I spent the first three months of 2005 in Costa Rica - January 1st to March 30th to be exact. My primary place of residence was in the town of Playa Azul near Tarcoles. Many birders who have been to Costa Rica have either stayed at or been to the Tarcol Lodge which is right across the street from where I stayed. A place called The Herman Institute. It was about a 12 and half second walk from my place to the popular mud flats that were overlooking the mouth of the Tarcoles River. The river is the largest in Costa Rica if not all of Central America. The flats attract birds such as [Least, Western, Semipalmated and Spotted Sandpipers, Willet, Whimberel, Short-billed Dowitcher, Black-bellied (Grey),Semipalmated and Wilson's Plover, Black-necked Stilt, Northern Jacana, Great Blue Heron, Snowy and Great Egret, White Ibis, Roseate Spoonbill, Wood Stork and Black Vulture]. In the Mangroves in the background there are [Yellow-headed Caracara, Mangrove Black-hawk, Yellow-crowned Night-heron, Turkey and Black Vultures]. On the river banks there are [Green, Belted, Ringed and Amazon Kingfishers, Yellow-crowned Night-heron, Great Blue, Little Blue and Tricolored Heron, Yellow-headed and Crested Caracara, Anhinga, Neotropic Cormorant, Black-bellied Whistling-duck, Northern Jacana and Purple Gallinule].
Aside from the estuarine habitat I just described there are two other types of habitat In the Playa Azul area: Mangrove forests and dry tropical forest. There's also farmland if you count that as habitat. There are several Mangrove tours in the area. The best tour I had was run by a man named Luis. On the tour we saw [Ringed, Green, American Pygmy and Amazon Kingfishers. Barn, Southern Rough-winged, Cave, Cliff, and Mangrove Swallow, Yellow-crowned Night-heron, Great blue, Little blue, tricolored, Boat-billed and Bare-throated Tiger-heron, Roseate Spoonbill, White Ibis, Wood Stork, Great, Snowy and Cattle Egret, Northern Jacana, Purple Gallinule, on foot hikes to the snad tip of the Tarcoles River there are Royal, Elegant and Sandwich Tern, Brown Pelican, Magnificent Frigatebird, Laughing Gull and Black Skimmer, other birds include Mangrove Warbler (a handsome subspecies of Yellow Warbler) Yellow-naped Parrot, Orange-fronted Parakeet, Scarlet Macaw, Bright-rumped Attila, Sulphur-bellied, Streaked, Panama, Social and Boat-billed Flycatchers, Great Kiskadee, Tropical Kingbird, Tropical Pewee, Rufous-browed Pepper-shrike, Cinnamon Becard, Prothonotary Warbler, Northern Waterthrush, American Redstart, Plumbeous Kite, Short-tailed Hawk, Mangrove Black-hawk, Mangrove Vireo, Mangrove Hummingbird, Mangrove Cuckoo, Olivaceous Woodcreeper, Rufous-tailed Hummingbird and Hoffmann's Woodpecker].
Many of those species can also be found on walks around town or on trails in dry forest and adjacent mangroves. For new comers worried about dangerous animals on the trails don't worry the only harmful animals are the ants that protect the Acacia trees. As long as you don't touch the trees you'll be fine. No large spiders and only one snake, a Neotropical Coachwhip which unless your a mouse is completely harmless. Other bird on these trails not mentioned in the list above include [Turquoise-browed Motmot, Squirrel Cuckoo, Black-headed and Violaceous Trogon, Scrub Euphonia, Scrub and Lesser Greenlet, Greenish and Yellow-bellied Elaenia, Great Crested Flycatcher, Brown-crested Flycatcher, Dusky-capped Flycatcher, Barred Antshrike, Crane Hawk, Collared Forest-falcon, Gray Hawk, Roadside Hawk, Groove-billed Ani, Rufous-naped Wren, Plain Wren, Clay-colored Robin, White-throated Magpie-jay, Pacific Screech-owl, Black-and-white Owl, Ferruginous Pygmy-owl, Lineated Woodpecker, Blue-gray Tanager, Palm Tanager, Streak-headed Woodcreeper, Inca Dove, Ruddy Ground-dove, White-tipped Dove, Red-lored and White-fronted Parrot, Orange-chinned Parakeet, Lesser Nighthawk, Common Pauraque, Scaly-throated Hummingbird, Magenta-throated Woodstar, Steely-vented Hummingbird, Green-breasted Mango, White-necked Puffbird (don't get your hopes up it was there for a few days then gone), Rose-throated Becard, Common Tody-Flycatcher, Slate-headed Tody-tyrant, Tropical Gnatcatcher, Grey-crowned Yellowthroat, Great-tailed Grackle, Red-legged Honeycreeper, Stripe-headed Sparrow, for the tourists who visit during the northern winter when migrants are in town there is Baltimore Oriole, Prothonotary Warbler, Northern Waterthrush, American Redstart, Tennessee Warbler, Chestnut-sided Warbler, Summer Tanager, Ruby-throated Hummingbird, Painted Bunting (the males were hard to spot)and migrating north from South America was Piratic Flycatcher].
a=Abundant: all over the place or reliably in the right place
c=common: saw them on a most bird walks or usually in right place
fc=fairly common: saw them on some bird walks
uc=uncommon: saw one or two on bird walks in right habitat
r=rare: saw only one the entire time
Least Sandpiper a
Western Sandpiper c
Semipalmated Sandpiper c
Spotted Sandpiper c
Willet c
Whimberel c
Short-billed Dowitcher fc
Black-bellied(Grey) Plover fc
Semipalmated Plover fc
Wilson's Plover fc
Black-necked Stilt fc
Northern Jacana c
Great Blue Heron a
Snowy Egret fc
Great Egret fc
White Ibis c
Roseate Spoonbill c
Wood Stork c
Black Vulture a
Yellow-headed Caracara a
Mangrove Black-hawk c
Yellow-crowned Night-heron a
Turkey Vulture a
Green Kingfisher fc
Belted Kingfish uc
Ringed Kingfisher fc
Amazon Kingfisher fc
Little Blue Heron fc
Tricolored Heron c
Crested Caracara uc
Anhinga c
Neotropic Cormorant c
Black-bellied Whistling-duck uc
Purple Gallinule uc
Barn Swallow a
Southern Rough-winged Swallow a
Cave Swallow c
Cliff Swallow c
Mangrove Swallow c
Boat-billed Heron c
Bare-throated Tiger-heron fc
Cattle Egret fc
Royal Tern c
Elegant Tern r
Sandwich Tern c
Brown Pelican c
Magnificent Frigatebird c
Laughing Gull fc
Black Skimmer c
Mangrove Warbler c
Yellow-naped Parrot c
Orange-fronted Parakeet c
Scarlet Macaw c
Bright-rumped Attila uc (easily heard)
Sulphur-bellied Flycatcher fc
Streaked Flycatcher fc
Panama Flycatcher uc
Social Flycatcher fc
Boat-billed Flycatchers fc
Great Kiskadee a
Tropical Kingbird a
Tropical Pewee fc
Rufous-browed Pepper-shrike fc
Cinnamon Becard c
Prothonotary Warbler c
Northern Waterthrush c
American Redstart fc
Plumbeous Kite fc
Short-tailed Hawk fc
Mangrove Black-hawk c
Mangrove Vireo uc
Mangrove Hummingbird fc
Mangrove Cuckoo fc
Olivaceous Woodcreeper r
Rufous-tailed Hummingbird a
Hoffmann's Woodpecker a
Turquoise-browed Motmot fc
Squirrel Cuckoo fc
Black-headed Trogon c
Violaceous Trogon fc
Scrub Euphonia c
Scrub Greenlet uc
Lesser Greenlet uc
Greenish Elaenia fc
Yellow-bellied Elaenia fc
Great Crested Flycatcher fc
Brown-crested Flycatcher fc
Dusky-capped Flycatcher uc
Barred Antshrike c
Crane Hawk uc
Collared Forest-falcon uc
Gray Hawk fc
Roadside Hawk uc
Groove-billed Ani a
Rufous-naped Wren a
Plain Wren r
Clay-colored Robin a
White-throated Magpie-jay uc
Pacific Screech-owl r
Black-and-white Owl r
Ferruginous Pygmy-owl c
Lineated Woodpecker c
Blue-gray Tanager a
Palm Tanager c
Streak-headed Woodcreeper c
Inca Dove a
Ruddy Ground-dove c
White-tipped Dove fc
Red-lored Parrot uc
White-fronted Parrot fc
Orange-chinned Parakeet c
Lesser Nighthawk fc
Common Pauraque uc (easily heard)
Scaly-throated Hummingbird fc
Magenta-throated Woodstar uc
Steely-vented Hummingbird uc
Green-breasted Mango fc
White-necked Puffbird r
Rose-throated Becard uc
Common Tody-Flycatcher fc
Slate-headed Tody-tyrant fc
Tropical Gnatcatcher fc
Grey-crowned Yellowthroat r
Great-tailed Grackle a
Red-legged Honeycreeper fc
Stripe-headed Sparrow uc
Baltimore Oriole c
Tennessee Warbler fc
Chestnut-sided Warbler fc (a lot more common in Carara NP)
Summer Tanager fc
Ruby-throated Hummingbird uc
Painted Bunting uc
Piratic Flycatcher fc