Geology topics

Timothy F. Wright

Publications and source records attributed to Timothy F. Wright.

3 recordsLinked to original sources

USGS2026

Mass mortality of avian migrants in New Mexico, USA, that coincided with an extreme weather event

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 8–9 th , 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.

New Mexico↗

USGS2025

Maintenance of genetic diversity despite population fluctuations in the lesser prairie-chicken (Tympanuchus pallidicinctus)

Assessments of genetic diversity, structure, history, and effective population size ( N e ) are critical for the conservation of imperiled populations. The lesser prairie-chicken ( Tympanuchus pallidicinctus ) has experienced declines due to habitat loss, degradation, and fragmentation in addition to substantial population fluctuations with unknown effects on genetic diversity. Our objectives were to: (i) compare genetic diversity across three temporally discrete sampling periods (2002, 2007-2010, and 2013-2014) that are characterized by low or high population abundance; (ii) examine genetic diversity at lek and lek cluster spatial scales; (ii) identify potential bottlenecks and characterize genetic structure and relatedness; and (iii) estimate the regional N e . We analyzed 194 samples across the shinnery oak prairie region of eastern New Mexico and western Texas using 13 microsatellite loci. Mean heterozygosity, allelic richness, and inbreeding coefficient were not significantly different between discrete sampling periods, suggesting that this population has maintained its genetic diversity across the sampled population fluctuations. We did not detect genetic structure using multiple Bayesian clustering approaches. Furthermore, there was no support for recent genetic bottlenecks, and we estimated that the N e ranged from 229.5 ( p crit = 0.05, 95% CIs = 121.2-1023.1) to 349.1 ( p crit = 0.02, 95% CIs = 176.4-2895.2) during our final sampling period (2013-2014). Although we provide evidence for gene flow within this region, continued habitat loss and fragmentation that leads to population declines and isolation could increase the risk of genetic consequences. Continued monitoring of genetic diversity and increasing available habitat that supports robust populations of lesser prairie-chickens may improve the likelihood of the species' persistence.

New Mexico, Texas↗

USGS2025

Nocturnal flight call monitoring reveals in-flight behavioral alteration by avian migrants in response to artificial light at night

The world in which birds evolved to migrate has been drastically altered in the Anthropocene by artificial light. Sources of light such as urban centers or bright upward-facing lights attract migrants, altering their behavior, especially during inclement weather, often leading to mortality. Seemingly less extreme sources, such as pole-mounted floodlighting, ubiquitous throughout much of the world, have received comparatively less study, and migrant responses to such sources are poorly understood. We studied migrant behavior in relation to light at White Sands Missile Range (New Mexico, USA) by recording nocturnal flight calls at sites with and without lights during non-inclement weather. We collected 103,424 h of recordings and detected 2,851,863 calls over three fall migration seasons. We assessed how temporal, weather, and lighting variables explain variability in call rates between light and dark sites, and examined how different taxonomic groups behave in relation to light. Contrary to predictions, call rates were higher at dark sites than at light sites, and this difference was strongest early in the migration season. We found illuminated sites with a greater proportion of shielded lights, or with lights of higher dominant wavelengths (warmer color temperatures), had higher call rates (closely resembling dark sites) than other light sites, indicating that these factors may reduce impact to migrants. Our taxonomic analyses revealed consistent differences in call rate between light and dark sites for warblers, but no difference for most sparrows. Our findings indicate that lights alter behavior, but the use of “bird-friendly” lighting strategies may reduce this impact.

New Mexico↗