BBS Route · Colorado · BCR 16
Delta Bird Survey Route
A standard 50-stop Breeding Bird Survey route. 127 species recorded across 47 survey years, still active.
127Species Recorded
47Years Surveyed
1973–2021Span
4Observers
Bird Species Found on Colorado Delta
Top 40 of 127 species by most recent count. Each links to its species trend.
| History | ||||||
|---|---|---|---|---|---|---|
| Mourning Dove | Columbidae | 20 | 2021 | -41% | 1975 | |
| Warbling Vireo | Vireonidae | 19 | 2021 | +185% | 1975 | |
| American Robin | Turdidae | 16 | 2021 | +29% | 1975 | |
| Common Raven | Corvidae | 14 | 2021 | +78% | 1976 | |
| Pine Siskin | Fringillidae | 13 | 2021 | +39% | 1975 | |
| Rock Wren | Troglodytidae | 13 | 2021 | -35% | 1975 | |
| Bushtit | Aegithalidae | 12 | 2021 | +567% | 1983 | |
| Horned Lark | Alaudidae | 11 | 2021 | +9% | 1975 | |
| Chipping Sparrow | Passerellidae | 11 | 2021 | -42% | 1975 | |
| Western Tanager | Cardinalidae | 10 | 2021 | +46% | 1975 | |
| Bewick's Wren | Troglodytidae | 8 | 2021 | +240% | 1976 | |
| Spotted Towhee | Passerellidae | 8 | 2021 | +33% | 1977 | |
| Violet-green Swallow | Hirundinidae | 8 | 2021 | +122% | 1976 | |
| Turkey Vulture | Cathartidae | 7 | 2012 | +233% | 1991 | |
| Ash-throated Flycatcher | Tyrannidae | 7 | 2021 | +122% | 1975 | |
| Black-billed Magpie | Corvidae | 7 | 2021 | -32% | 1975 | |
| Green-tailed Towhee | Passerellidae | 7 | 2021 | -35% | 1975 | |
| Virginia's Warbler | Parulidae | 7 | 2021 | -33% | 1975 | |
| Ruby-crowned Kinglet | Regulidae | 7 | 2021 | +317% | 1976 | |
| Gray Flycatcher | Tyrannidae | 7 | 2021 | +300% | 1978 | |
| Woodhouse's Scrub-Jay | Corvidae | 7 | 2021 | +183% | 1977 | |
| Brewer's Blackbird | Icteridae | 7 | 2021 | +89% | 1977 | |
| Blue-gray Gnatcatcher | Polioptilidae | 6 | 2021 | +0% | 1975 | |
| Mountain Bluebird | Turdidae | 6 | 2019 | +22% | 1975 | |
| Hermit Thrush | Turdidae | 6 | 2021 | +90% | 1976 | |
| Red Crossbill | Fringillidae | 6 | 2019 | -23% | 2012 | |
| Dusky Flycatcher | Tyrannidae | 5 | 2021 | +80% | 1975 | |
| Lark Sparrow | Passerellidae | 4 | 2021 | +71% | 1976 | |
| Orange-crowned Warbler | Parulidae | 4 | 2021 | +233% | 1982 | |
| American Crow | Corvidae | 4 | 2021 | -40% | 1976 | |
| Cinnamon Teal | Anatidae | 4 | 1998 | n/a | n/a | |
| Pinyon Jay | Corvidae | 3 | 2021 | -8% | 1975 | |
| House Finch | Fringillidae | 3 | 2021 | -30% | 1975 | |
| Northern House Wren | Troglodytidae | 3 | 2021 | +75% | 1975 | |
| White-crowned Sparrow | Passerellidae | 3 | 2017 | +50% | 1978 | |
| Black-headed Grosbeak | Cardinalidae | 3 | 2021 | +30% | 1976 | |
| Steller's Jay | Corvidae | 3 | 2021 | +133% | 1981 | |
| Juniper Titmouse | Paridae | 3 | 2021 | +82% | 1981 | |
| Lesser Goldfinch | Fringillidae | 3 | 2015 | +0% | 1992 | |
| Western Meadowlark | Icteridae | 2 | 2021 | +20% | 1975 |
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. A route is a sample, not a census.