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USGS2028

Migration ecology and stopover population size of Red Knots Calidris canutus rufa at Mingan Archipelago after exiting the breeding grounds

Populations of migratory birds present unique conservation challenges given the often vast distances separating critical resources throughout the annual cycle. Migration areas close to the breeding grounds represent a link between two key stages of the annual cycle, and understanding migration ecology as birds exit the breeding grounds may be particularly informative for successful conservation. We studied migration phenology and stopover ecology of an endangered subspecies of the Red Knot Calidris canutus rufa at a migration area relatively close to its breeding range. Using mark-recapture/resight data and a Jolly-Seber model for open populations, we described the arrival and departure schedules, stopover duration, and passage population size at the Mingan Archipelago, Quebec, Canada. Red Knots arrived at the study area in two distinct waves of birds separated by approximately 22 days. Nearly 30% of the passage population arrived in the first wave of arrivals during 15–18 July, and approximately 22% arrived in a second wave during 8–11 August. The sex-ratio in the stopover population at the time of the first wave was slightly skewed toward females, whereas the second wave was heavily skewed toward males. Because males remain on the breeding grounds to care for young, this may reflect successful breeding in the year of our study. The estimated stopover duration (population mean) was 11 days (95% credible interval: 10.3–11.7 days), but stopover persistence was variable throughout the season. We estimated a passage population size of 9,450 birds (8,355–10,710), a minimum estimate for reasons related to the duration of our sampling. Mingan Archipelago is thus an important migration area for this endangered subspecies and could be a priority in conservation planning. Our results also emphasize the advantages of mark-recapture/resight approaches for estimating migration phenology and stopover persistence.

Quebec↗
USGS2027

Ground failure resulting from earthquake ground motions

The ground failure resulting from an earthquake, at all scales, is ultimately controlled by the details of near-surface earthquake ground motions, the spatially distributed mechanical characteristics of surface materials and how the two interact. This chapter introduces the aspects of ground-motion seismology that are most relevant to the triggering of different types of ground failure, such as landslides and liquefaction. In particular, the chapter focuses on different sources of local modification (e.g. amplification) of earthquake ground motions in the shallow subsurface, known as site effects. The chapter ends with an overview of the controls on, general spatial patterns of, and approaches to regional modelling of the manifestation of ground failure that may be triggered by an earthquake.

Book chapter↗
USGS2026

Distribution, abundance, and habitat characteristics of Coastal Cactus Wrens ( Campylorhynchus brunneicapillus ) in San Diego County, California—2025 data summary

Executive Summary We surveyed for coastal Cactus Wren ( Campylorhynchus brunneicapillus ) in 498 established plots in San Diego County, California, in 2025, encompassing 4 genetic clusters (Otay, Lake Jennings, Sweetwater/Encanto, and San Pasqual). Of the 498 plots, 372 have been surveyed every year starting in 2020. Two surveys were completed at each plot between March 1 and July 31. Cactus Wrens were detected in 220 plots (44 percent of plots). In plots that have been consistently surveyed since 2020, Cactus Wrens were detected in 35 percent of plots, similar to 2024 (34 percent), 2021 (35 percent), and 2020 (35 percent), and higher than in 2023 (26 percent) and 2022 (30 percent). Across all survey plots we detected 184 Cactus Wren territories in 2025. We documented 107 territories in plots that have been consistently surveyed since 2020, which is similar to the number of territories in 2024 (106) and 2020 (108), more than we documented in 2022 (93) and 2023 (85), but slightly less than the peak in 2021 (113). Across all survey plots the number of territories increased from 2024 to 2025 in the San Pasqual genetic cluster, increased slightly in the Lake Jennings cluster, decreased slightly in the Sweetwater/Encanto genetic cluster and remained the same in the Otay genetic cluster. At least 83 percent of Cactus Wren territories were occupied by pairs, and 100 fledglings were observed in 2025. We observed three banded Cactus Wrens in 2025. Adult birds ranged from 6 to 9 years old and occupied the same territories as in previous years. Banding of Cactus Wrens ceased in 2019 and as a result we have a very low number of banded wrens remaining in the population, which makes it difficult to detect movement of wrens between genetic clusters. We detected no movement of banded Cactus Wrens between genetic clusters in 2025. Vegetation at Cactus Wren survey plots was dominated by coastal sage scrub shrubs, such as California sagebrush ( Artemisia californica ), California buckwheat ( Eriogonum fasciculatum ), and lemonade berry ( Rhus integrifolia ). Cactus Wrens preferentially selected plots dominated by California buckwheat in the Otay genetic cluster and avoided plots dominated by lemonade berry and jojoba ( Simmondsia chinensis ). Cactus Wrens also appeared to prefer plots dominated by broom baccharis ( Baccharis sarothroides ) while avoiding plots dominated by California sagebrush in the Lake Jennings cluster. No definitive signs of fungal pathogens were observed on cactus within and around survey plots. Blue elderberry ( Sambucus mexicana ) was detected at 43 percent of plots, and Cactus Wrens preferentially occupied more plots with elderberry than were available. Very little dead or unhealthy cactus was observed within all survey plots, and Cactus Wrens preferentially occupied plots with less dead cactus while occupying plots with unhealthy cactus in proportion to its availability. Eighty-nine percent of plots had more than 5 percent of cactus crowded or overtopped by vines and shrubs, and Cactus Wren occupied plots in proportion to the degree of shrub and vine crowding or overtopping. Just over half of the plots had greater than 5 percent non-native annual cover, with Cactus Wrens preferentially occupying plots with less non-native cover.

California↗
USGS2026

The National Wildlife Disease Database

The National Wildlife Disease Database (NWDD) is a national information hub that integrates wildlife disease data across jurisdictions to guide natural resource management and deliver early warnings of unusual events and emerging threats, strengthening public health preparedness and protecting the agricultural economy.

Fact Sheet↗
USGS2026

Evolution of summit magma pressure during the 2018 caldera collapse at Kılauea volcano

We utilized geodetic data from the 16 May to 4 August 2018 caldera collapse sequence to refine the geometries and pressure evolution of two summit reservoirs at Kīlauea volcano: the shallower Halema‘uma‘u (HMM) and deeper South Caldera (SC) reservoirs. We modeled magma reservoirs as pressurized spheroidal cavities and constrained reservoir geometries with Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar displacements. Inverting high-rate GPS and borehole tilt time series recovered time-dependent reservoir pressure changes and caldera ring fault shear stress. During the collapse sequence, the HMM reservoir accommodated episodic, co-collapse pressure increases of 1.9 MPa (median) and a net 5.8 MPa (median) decrease. Simultaneously, the SC reservoir underwent monotonic depressurization of 6.7 MPa (median). Negligible co-collapse pressure changes in the SC reservoir imply it was not exclusively supplying magma to the eruption vent. These results provide a coherent view of magma reservoir pressure evolution during the 2018 eruption.

Hawaii↗
USGS2026

Slip tendency and dilation tendency of Quaternary faults in the Great Basin region, Arizona, California, Idaho, Nevada, Oregon, Utah, and Wyoming

This report presents the results of slip tendency and dilation tendency analysis of Quaternary faults in the Great Basin region, in the states of Arizona, California, Idaho, Nevada, Oregon, Utah, and Wyoming. This effort was undertaken as part of two studies: the U.S. Department of Energy Geothermal Technologies Office-funded Innovative Geothermal Exploration through Novel Investigations of Undiscovered Systems (INGENIOUS) project, which is a multidisciplinary, multi-institution effort to develop new methodologies and best practices to accelerate the discovery of new, commercially viable hydrothermal resources; and the U.S. Geological Survey Geothermal Resources Investigations Project. The goal of this work is to identify faults and fault segments that are appropriately oriented to be stress-loaded for slip or to dilate under the ambient stress conditions. Both conditions may make such faults more likely to host permeability and fluid flow relative to other faults in the region. Slip tendency and dilation tendency were calculated for all fault segments in the study area from the U.S. Geological Survey Quaternary Fault and Fold Database. Results demonstrate that faults with high slip tendency and dilation tendency are common in the Great Basin region. The areas containing many high slip tendency and dilation tendency fault segments are associated with high strain rates. These areas also host a relatively high proportion of the known hydrothermal systems. This indicates that faults with high slip tendency and dilation tendency in areas with high strain-rate are potentially most prospective for hosting hydrothermal systems. The database published in coordination with this report contains the slip tendency and dilation tendency results data, including the fault geometry and stress data used to calculate these quantities, for both the Great Basin study area and the smaller INGENIOUS study area.

Arizona, California, Idaho, Nevada, Oregon, Utah, ↗
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