (11) stands beside National Wildlife Federation Schoolyard Habitat sign with handful of garbage and a juicy worm dug from composte bin at Cloud Forest School; Monteverde, Costa Rica.

Environmental programs teacher Karen Gordon gives students instructions on seedling transplantation at the Cloud Forest School; Monteverde, Costa Rica.

Hellen Rebeca Solis Mora (12) and Carolina Soto Villalobos (age 11) cradle reforestation seedlings in greenhouse at Cloud Forest School; Monteverde, Costa Rica.

Environmental programs teacher Karen Gordon shows Jazmin Brenes Araya (12) how to care for reforestation seedling at Cloud Forest School; Monteverde, Costa Rica.

Kids transplant seedlings from greenhouse in outdoor nursery at Cloud Forest School; Monteverde, Costa Rica.

Sixth-grader Luis Dario Villalobos Castro (12) holds reforestation seedlings at Cloud Forest School; Monteverde, Costa Rica.

Three first graders eat leafy vegetable from their schoolyard garden at Cloud Forest School; Monteverde, Costa Rica.

Cloud Forest School students march through old cattle pasture clearing after planting seedlings for reforestation project; Monteverde, Costa Rica.

Cloud Forest School students march through old cattle pasture clearing after planting seedlings for reforestation project; Monteverde, Costa Rica.

Fifth-grade student Carolina Soto Villalobos (age 11) poses with shovel in old cattle pasture after planting seedlings for reforestation project at the Cloud Forest School; Monteverde, Costa Rica.

Fifth-grade student Carolina Soto Villalobos (age 11) plants seedling for reforestation project at the Cloud Forest School while fourth-grader Jonathan Siles Godar (age 10) helps; Monteverde, Costa Rica.

Palm trees frame white sands and azure waters of Playa Blanca on the Pacific coast at Punta Leona, Costa Rica.

Palm trees frame white sands and azure waters of Playa Blanca on the Pacific coast at Punta Leona, Costa Rica.

Ecoteach girl Soley Hyman (age 9) ziplines upside down through Pacific coastal rainforest on the Monkey Trail Canopy Tour at Hotel Punta Leona, Costa Rica.

Ecoteach girl Kelsey Seibel (age 11) ziplines upside down through Pacific coastal rainforest on the Monkey Trail Canopy Tour at Hotel Punta Leona, Costa Rica.

Ecoteach girl Caitlin Seibel (age 9) ziplines upside down through Pacific coastal rainforest on the Monkey Trail Canopy Tour at Hotel Punta Leona, Costa Rica.

Ecoteach girl Caitlin Seibel (age 9) ziplines through Pacific coastal rainforest on the Monkey Trail Canopy Tour at Hotel Punta Leona, Costa Rica.

Ecoteach girl Soley Hyman (age 9) ziplines through Pacific coastal rainforest on the Monkey Trail Canopy Tour at Hotel Punta Leona, Costa Rica.

Ecoteach family paddles down Sarapiqui River on whitewater raft trip; Las Horquetas, Costa Rica.