Ostional Wildlife Refuge

🇨🇷 Costa Rica

🐢 Pacific Ridley Arribada at Ostional

🧭 Guide required ⏱ 1 day 🥾 Easy trails

🌍 #153 Global · 3.7 ★★★★★ ★★★★★ #28 in Central America #75 in Tropical Forest

Nicoya Peninsula, Costa Rica 727 spp. recorded

Ostional Wildlife Refuge protects one of the two most important olive ridley turtle nesting beaches on Earth. During peak season (September–November), up to 500,000 turtles emerge from the Pacific in a single arribada — an ancient synchronized mass-nesting event that occurs in only a handful of places worldwide.

9.958° N 85.653° W

Wildlife

⭐ Iconic Species

Pacific Ridley

Lepidochelys olivacea

30–40% · Possible

Mantled Howler Monkey

Alouatta palliata

80–90% · Very likely

Black Spiny-tailed Iguana

Ctenosaura similis

80–90% · Very likely

White-nosed Coati

Nasua narica

50–60% · Likely

📊 Most Spotted

Black Vulture

Coragyps atratus

70–80% · Very likely

Great Kiskadee

Pitangus sulphuratus

70–80% · Very likely

Rufous-backed Wren

Campylorhynchus capistratus

60–70% · Likely

Green Iguana

Iguana iguana

60–70% · Likely

Great-tailed Grackle

Quiscalus mexicanus

60–70% · Likely

Variegated Squirrel

Sciurus variegatoides

60–70% · Likely

Hoffmann's Woodpecker

Melanerpes hoffmannii

50–60% · Likely

Black-headed Trogon

Trogon melanocephalus

50–60% · Likely

Tropical Kingbird

Tyrannus melancholicus

50–60% · Likely

Turkey Vulture

Cathartes aura

40–50% · Likely

Brown Pelican

Pelecanus occidentalis

40–50% · Likely

Spotted Sandpiper

Actitis macularius

40–50% · Likely

⭐ Iconic Species

Mantled Howler Monkey

Alouatta palliata

80–90% · Very likely

White-nosed Coati

Nasua narica

50–60% · Likely

📊 Most Spotted

Variegated Squirrel

Sciurus variegatoides

60–70% · Likely

Central American White-faced Capuchin

Cebus imitator

10–20% · Possible

Common Raccoon

Procyon lotor

10–20% · With luck

Northern Tamandua

Tamandua mexicana

10–20% · With luck

Mexican Hairy Dwarf Porcupine

Sphiggurus mexicanus

Insufficient data

Common tent-making Bat

Uroderma bilobatum

Insufficient data

Gray Fox

Urocyon cinereoargenteus

Insufficient data

White-tailed Deer

Odocoileus virginianus

Insufficient data

Humpback Whale

Megaptera novaeangliae

Insufficient data

Northern Ghost Bat

Diclidurus albus

Insufficient data

Killer Whale

Orcinus orca

Insufficient data

Greater Sac-winged Bat

Saccopteryx bilineata

Insufficient data

📊 Most Spotted

Black Vulture

Coragyps atratus

70–80% · Very likely

Great Kiskadee

Pitangus sulphuratus

70–80% · Very likely

Rufous-backed Wren

Campylorhynchus capistratus

60–70% · Likely

Great-tailed Grackle

Quiscalus mexicanus

60–70% · Likely

Hoffmann's Woodpecker

Melanerpes hoffmannii

50–60% · Likely

Black-headed Trogon

Trogon melanocephalus

50–60% · Likely

Tropical Kingbird

Tyrannus melancholicus

50–60% · Likely

Turkey Vulture

Cathartes aura

40–50% · Likely

Brown Pelican

Pelecanus occidentalis

40–50% · Likely

Spotted Sandpiper

Actitis macularius

40–50% · Likely

Snowy Egret

Egretta thula

40–50% · Likely

Orange-chinned Parakeet

Brotogeris jugularis

40–50% · Likely

⭐ Iconic Species

Pacific Ridley

Lepidochelys olivacea

30–40% · Possible

Black Spiny-tailed Iguana

Ctenosaura similis

80–90% · Very likely

📊 Most Spotted

Green Iguana

Iguana iguana

60–70% · Likely

Rose-bellied Lizard

Sceloporus variabilis

30–40% · Possible

Köhler’s Vine Snake

Oxybelis koehleri

30–40% · Possible

Common House Gecko

Hemidactylus frenatus

30–40% · Possible

American Crocodile

Crocodylus acutus

30–40% · Possible

White-throated Gecko

Gonatodes albogularis

20–30% · Possible

Central American Lyresnake

Trimorphodon quadruplex

20–30% · Possible

Black-necked Centipede Snake

Tantilla armillata

20–30% · Possible

Copper Anole

Anolis cupreus

20–30% · Possible

Aspidoscelis deppei

Aspidoscelis deppii

20–30% · Possible

Central American Boa

Boa imperator

20–30% · Possible

Green Turtle

Chelonia mydas

Insufficient data

📊 Most Spotted

Giant Marine Toad

Rhinella horribilis

40–50% · Likely

Mexican Smilisca

Smilisca baudinii

40–50% · Likely

Milk Frog

Trachycephalus macrotis

20–30% · Possible

Yellow Toad

Incilius luetkenii

10–20% · Possible

Savage's Thin-toed Frog

Leptodactylus savagei

Insufficient data

Dry Forest Toad

Incilius coccifer

Insufficient data

Stauffer's Tree Frog

Scinax staufferi

Insufficient data

Yellow Treefrog

Dendropsophus microcephalus

Insufficient data

Sheep Frog

Hypopachus variolosus

Insufficient data

Turbo White-lipped Frog

Leptodactylus poecilochilus

Insufficient data

Masked Tree Frog

Smilisca phaeota

Insufficient data

Boulenger's Snouted Tree Frog

Scinax boulengeri

Insufficient data

Animal Events

🐢

Olive Ridley Arribada

JulAugSepOctNovDec

In one of the planet's greatest wildlife spectacles, tens to hundreds of thousands of Olive Ridley sea turtles storm ashore together over a handful of nights, hauling up the sand shoulder to shoulder to dig their nests. This synchronized mass nesting, known as an arribada, is the largest of its kind in the world.

Pacific Ridley

Lepidochelys olivacea

30–40% · Possible

🐢

Green & Leatherback Turtle Nesting

JulAugOctDec

Between the great ridley arribadas, green turtles and the immense leatherback — the largest sea turtle on Earth — come ashore alone under cover of darkness to nest on the same beach. Watching a solitary giant heave up the sand and carve out her nest is a quieter, more intimate turtle encounter.

Green Turtle

Chelonia mydas

Insufficient data

Leatherback Sea Turtle

Dermochelys coriacea

Insufficient data

🐦

Coastal & Migratory Bird Season

JanFebMarNovDec

During the northern winter the beach and river mouth fill with resident and migratory birds, from Brown Pelicans plunge-diving for fish to Snowy Egrets stalking the shallows. Overhead, Magnificent Frigatebirds ride the sea breeze on long angular wings, harrying other birds for their catch.

Magnificent Frigatebird

Fregata magnificens

30–40% · Possible

Brown Pelican

Pelecanus occidentalis

40–50% · Likely

Snowy Egret

Egretta thula

40–50% · Likely

Sighting Calendar

Chance of spotting each species, month by month

Species Total

50–60

60–70

50–60

50–60

60–70

50–60

50–60

60–70

50–60

60–70

60–70

60–70

40–50

0–10

20–30

20–30

0–10

0–10

40–50

40–50

40–50

30–40

40–50

20–30

Mantled Howler Monkey

80–90

80–90

70–80

80–90

70–80

90–100

80–90

70–80

70–80

70–80

70–80

80–90

Black Spiny-tailed Iguana

70–80

80–90

80–90

60–70

70–80

80–90

90–100

80–90

60–70

70–80

80–90

80–90

White-nosed Coati

40–50

60–70

50–60

70–80

60–70

70–80

10–20

60–70

50–60

70–80

50–60

40–50

70–80

80–90

60–70

70–80

80–90

70–80

60–70

70–80

60–70

90–100

90–100

80–90

60–70

70–80

70–80

60–70

80–90

60–70

60–70

70–80

60–70

70–80

70–80

70–80

Rufous-backed Wren

60–70

70–80

70–80

70–80

70–80

80–90

60–70

60–70

50–60

80–90

60–70

60–70

40–50

40–50

40–50

50–60

70–80

50–60

80–90

60–70

40–50

40–50

40–50

60–70

Great-tailed Grackle

50–60

70–80

60–70

60–70

70–80

60–70

50–60

40–50

60–70

60–70

60–70

70–80

Variegated Squirrel

50–60

50–60

50–60

60–70

60–70

70–80

60–70

60–70

60–70

10–20

70–80

60–70

Hoffmann's Woodpecker

40–50

60–70

60–70

40–50

60–70

50–60

50–60

60–70

50–60

60–70

60–70

50–60

Black-headed Trogon

50–60

60–70

60–70

50–60

60–70

50–60

60–70

50–60

40–50

60–70

40–50

30–40

Tropical Kingbird

40–50

50–60

50–60

40–50

30–40

30–40

30–40

40–50

50–60

60–70

70–80

60–70

40–50

50–60

40–50

40–50

40–50

40–50

20–30

50–60

50–60

60–70

70–80

40–50

40–50

50–60

40–50

50–60

40–50

40–50

20–30

30–40

20–30

50–60

30–40

60–70

Spotted Sandpiper

40–50

50–60

40–50

30–40

40–50

10–20

20–30

50–60

60–70

60–70

30–40

50–60

Animal Events

🐢 Olive Ridley Arribada

🐢 Green & Leatherback Turtle Nesting

🐦 Coastal & Migratory Bird Season

Sighting Zones

Warm areas are where all species together are recorded most, so they track where people go as much as where animals are. For one species, see the map on its own page.

0.0 ★★★★★ ★★★★★ Good

🐢 Pacific Ridley Arribada at Ostional

🦜

Biodiversity

Good

How rich is the wildlife?

4.3 Global avg

3.9 ★★★★★ ★★★★★

Species by taxon

🦅 Birds

457

🐒 Mammals

166

🦎 Reptiles

82

🐸 Amphibians

22

727 Total Species

841 Global average across 280 parks

27 Threatened 62 Endemic

🔭

Sighting

Very good

How likely to see animals?

3.6 Global avg

3.6 ★★★★★ ★★★★★

🎯

Top-12 Avg Probability

62% Global avg

66%

📊

Coverage (182 species at ≥5% of 727 in the inventory)

24% Global avg

25%

🔀

Taxon variety in top 12 (7 bird, 3 mammal, 2 reptile)

47% Global avg

76%

🔭

Species per 10 outings (distinct species a visitor would meet over 10 outings — effort held equal across parks)

132 Global avg

109

🌟

Iconic-group species (≥15%) (every species from the 19 iconic groups — monkeys, cats, toucans, macaws, sloths, crocodilians… — not just the 4 highlighted above)

14 Global avg

11

⭐

High-prob species (>40%)

26 Global avg

24

Explore Other Parks

Las Baulas Marine National Park

📍 57 km 🐢 Leatherback Turtle Nesting

Las Baulas Marine National Park

🇨🇷 Costa Rica 🌍 #175 Global · 3.5 ★★★★★ ★★★★★ #31 in Central America #82 in Tropical Forest

Palo Verde National Park

📍 57 km 🐦 Jabiru Storks Over Flooded Marshes

Palo Verde National Park

🇨🇷 Costa Rica 🌍 #38 Global · 4.6 ★★★★★ ★★★★★ #4 in Central America #11 in Tropical Forest

Cabo Blanco Absolute Nature Reserve

📍 80 km 🐒 Reliable Monkey Sightings

Cabo Blanco Absolute Nature Reserve

🇨🇷 Costa Rica 🌍 #144 Global · 3.8 ★★★★★ ★★★★★ #26 in Central America #71 in Tropical Forest

Santa Rosa National Park

📍 100 km 🐢 Olive Ridley Arribada

Santa Rosa National Park

🇨🇷 Costa Rica 🌍 #54 Global · 4.4 ★★★★★ ★★★★★ #9 in Central America #19 in Tropical Forest