BirdAnalyst
BBS Route · Texas · BCR 19

Mertzon Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 86 species recorded across 37 survey years, no longer active.

86Species RecordedSpecies recordedDistinct species detected on standard-protocol BBS runs here across all years on record — a measure of survey breadth, not a complete checklist.Full methodology →
37Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1967–2019Span
7Observers

Bird Species Found on Texas Mertzon

Top 40 of 86 species by most recent count. Each links to its species trend.

Species recorded on the Mertzon route.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →History
Ash-throated FlycatcherTyrannidae282019+525%1969
Turkey VultureCathartidae272019+76%1969
Cassin's SparrowPasserellidae212019-84%1969
Painted BuntingCardinalidae202019+20%1969
Bell's VireoVireonidae20201912×1969
Brown-headed CowbirdIcteridae182019-39%1969
Northern CardinalCardinalidae182019-11%1969
Cliff SwallowHirundinidae152016+39%2012
Northern MockingbirdMimidae142019-66%1969
Lark SparrowPasserellidae132019-71%1969
Cave SwallowHirundinidae132019+10%1994
Bewick's WrenTroglodytidae112019-71%1969
Western MeadowlarkIcteridae102002-43%1971
Black-throated SparrowPasserellidae92019-68%1969
Blue GrosbeakCardinalidae92018+100%1969
Great Blue HeronArdeidae82012+233%1979
House SparrowPasseridae72019+8%1971
Mourning DoveColumbidae62019-81%1969
Orchard OrioleIcteridae62019+14%1969
Golden-fronted WoodpeckerPicidae42019-73%1969
Grasshopper SparrowPasserellidae42015+0%1974
Chipping SparrowPasserellidae42010+0%2007
KilldeerCharadriidae32007-61%1969
Northern BobwhiteOdontophoridae32019-40%1969
Scissor-tailed FlycatcherTyrannidae32019-25%1969
Common RavenCorvidae32011-29%1969
Lesser GoldfinchFringillidae32011+60%1969
PyrrhuloxiaCardinalidae32019+36%1972
Barn SwallowHirundinidae32019+70%1974
Carolina ChickadeeParidae32002+50%1979
White-winged DoveColumbidae32019+33%2013
Scaled QuailOdontophoridae22019-84%1969
Wild TurkeyPhasianidae22006+400%1969
Horned LarkAlaudidae22016-82%1969
Rufous-crowned SparrowPasserellidae22010+0%1972
Canyon TowheePasserellidae22019+14%1969
Rock PigeonColumbidae22002+0%1968
Swainson's HawkAccipitridae22015-50%1972
VerdinRemizidae22013+25%1972
Blue-gray GnatcatcherPolioptilidae22017+0%1986

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. A route is a sample, not a census.