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APPENDIX B: OFFSHORE VISITORS,

RARE MIGRANTS, AND VAGRANTS

Here we list 103 species reported from Costa Rica as offshore pelagic migrants, rare visitors, and vagrants,

plus potential residents overlooked or unconfirmed in Costa Rica. Some are likely of more regular

occurrence than presently known, especially offshore pelagic species. If encountered, any of these species

should be documented carefully. In a few cases, plate layout allowed some rare species to be incorporated

in the main body of the book; these are mainly species that appear similar to more common and regularly

occurring species (such as Eastern Warbling Vireo vs. Philadelphia Vireo) or species that might be found

by anyone in the field and for which inclusion in the plates may help clarify status (such as Solitary Eagle,

Gray-bellied Hawk).

Two ‘official’ checklists of the birds of Costa Rica may be found online, although details for rare species

in each list do not agree: one compiled by the Unión de Ornitólogos de Costa Rica (Sandoval & Sánchez

2019) and the other by the Comité de Especies Raras y Registros Ornitológicos de Costa Rica (Garrigues

et al. 2018). Our reference to these and other sources was supplemented by review from James R. Zook

and online searches, but we take responsibility for any errors perceived in the following list. Also see

Appendix A for some species that breed on Cocos Island.

P Regular visitor to offshore waters, some rarely ranging nearer shore and encountered on pelagic day

trips from mainland, such as Leach’s Storm Petrel, Swallow-tailed Gull;

V Very rare, sporadic, or potentially overlooked; not usually recorded annually but could be encountered

on occasion, such as Dunlin, Lark Sparrow;

X Exceptional, species with at most 3 records, such as Catesby’s Tropicbird, Maguari Stork;

(Parentheses indicate no substantiated records or reports of presumed wild birds since 2000, such as

Orange-breasted Falcon, White-bellied Emerald);

[Brackets indicate species reported in the literature or eBird, but unconfirmed or without convincing

documentation; here considered hypothetical, such as Short-tailed Shearwater, Golden-crowned Fly­

catcher, Pine Warbler];

(Cocos) indicates species recorded only from Cocos Island.

X(Greater) White-fronted Goose Anser albifrons

XOrinoco Goose Neochen jubata

V(White-faced Whistling Duck Dendrocygna

viduata)

XComb Duck Sarkidiornis sylvicola

(Mallard Anas platyrhynchos)

VWhite-cheeked Pintail Anas bahamensis

XCanvasback Aythya valisineria

VRedhead Aythya americana

[Greater Scaup Aythya marila]

XHooded Merganser Lophodytes cucullatus

XRed-breasted Merganser Mergus merganser

VRuddy Duck Oxyura jamaicensis

XEared Grebe Podiceps [nigricollis] californicus

VGalapagos (Waved) Albatross Phoebastria

irrorata

XAtlantic Yellow-nosed Albatross Thalassarche

chlororhynchos

XBlack-capped Petrel Pterodroma hasitata

XCory’s Shearwater Calonectris [diomedea] borealis

XScopoli’s Shearwater Calonectris [d.] diomedea

XGreat Shearwater Ardenna gravis

VSooty Shearwater Ardenna grisea

[Short-tailed Shearwater Ardenna tenuirostris]

XManx Shearwater Puffinus puffinus

VBlack-vented Shearwater Puffinus opisthomelas

V[Wilson’s Storm Petrel Oceanites oceanicus]

V(Latham’s [White-faced] Storm Petrel

Pelagodroma marina)

PDarwin’s [Band-rumped] Storm Petrel Thalobata

[castro] bangsi 

PGalapagos [Wedge-rumped] Storm Petrel

Halocyptena tethys

PMarkham’s Storm Petrel Hydrobates markhami.

PLeach’s Storm Petrel Hybdrobates leucorhous

XRed-tailed Tropicbird Phaethon rubricauda

(Cocos)

XYellow-billed Tropicbird Phaethon lepturus

(Cocos)

XCatesby’s Tropicbird Phaethon [lepturus] catesbyi

XPeruvian Booby Sula variegata

V[South Polar Skua Catharacta maccormicki]

VBonaparte’s Gull Chroicocephalus philadelphia

XBrown-hooded Gull Chroicocephalus

cirrocephalus

XGray Gull Leucophaeus modestus (Cocos)

XBlack-legged Kittiwake Rissa tridactyla