BirdAnalyst
BBS Route · Pennsylvania · BCR 13

Slippery Rk Bird Survey Route

A standard 50-stop Breeding Bird Survey route. 100 species recorded across 25 survey years, no longer active.

100Species 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 →
25Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →
1970–1994Span
2Observers

Bird Species Found on Pennsylvania Slippery Rk

Top 40 of 100 species by most recent count. Each links to its species trend.

Species recorded on the Slippery Rk 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
Canada GooseAnatidae991994+405%1989
Common GrackleIcteridae961994-43%1972
American RobinTurdidae801994-17%1972
Red-winged BlackbirdIcteridae541994-17%1972
House SparrowPasseridae521994-26%1972
Chimney SwiftApodidae371994+17%1973
House FinchFringillidae301994+0%1987
Mourning DoveColumbidae281994+56%1972
European StarlingSturnidae211994-71%1972
Barn SwallowHirundinidae181994+36%1972
American CrowCorvidae171994+37%1972
Chipping SparrowPasserellidae151994-36%1972
Song SparrowPasserellidae91994-55%1972
Gray CatbirdMimidae81994+67%1972
Northern CardinalCardinalidae61994+21%1972
MallardAnatidae51993+57%1977
Eastern PhoebeTyrannidae41994+25%1974
Scarlet TanagerCardinalidae41990+0%1976
Wood ThrushTurdidae41994+0%1973
Bank SwallowHirundinidae41988+180%1979
Yellow-billed CuckooCuculidae41991+300%1990
Rock PigeonColumbidae31994+92%1972
Indigo BuntingCardinalidae31994-30%1974
Common YellowthroatParulidae31994+27%1972
Brown ThrasherMimidae31992-55%1976
Northern House WrenTroglodytidae31994+180%1972
Savannah SparrowPasserellidae31989+200%1973
White-breasted NuthatchSittidae31988+33%1982
Blue-winged TealAnatidae31985+200%1982
Great Blue HeronArdeidae21994+0%1973
Blue JayCorvidae21994+18%1972
Brown-headed CowbirdIcteridae21994-40%1974
Eastern MeadowlarkIcteridae21993-78%1972
Purple FinchFringillidae21992-25%1982
American GoldfinchFringillidae21994+16%1972
Eastern TowheePasserellidae21994-42%1972
Cedar WaxwingBombycillidae21992+125%1974
Yellow WarblerParulidae21994-67%1972
Green HeronArdeidae21992-20%1977
Belted KingfisherAlcedinidae21990+100%1977

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