Author ORCID Identifiers
Dylan Osterhaus:
https://orcid.org/0000-0002-9044-1090
Allison Salas:
https://orcid.org/0009-0007-5818-0509
Abigail Lawson:
https://orcid.org/0000-0002-2799-8750
Timothy Wright:
https://orcid.org/0000-0003-2859-5360
Jeanne Fair:
https://orcid.org/0000-0002-3377-6134
Martha Desmond:
https://orcid.org/0000-0002-1952-5435
Description
Many birds are migratory, and this life history strategy allows for maximized access to seasonally abundant resources and favorable climates. However, migration exposes birds to threats and stressors, resulting in high mortality during migration. Anthropogenic landscape alterations and climate change have intensified threats, and mass mortality events linked to extreme weather are more common in recent decades. Documenting mass mortality is critical for predicting future occurrences and implementing effective conservation. Here, we describe a mortality event that occurred throughout New Mexico, USA in fall 2020. Carcasses began appearing in the region in mid-August, during a period of extreme heat and drought. Following an extreme cold weather event on September 8–9th, the number of carcasses increased dramatically and expanded throughout the state. In total, we collected 628 carcasses comprising 58 species within Doña Ana and Otero Counties in New Mexico. Necropsy determined emaciation was the cause of death for 74.6% of carcasses. Live birds captured during the period of peak mortality (n = 223) were in similarly poor condition. This event provides a striking example of how multiple types of extreme stressors, in this case widespread drought and unseasonal cold, coincided with a mortality event, indicating a possible synergistic relationship between these factors and the mass mortality. Mortality events are likely to increase in frequency with intensifying climate change. Establishment of networks of biologists and researchers could improve our ability to identify and communicate developing mortality events, organize data collection, and improve understanding of the causes and consequences of mortality. The data and code included herein can be used to recreate the analyses included in this manuscript.
Document Type
Dataset
Publication Date
2026
Publisher
New Mexico State University Library
Keywords
avian migration, bird mortality, climate change, extreme weather, mass mortality, migration mortality
Disciplines
Biodiversity | Ornithology | Other Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology
Department / Organizational Unit
Fish, Wildlife, and Conservation Ecology; Biology
Copyright Statement
© Author(s), reuse allowed according to Creative Commons license
License for Reuse
This work is licensed under a Creative Commons Attribution 4.0 International License.
Funder
NMSU Natural Resources Career Track Program funded by USDA Hispanic Serving Institutions Program; NMSU Avian Migration Program funded by the USDA Hispanic Serving Institutions Program; U.S. Hatch Act
Grant / Award Number
2015-38422-30947, 2022-77040-37638
Recommended Citation
Osterhaus, Dylan M.; Salas, Allison J.; Cutler, Patricia L.; Weisenberger, Mara E.; Mower, Kerry; Lawon, Abigail J.; Wright, Timothy F.; Fair, Jeanne M.; and Desmond, Martha J., "Data from: Mass Mortality of Avian Migrants in New Mexico, USA, that Coincided with an Extreme Weather Event" (2026). Fish, Wildlife, & Conservation Ecology: Datasets. 2.
https://digitalcommons.nmsu.edu/fish-wildlife-conservation-data/2
Included in
Biodiversity Commons, Ornithology Commons, Other Ecology and Evolutionary Biology Commons, Terrestrial and Aquatic Ecology Commons