Neotropical migratory birds experience variable atmospheric conditions throughout their annual life histories, raising questions about drivers of annual survival. The Southwestern Willow Flycatchers (Empidonax traillii extimus, SWFL) breeding in the Kern River Valley (KRV), California declined over the last 20 years despite breeding and survival parameters that were comparable to other SWFL populations that were stable or increasing in size and management that increased nest success, indicating that non-breeding season mechanisms may be at play. We used a long-term (24-yr) mark-recapture dataset from 617 individually marked flycatchers in the KRV breeding ground to investigate additive and interactive effects of multiple atmospheric conditions in breeding, migration and winter ranges on annual survival to improve our understanding of this decline. Our analyses indicate that increased numbers of months with above normal drought severity on the wintering grounds decreased annual apparent survival, whereas years with increased drought severity on the breeding ground prior to and during the previous season increased survival. An additional subset analysis of the data during a steady decline (2000-2014) revealed that survival decreased in response to increased drought conditions prior to flycatchers arriving on the wintering grounds, with female survival exceeding that of males and unknown sexed birds.

Greater Sage-Grouse (Centrocercus urophasianus; hereafter, “sage-grouse”) populations have declined significantly across the western United States, including in the Bi-State Distinct Population Segment (Bi-State DPS), largely attributed to habitat loss and fragmentation. For the Parker Meadows subpopulation in the Bi-State DPS, landscape changes combined with likely inbreeding depression resulted in rapid population declines during the early 2000s. Thus, translocations were initiated in 2017 to prevent local extirpation. As part of this conservation project, we compared the efficacy of two translocation methods to help inform management decisions that optimize population restoration efforts. We compared whole-brood translocations (females with their broods) and augmented-brood translocations (broods augmented with extra chicks from a donor brood). We evaluated initial chick retention rates and survival estimates within translocated whole-broods and augmented-broods, as well as between donor and non-donor broods within the source population. We also compared habitat selection and survival between resident and translocated broods and created source-sink habitat maps to help guide suitable future release locations. By identifying the most effective translocation method and optimal release locations, we will provide valuable insights for conservation managers aiming to restore sage-grouse populations. These findings are preliminary, subject to change, and provided for best timely science.

Breeding behaviors in birds can influence genetic diversity and so are of interest in the management of endangered species. However, egg dumping (intra-specific egg parasitism), pairing of closely related individuals, and extra-pair copulation are difficult to detect via behavioral observations, and must be corroborated with genetic information. Cooperative breeding behaviors such as helpers-at-the-nest and incubation by more than two adults, as well as other breeding behaviors such as suspected egg dumping, were recently documented in the Threatened Ae‘o (Hawaiian Stilt; Himantopus mexicanus knudseni) on the island of Moloka‘i in the Hawaiian Islands. As these behaviors are rarely observed in Charadriiformes (wading birds), in this study we compared behavioral observations of potential relationships among chicks and adults with genetic relatedness, utilizing reduced-representation sequencing and analysis of SNPs. We observed genetic evidence consistent with egg dumping, potential extra-pair copulation, and inbreeding, but were not able to assess the relatedness of extra-pair adults that contributed to incubation and nest defense. As many of the individuals in this population are color-banded and monitored regularly by local community residents, this study lays a foundation for further studies of behavior and genetic diversity in this recovering species.

Many species rely on acoustic signals for communication, and disruptions to these signals can negatively impact populations. California least terns (Sternula antillarum browni; herafter ‘terns’), a federally listed endangered migratory seabird, are particularly vulnerable, with statewide populations decreasing year over year. One tern nesting colony resides at Vandenberg Space Force Base, within 1 km of space launch complex 2 (SLC-2) operated by Firefly Aerospace. The effects of rocket noise on the vocalizations of this population are unknown. Our objective is to test competing hypotheses (Lombard effect or acoustic adaptation hypothesis) explaining the vocalization response of terns to a loud acoustic event like a rocket launch. In this analysis, we target the Firefly Aerospace Alpha rocket launch on July 3rd, 2024. We deployed 12 Wildlife Acoustics Song Meter SM4TS in March 2024 before terns arrived for nesting. Eight devices were spaced 100 meters apart, and the remaining four were configured in a square with a spacing of twenty-five meters. These devices recorded vocalizations and rocket launch noise from March 2024 to August 2024. Pre- and post-launch vocalization activity, amplitude, and frequencies are compared, and these results will be presented.

Changes in land use following Euro-American colonization resulted in the severe reduction of the endemic Southern California black walnut (Juglans californica) and much of its woodland habitat in Southern California. I will share our research findings on the importance of these woodlands to the larger ecosystem and discuss how ecological research can be intersectional by addressing both conservation and social justice issues. We quantified the availability of trees and large shrubs and the feeding behavior of birds in eight patches of California walnut woodland in Los Angeles County during the spring, summer, and fall periods of 2023. We related habitat features within and adjacent to the eight patches to bird foraging behavior and compared bird feeding patterns relative to tree and shrub availability, documenting 49 species of trees and shrubs (17,904 plant observations) and 49 species of birds (1,009 foraging observations. Total counts of native tree and shrubs (R2kl = 0.30; p <0.10), and native tree and shrub richness (R2kl = 0.64; p <0.001) were positive predictors of the counts of feeding birds. Conversely, building density adjacent to the woodland patches (R2kl = 0.77; p <0.001) and non-native tree and shrub counts (R2kl = 0.71; p <0.001) were negative predictors of the counts of feeding birds. Birds foraged on the western sycamore (Platanus racemosa), coast live oak (Quercus agrifolia), and blue elderberry (Sambucus mexicana) in higher proportion to their availability in the woodlands (ranging from 14% to 68% higher use relative to a plant’s availability). This research was directly inspired by the anti-gentrification efforts of community groups affiliated with Takaape' Washuut Black Walnut Day in Northeast Los Angeles.

The University of California, Davis Wood Duck Nest Box Project, led by Dr. John Eadie, has played a vital role in supporting Wood Duck conservation through 26 years of research and hands-on student involvement. This project has contributed to the recovery of Wood Duck populations in California's Sacramento Valley while providing over 700 undergraduate student interns with practical field experience. Student filmmaker Edilyn Lazo documented the 2024 field season, focusing on the efforts of a monitoring intern crew and master's student Tenaya Russell. The resulting 12-minute film explores the impact of artificial nesting sites on Wood Duck conservation and highlights the intersection of research, student engagement, and wildlife preservation. In a 5-minute presentation preceding the screening, Edilyn will discuss the project's significance, its legacy of fostering student involvement in real-world conservation, and the collaborative student efforts behind the documentary's production.