Bird Declines are Reaching a Tipping Point
In developing the Road to Recovery approach to reversing avian declines, we start by asking “Which species do we need to work on first?” in order to identify specific limiting factors and causes of declines and to support the teams of scientists and practitioners dedicated to recovering their populations. Which species are most likely to slip into Endangered Species Act Threatened and Endangered status or head toward extinction or extirpation in the near future if no conservation action is taken? For which species is it imperative that we conduct the science needed to identify the specific causes of decline—and develop proactive strategies for species recovery before listing is imminent?
Scientists for the Road to Recovery initiative have identified 90 On-Alert bird species in need of strong and immediate scientific action to pinpoint causes of declines and to support practitioners dedicated to recovering their populations. These birds have high vulnerability to extinction and steep population declines as described below, with 50% or more of their populations lost during 1970–2019. Of the 90 On-Alert species, 70 are Tipping Point species that either show continued or recent accelerated declines that if continued could lead to the loss of 50% or more of their populations in the next 50 years (high urgency) or have perilously small populations, high threats, and insufficient monitoring data (presumed high urgency/data deficient).
We relied first on data already available in the Avian Conservation Assessment Database (ACAD)—a database maintained by Partners in Flight (PIF) and housed at Bird Conservancy of the Rockies. We categorized the species based on high vulnerability to extinction, steep population decline, and high urgency, as described below.
High Vulnerability to Extinction: 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. Species with CCS ≥ 16 show high vulnerability across multiple factors and constitute the Red Watch List.
Steep Population Decline: Based on the latest long-term population trend data for 529 U.S./Canada species (Rosenberg et al. 2019), 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 are assigned a Population Trend (PT) score = 5 in the ACAD and include many Watch List species. Trend data have been updated through 2019 for the R2R analysis.
Urgency: To assess urgency, we examined the most recent population trajectories for each species based on the most recent analysis of BBS and other survey data. This analysis mirrors the survey data used to assess trends for 529 species in Rosenberg et al. (2019), have been updated through 2019, and includes a complete re-analysis of shorebird trend data by Paul Smith (unpublished 2021). By comparing long-term trends (back to 1970 for most species; to 1980 for shorebirds) with the most recent population trajectories (defining “recent” as 3 bird species generations), and examining trend estimates in light of the 2022 State of the Birds composite results, we identified species in two urgency categories:
Species of High Urgency: Species with large long-term population loss (> 50%), continued or accelerated recent declines, and a “half-life” < 50 years when projecting forward the most recent 3-generation trend.
Presumed High Urgency/Data Deficient: Poorly monitored species that are believed to be declining and 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. These species are marked with an asterisk in the list below.
On-Alert and Tipping Point Species
Scientists for the Road to Recovery initiative have identified 90 On-Alert bird species in need of strong and immediate scientific action to pinpoint causes of declines and to support practitioners dedicated to recovering their populations.
Tipping Point Species (in red) are on a trajectory to lose another 50% of their populations in the next 50 years (41 species), or already have perilously small populations and continue to face high threats, but lack sufficient monitoring data (29 species, indicated with an asterisk).
Great Black-backed Gull
Pilot Species Working Groups
With generous support from the Knobloch Family Foundation, Road to Recovery is able to begin supporting the recovery of Tipping Point species with four pilot projects. The purpose of these projects is to provide a proof of concept for advancing both biological and social science targeted at identifying and addressing causes of species declines.