BirdAnalyst
Species · Texas · BBS 2025 Release · 1966–2024

Northern Harrier Population Trend in Texas

All statesGeneralists

Northern Harrier in Texas has collapsed: down 79% on the route-weighted index since 1969.

-79%Since 1969TrendPercent 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 →
59Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
47YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Harrier Trends in TexasNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Northern Harrier has collapsed in Texas: down 79% on the route-weighted index since 1969.

Northern Harrier Population Forecast in Texas

If the recent trend holds, Northern Harrier in Texas is projected to stay roughly flat through 2028, near 0.02 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±73.5%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.02Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0995% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±73.5%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Northern Harrier in Texas is projected to stay roughly flat through 2028, near 0.02 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±73.5%, with 100% of held-out values landing inside the 95% band.19672028
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20240.020.000.09
20250.020.000.09
20260.020.000.09
20270.020.000.09
20280.020.000.09

Northern Harrier Survey Routes in Texas

Routes recording Northern Harrier in Texas.
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 →
Plains1019931971
Gruver420162005
Zapata219761976
Catarina219951979
Peach Creek219911991
Cottonwood219981983
Cornudas219731973
Slaughter219751970
Texline220211982
Rachal119681968
Agua Nueva119731973
Marathon120052004
Randado119931968
Mirando City119731973
Encinal119841984
Vanderbilt119761970
George West119711971
Danbury119951967
Lockhart119861976
Lone Oak119991993
Gause119851985
Valley Spgs119941976
San Saba120092002
Kosse120142009
Chinquapin120112003

Northern Harrier Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.