Widespread Lead Exposure in Golden Eagles Captured in Montana

Aspergillosis in 41 wild bird species in the eastern United States: a 22-year retrospective review

Aspergillosis is the most commonly and widely reported fungal infection in birds. Disease development is often secondary to stressors that cause immunocompromise, and it is typically regarded as a disease of captivity. We retrospectively evaluated data from 133 birds diagnosed with aspergillosis at the Southeastern Cooperative Wildlife Disease Study from 2001-2023 to assess diversity and relative frequency across avian taxa, gross and histologic lesion patterns, and comorbidities. Of 10 taxonomic orders represented, Charadriiformes (shorebirds; n = 35) and Accipitriformes (raptors; n = 32) were most common. Among them, the laughing gull (Leucophaeus atricilla; n = 20) and bald eagle (Haliaeetus leucocephalus; n = 14) were infected most commonly. Gross lesions were most frequent in lung (n = 80), air sac (n = 71), or celomic cavity lining (n = 42). Four distinct gross lesion patterns were identified: 1) tan caseous plaques (n = 106), 2) hollow masses lined with mold (n = 26), 3) red pulmonary nodules (n = 15), and 4) necrotic brown plaques (n = 3). Histologically, fungal hyphae were most common in lung (n = 107) and air sac (n = 49). Comorbidities were diagnosed in 67 birds with a spectrum of viral (n = 19), bacterial (n = 11), parasitic (n = 6), other fungal (n = 4), and non-infectious (n = 50) causes. Six birds each were diagnosed with highly pathogenic avian influenza or salmonellosis. Twenty-two birds were emaciated. Free-ranging birds are susceptible to myriad stressors that can predispose them to the development of aspergillosis.

Lead poisoning of raptors: state of the science and cross-discipline mitigation options for a global problem

Lead poisoning is an important global conservation problem for many species of wildlife, especially raptors. Despite the increasing number of individual studies and regional reviews of lead poisoning of raptors, it has been over a decade since this information has been compiled into a comprehensive global review. Here, we summarize the state of knowledge of lead poisoning of raptors, we review developments in manufacturing of non-lead ammunition, the use of which can reduce the most pervasive source of lead these birds encounter, and we compile data on voluntary and regulatory mitigation options and their associated sociological context. We support our literature review with case studies of mitigation actions, largely provided by the conservation practitioners who study or manage these efforts. Our review illustrates the growing awareness and understanding of lead exposure of raptors, and it shows that the science underpinning this understanding has expanded considerably in recent years. We also show that the political and social appetite for managing lead ammunition appears to vary substantially across administrative regions, countries, and continents. Improved understanding of the drivers of this variation could support more effective mitigation of lead exposure of wildlife. This review also shows that mitigation strategies are likely to be most effective when they are outcome driven, consider behavioural theory, local cultures, and environmental conditions, effectively monitor participation, compliance, and levels of raptor exposure, and support both environmental and human health.

Lead exposure and source attribution for a mammalian scavenger before and after a culling program

Lead-based ammunition is a significant source of environmental lead and threatens species that scavenge lead-shot carcasses, particularly in areas with intensive shooting. With the impacts of lead on avian scavengers well established, there is increasing focus on the effects of lead on mammalian scavengers. We investigated lead exposure in a morphologically specialized mammalian scavenger, the Tasmanian devil (Sarcophilus harrisii), by analyzing their blood lead levels (BLLs) before and after a marsupial culling program using linear mixed effects models. We compared lead isotope signatures in devil blood to those in the culling ammunition to inform potential source attributions. We sampled 23 devils before culling and 15 after culling, finding no significant difference in mean BLLs pre and post-culling. However, devils captured closer to forestry coupes where culling had occurred had higher BLLs, and a greater proportion of devils displayed elevated BLLs post-culling (33 % compared to 18 % pre-culling). The highest BLL (7.93 μg/dL) was found in a devil post-culling and this individual had lead isotope signatures that matched the ammunition samples analyzed, suggesting the individual was exposed to lead from scavenging on culled carcasses. While 18 % of the devil blood lead samples had isotope signatures consistent with the ammunition samples, most were measurably different, indicating other sources of lead in the landscape. BLLs in our study landscape were similar to published BLLs for wild devils across Tasmania. That said, lead isotope signatures in the blood of individual devils sampled both before and after culling shifted closer to those of ammunition samples post-culling. Our results indicate that while some individual devils may have been exposed to lead from culling, most devils in the landscape did not show evidence of recent exposure. However, even low lead levels can adversely impact wildlife health and immunity, a particular concern for devils, a species endangered by disease.