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HOW TO USE THIS BOOK

Area and Species Covered

In this guide to field identification we cover bird species found regularly in mainland Costa Rica, on

inshore islands, and over marine waters that can be reached comfortably within a day trip (out to about

50km, or 30 miles, from shore). Oceanic birds of far offshore waters that few people get to visit are not

included, and neither are very rare and vagrant species unlikely to be seen in Costa Rica (for completeness,

these are listed in the appendices). In a few cases, such as when a rare species is similar to a regularly

occurring one, we have included rare and poorly known species on the plates to encourage clarification

of status; in some cases, plate design considerations influenced the inclusion or omission of rarer species.

Costa Rican species, plus those found in neighboring countries, are covered in the recent Birds of Central

America (Vallely & Dyer 2018), which serious students should consult for further information. Our

baseline taxonomy is that of IOC (Gill et al. 2021), except for oceanic birds, where we follow Howell &

Zufelt (2019). Our cutoff date for species coverage and inclusion is December 2021.

Format

The inside front cover and first three pages comprise pictorial contents to help you get to the right group

of birds. Putting a bird into the correct group of species is an important first step in any identification

process—if you are trying to identify a duck by looking among hawks, well, as they say, ‘You can’t get

there from here.’ Birds are arranged in a user-friendly field-guide sequence (basically, waterbirds, then

landbirds) following Howell et al. (2012) rather than in a phylogenetic order, which is often unsuited to

field identification (Yoon 2009).

Plates

We have tried to group species on plates by similarity in appearance integrated with shared geographic

distribution and habitat—thus, similar species likely to be found together are usually on the same plate

or on adjacent plates. Species on a plate are shown at the same scale, except in a few cases where a line

divides the plate into different scales; this should be obvious by consulting the lengths given in the facing-

page text.

When different ages and sexes are shown, images for a species are arranged with juveniles and immatures

on the left, adults on the right (usually females, then males). An image with no label for age or sex indicates

simply an ‘adult’ bird in which sexes look similar (many first-year songbirds are not distinguishable from

adults after molting out of their briefly held juvenile plumage). When shown, juveniles and immatures are

labeled as such, as are males and females. Well-defined seasonal plumages (mainly for northern migrants)

are often followed by month spans to indicate when these plumages are typically seen.

Family and Genus Accounts

Each family, plus some genera and other species groups, starts with a short account summarizing features

common to the family or group. The number of regularly occurring species in each family is noted in

parentheses; a plus sign (+) indicates additional species in that family have been recorded in Costa Rica,

noted in the appendices.

Species Accounts

These start with English and scientific names, plus length (and sometimes wingspan) in cm; length is bill

tip to tail tip, measured from museum specimens laid on their back with no undue stretching applied. An

asterisk (*) preceding the species name refers you to taxonomic comments in Appendix C.

The use of parentheses in an English or scientific name indicates an alternative name, such as Charming

(Beryl-crowned) Hummingbird, where the more informative name Beryl-crowned Hummingbird is

sometimes used, as by Stiles & Skutch (1989); or Tangara (Thraupis) palmarum for Palm Tanager, where

some authors place this species in the genus Tangara, others in the genus Thraupis. Because names are

changing so frequently we have used parentheses only for what we consider the most widely known

(or sometimes more appropriate) names. For example, Smoky-brown Woodpecker has been transferred

among four (!) different genera in recent years, and different authorities still place it in at least two genera.