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OLD WORLD SPARROWS (PASSERIDAE; 1 SPECIES) Old World family, one
species introduced to New York in 1850 and has spread widely in North and Central America.
Ages/sexes differ; resembles adult within 1–2 months, following complete molt.
HOUSE SPARROW Passer domesticus 14–15cm. Human commensal found in
urban areas, adjacent farmland, along highways at truck stops, gas stations. In
pairs or small flocks, sometimes mixing with other birds but usually apart. Feeds
mainly on ground, often perches on buildings, utility poles; groups roost in dense
shrubbery. Handsome male distinctive; head and breast pattern veiled with paler
edgings in fresh plumage, bill mostly pale in nonbr. condition. Female rather
plain but no similar species in Costa Rica. Juv. resembles female, soon attains
adult appearance. SOUNDS: Varied, mostly rather tuneless chirps and chips, dry
chatters, churring calls. STATUS: Fairly common and widespread, especially in dri-
er areas, least numerous in humid tropical lowlands; mainly below 1500m. (Worldwide; native to Eurasia.)
MUNIAS (ESTRILDIDAE; 1 SPECIES) Small seed-eating ‘finches’ of Old World
origin. Populations derived from escaped cagebirds or releases are becoming established locally
in New World. Ages differ, sexes similar; attain adult appearance within a few months.
TRICOLORED MUNIA Lonchura malacca 10–11cm. Small handsome ‘finch’ of
seeding grassy fields, rice fields, irrigation ditches, edges of cane fields. Often in
groups, in same areas as native seedeaters and migrant buntings, although flocks
often keep apart from other species; rather direct ‘barreling’ flight suggests small
compact House Sparrow. Adult (sexes similar) distinctive, with bold plumage pat-
tern, small size; juv. rather plain but note large pale bill, rather short and graduated
tail, voice. SOUNDS: Usually rather quiet; flight call a burry to twangy overslurred
nasal byehh, singly or in short series. STATUS: Uncommon to fairly common but
local on Pacific slope and in nw. lowlands, to 1500m in Central Valley; first re-
corded Costa Rica in 1999 and range still expanding. (Native to India.)
FINCHES (FRINGILLIDAE; 12 SPECIES) Fairly large, almost worldwide family of
small, often colorful seed- and fruit-eating birds. Ages/sexes usually differ, juv. often like
female; attain adult appearance within 1st year. Calls and songs notably varied, sometimes
including mimicry.
YELLOW-BELLIED SISKIN Spinus xanthogastrus 10–11cm. Highland oak
forest and edge, adjacent clearings and second growth, weedy pastures with
scattered trees, hedgerows. Singles, pairs, or small groups feed from low in
seeding grasses to high in tree canopy. Note big yellow wing patch, cf. Lesser
Goldfinch. SOUNDS: Short metallic whistled notes, such as kleéih; low gruff
cheh, at times in short series. Song a rapid jangling medley, often with repetition
of notes and phrases; in bursts of 2–10 secs strung together with short breaks,
or prolonged to 20 secs or more; averages higher, more metallic, but also more
melodic, less buzzy than Lesser Goldfinch. STATUS: Uncommon and nomadic
in Central and Talamanca Mts. especially Pacific slope, mainly 800–2100m, locally to 3000m. Widely
reduced in numbers by trapping for cagebird trade. (Costa Rica to S America.)
LESSER GOLDFINCH Spinus psaltria 9.5–10.5cm. Open and semi-open
country with scattered trees, hedgerows, gardens, weedy fields. Usually in small
flocks, feeding from low in seeding grasses to high in tree canopy. Note white wing
patch, cf. Yellow-bellied Siskin, lack of yellow forehead patch cf. male euphonias,
which favor humid lowlands. Juv. resembles female, with buffy wingbars, soon like
adult. SOUNDS: High, slightly whiny whistles, often downslurred or overslurred,
such as teeuu, about 0.5 secs; nasal chíeh. Song a varied, rapid jangling and
burbling warble, can include buzzy trills, occasional wheezy phrases, 2–20 or more
secs; averages buzzier, less jangling than Yellow-bellied Siskin. STATUS: Uncommon
to fairly common in Central and Talamanca Mts., adjacent Central Valley, mainly 1200–3000m; since
2010s, scarce and local in s. Pacific and nw. lowlands. (Mexico and w. US to nw. S America.)