The Road to Recovery Species Lists

I. Species on the Precipice of Endangerment

In developing the Road to Recovery approach to reversing avian declines, we started by asking “Which species do we need to work on first?” in terms of identifying specific limiting factors and causes of declines. To address this question, we relied first on data already available in the Avian Conservation Assessment Database (ACAD)—a database created and maintained by Partners in Flight (PIF) and housed at Bird Conservancy of the Rockies. We identified a group of 73 species that exhibited a combination of high vulnerability to extinction, steep population decline, and high urgency, as described below.

High Vulnerability to Extinction (High Concern):  Vulnerability in the ACAD is assessed by carefully scoring a series of independent factors (Population Size, Breeding and Nonbreeding Distribution, Threats, and Trend) that are combined into a single Combined Conservation Score (CCS) that ranges from 4 to 20 (see the ACAD Handbook for a thorough description). Species that meet a threshold of CCS > 13 are considered to be highly vulnerable and are placed on the ACAD Watch List.

Steep Population Decline:  Based on the latest long-term population trend data for 529 US/Canada species (Rosenberg et al. 2019 in Science), we identified those species that are estimated to have lost 50% or more of their total adult breeding population since 1970. This group of species were assigned a Population Trend (PT) score = 5 in the ACAD and include many Watch List species and also a set of Common Species in Steep Decline that do not meet Watch List CCS criteria.

High Urgency: To assess urgency, we used the “half-life” metric first developed by Stanton et al. (2016) and applied to landbirds in the 2016 PIF Landbird Conservation Plan. The half-life metric projects the most recent 10-year population trend forward in time to estimate when that population is likely to decline by an additional 50% if environmental conditions remain the same and no conservation action is taken. Adam Smith (unpublished) applied this metric to the 529 species analyzed for the Science paper. Species are considered High Urgency if their projected half-life based on the 10-year trajectory is less than 50 years. Note that some species exhibit high urgency even though they were not previously identified as Watch List species or Common Species in Steep Decline—these species should be monitored closely to detect a further deterioration in conservation status.

We included an initial 39 species with sufficient data to meet all three criteria of High Vulnerability, Steep Decline, and High Urgency—that are not currently listed as Endangered or Threatened in the U.S.—in what we are calling the Road to Recovery Urgency List. These are species most likely to slip into ESA T&E status or head toward extinction or extirpation in the near future if no conservation action is taken and for which it is imperative that we conduct the science needed to identify and address the specific causes of decline.

However, there are a number of additional species with small populations and high threats for which we lack the long-term monitoring data needed to quantitatively assess the magnitude of decline or the urgency. Thus we designate an additional category…

Presumed Urgency/Data Deficient: Poorly-monitored species that are believed to be declining have been assigned PT scores of 5 or 4 in the ACAD via expert opinion; for some of these, the population trend is completely unknown. This additional set of species are defined by a combination of small population size (PS = 4,5) and high threats (TB or TN = 4,5) and have expert-assigned PT scores of 5,4, or 3. This set of Presumed Urgency/Data Deficient species adds an additional 34 species to the Road to Recovery Urgency List for a total of 73 species in need of targeted science to identify and address specific causes of decline.

II. Recovering Avifaunal Abundance

While vitally important for conserving the full diversity of US/Canada bird species and preventing future extinctions or T&E listings, the above list of 73 species accounts for only 6% of the total loss of abundance across the US/Canadian avifauna. To bring back 3 billion birds and restore abundance, we need to address the threats and limiting factors affecting these widespread yet declining species as well. As with the R2R urgency species described above, in most cases we don’t know the specific limiting factors and causes of declines for these more common species that contribute most to the total loss of abundance. For example, why is one of the most common birds at winter feeders, Dark-eyed Junco, declining?

Loss of Total Abundance: Using the estimated median population loss since 1970 from Rosenberg et al. (2019), we call attention to the 56 native species that have lost at least 1 million individuals from the US/Canada breeding population and have also indicated high urgency based on most recent 10-yr trajectory (urgency score = 4,5). Of these, 22 species meet the Class I Urgency criteria outlined above, so this group would add an additional 34 species to the overall urgency/abundance list. Note that the top 10–12 species in this group account for half of the total loss of abundance across the US/Canada region.

Biome-Specific Loss of Abundance: Because restoring abundance of widespread common species may require regionally specific actions, we have also identified those species that contribute most to the loss of abundance within each biome. For example, the loss of Black-throated Sparrows accounts for < 1% of the continental loss of abundance, but 31% of the loss of abundance within the Aridlands biome.

NB: The R2R team, in collaboration with PIF Science, is still refining its analysis and inclusion criteria, including refinements in the calculation of the half-life metric, so the R2R lists should be regarded as DRAFT lists at present.

Sources Cited:

Partners in Flight. 2020a. Avian Conservation Assessment Database, version 2020. Available at

Rosenberg, K.V., A.M. Dokter, P.J. Blancher, J.R. Sauer, A.C. Smith, P.A. Smith, J.C. Stanton, A. Panjabi, L. Helft, M. Parr, and P.P. Marra. 2019. Decline of the North American Avifauna. Science 10.1126/science.aaw1313.

Stanton J.C., B.X. Semmens, P.C. McKann, T. Will, and W.E. Thogmartin. 2016. Flexible risk metrics for identifying and monitoring conservation-priority species. Ecological Indicators 61, Part 2:683–692.

DRAFT R2R Urgency List (10/7/20)

Urgency List (Data Supported Species):

  1. King Eider *
  2. Greater Sage-Grouse
  3. Eastern Whip-poor-will *
  4. Black Swift
  5. Chimney Swift *
  6. Broad-tailed Hummingbird *
  7. Rufous Hummingbird *
  8. Allen’s Hummingbird *
  9. King Rail
  10. American Golden-Plover
  11. Mountain Plover
  12. Whimbrel
  13. Hudsonian Godwit
  14. Ruddy Turnstone *
  15. Pectoral Sandpiper
  16. Semipalmated Sandpiper *
  17. Short-billed Dowitcher
  18. Lesser Yellowlegs *
  19. Least Tern
  20. Black Skimmer
  21. Yellow-billed Loon
  22. Olive-sided Flycatcher *
  23. Pinyon Jay *
  24. Yellow-billed Magpie
  25. Bendire’s Thrasher
  26. Sprague’s Pipit *
  27. Evening Grosbeak *
  28. Chestnut-collared Longspur *
  29. McCown’s Longspur *
  30. Bachman’s Sparrow
  31. Black-chinned Sparrow
  32. LeConte’s Sparrow *
  33. Baird’s Sparrow *
  34. Bobolink *
  35. Golden-winged Warbler
  36. Virginia’s Warbler *
  37. Connecticut Warbler *
  38. Cerulean Warbler *
  39. Grace’s Warbler *

Urgency List (Data Deficient Species):

  1. Lesser Prairie-Chicken
  2. Yellow Rail
  3. Black Rail
  4. Snowy Plover
  5. Bristle-thighed Curlew
  6. Kittlitz’s Murrelet
  7. Scripps’s Murrelet
  8. Guadalupe Murrelet
  9. Craveri’s Murrelet
  10. Whiskered Auklet
  11. Red-legged Kittiwake
  12. Ivory Gull
  13. Heermann’s Gull
  14. Elegant Tern
  15. Black-footed Albatross
  16. Short-tailed Albatross
  17. Townsend’s Storm-Petrel
  18. Ashy Storm-Petrel
  19. Band-rumped Storm-Petrel
  20. Murphy’s Petrel
  21. Black-capped Petrel
  22. Fea’s Petrel
  23. Parkinson’s Petrel
  24. Black-vented Shearwater
  25. Audubon’s Shearwater
  26. Reddish Egret
  27. Green Parakeet
  28. Red-crowned Parrot
  29. Bicknell’s Thrush
  30. Black Rosy-Finch
  31. Brown-capped Rosy-Finch
  32. Cassia Crossbill
  33. Seaside Sparrow
  34. Saltmarsh Sparrow

*  range-wide loss in abundance > 1 million

Loss of Abundance & High Urgency:
* (species in this category included above)

  1. Long-tailed Duck
  2. Northern Bobwhite
  3. Scaled Quail
  4. Chuck-will’s-widow
  5. Dunlin
  6. Thick-billed Murre
  7. Mew Gull
  8. Herring Gull
  9. Least Flycatcher
  10. Loggerhead Shrike
  11. Horned Lark
  12. Bank Swallow
  13. Rock Wren
  14. Cactus Wren
  15. Arctic Warbler
  16. Varied Thrush
  17. Sage Thrasher
  18. Bohemian Waxwing
  19. Pine Siskin
  20. Cassin’s Sparrow
  21. Grasshopper Sparrow
  22. Black-throated Sparrow
  23. Field Sparrow
  24. Brewer’s Sparrow
  25. Fox Sparrow
  26. Dark-eyed Junco
  27. Golden-crowned Sparrow
  28. White-throated Sparrow
  29. Savannah Sparrow
  30. Eastern Meadowlark
  31. Rusty Blackbird
  32. Brewer’s Blackbird
  33. Common Grackle
  34. Blackpoll Warbler