No abstract

Fatality monitoring at wind projects requires carcass detection trials to adjust fatality estimates for the proportion of fatalities not found. However, detection trials vary greatly in metric, duration, carcass monitoring schedule, species, number placed, state of decomposition, whether placed within or outside search areas, and other factors. We introduce a new approach for estimating fatalities by quantifying overall detection rates rather than separate rates for searcher detection error and carcass persistence, and by leaving placed and found fatality carcasses undisturbed throughout monitoring. We placed 2 fresh‐frozen bird carcasses weekly at random sites within fatality search areas and on randomized days Monday–Friday at Sand Hill and Santa Clara wind projects, Altamont Pass Wind Resource Area, California, USA. To estimate detection rates, we used logit regression to fit detection outcomes on body mass, which served as an axis of similitude between placed trial carcasses and fatality finds. Adjusted carcass placement rates among species detected by searchers regressed on true placement rates with a slope of 1.0 so long as sufficient numbers of trial carcasses were placed, thus validating our approach as an unbiased estimator. Our approach generally estimated lower fatality rates than did conventional approaches, the latter of which demonstrated biases in searcher detection rates and carcass persistence rates whether based on proportion of carcasses remaining or mean days to removal. Our approach also revealed detection errors that highlight the difficulty of finding and identifying the remains of dead animals, and which warrant routine reporting. Despite averaging only a 5‐day search interval on intensively grazed annual grasslands where ground visibility was usually high, our experienced fatality monitors averaged 4.3 searches/first carcass detection, failed to detect 25% of 75 species represented by placed carcasses, and misidentified carcasses to species among 44% of species detected. Estimates of time since death also suffered bias and large error. Our approach more realistically simulates carcass detection probabilities associated with fatality monitoring, is less costly, facilitates hypothesis testing, eliminates multiple sources of error and bias suspected of conventional methods, and enables quantification of errors in estimated time since death, species identifications, and false negative findings. © 2018 The Wildlife Society.

Plasmodium (Novyella) homopolare, a newly described Plasmodium species, was found in a wide range of Passeriformes species in California, USA, and Colombia. This parasite infected more than 20% of the sampled bird community (N = 399) in California and was found in 3.6% of birds sampled (N = 493) in Colombia. Thus far, it has been confirmed in North and South America where it is present in numerous species of migratory and resident birds from six families. Based on 100% matches, or near-100% matches (i.e., ≤2-nucleotide difference), to DNA sequences previously deposited in GenBank, this parasite is likely also distributed in the Eastern USA, Central America, and the Caribbean. Here, we describe the blood stages of P. homopolare and its mtDNA cytochrome b sequence. P. homopolare belongs to the subgenus Novyella and can be readily distinguished from the majority of other Novyella species, primarily, by the strictly polar or subpolar position of meronts and advanced trophozoites in infected erythrocytes. We explore possible reasons why this widespread parasite has not been described in earlier studies. Natural malarial parasitemias are usually light and co-infections predominate, making the parasites difficult to detect and identify to species when relying exclusively on microscopic examination of blood films. The combined application of sequence data and digital microscopy techniques, such as those used in this study, provides identifying markers that will facilitate the diagnosis of this parasite in natural avian populations. We also address the evolutionary relationship of this parasite to other species of Plasmodium using phylogenetic reconstruction.

BackgroundThe role of vectors in the transmission of avian malaria parasites is currently understudied. Many studies that investigate parasite-vector relationships use limited trapping techniques and/or identify potential competent vectors in the field in such ways that cannot distinguish between an infected or infectious vector. Without the use of multiple trapping techniques that address the specific biology of diverse mosquito species, and without looking at the infection status of individual mosquitoes, it is not possible to make dependable conclusions on the role of mosquitoes in the transmission of avian malaria parasites.MethodsWe conducted two years of mosquito collections at a riparian preserve in California where a wide diversity of species were collected with multiple trap types. We hypothesized that competent mosquito species can influence the distribution and diversity of avian malaria parasites by acting as a compatibility filter for specific Plasmodium species. To determine the infection status of all individual mosquitoes for Plasmodium species/lineages, amplification within the cytochrome b gene was carried out on over 3000 individual mosquito thoraxes, and for those that tested positive we then repeated the same process for abdomens and salivary glands.ResultsOur data show heterogeneity in the transmissibility of Plasmodium among ornithophillic mosquito species. More specifically, Culex stigmatosoma appears to not be a vector of Plasmodium homopolare, a parasite that is prevalent in the avian population, but is a vector of multiple other Plasmodium species/lineages.ConclusionsOur results suggest that conclusions made on the role of vectors from studies that do not use different mosquito trapping methods should be re-evaluated with caution, as we documented the potential for trapping biases, which may cause studies to miss important roles of specific mosquito species in the transmission of avian malaria. Moreover, we document heterogeneity in the transmission of Plasmodium spp. by mosquitoes can influence Plasmodium diversity and prevalence in specific locations to Plasmodium-vector incompatibilities.

Diurnal raptors in the order Accipitriformes are commonly parasitized with Leucocytozoon spp., and the prevalence and intensity of parasitemia are often high. However, for raptors in Falconiformes, several studies have reported relatively low prevalences (1 % or less) of Leucocytozoon spp. Leucocytozoon parasite pathogenicity has been documented in falcons, but little is known about the diversity, prevalence, and phylogenetic relationships among Leucocytozoon species in these predatory birds. The research reported here combines molecular and microscopic techniques to identify and describe Leucocytozoon parasites in Falco sparverius sparverius, the American kestrel, and place those parasites into a phylogenetic context with leucocytozoids previously found in other diurnal raptors (Accipitriformes), owls (Strigiformes), passerines (Passeriformes), and other bird species. Of 35 American kestrels sampled, 13 birds (37.1 %) were found by PCR to harbor the DNA lineage of a novel species, Leucocytozoon californicus. No other Leucocytozoon parasite lineages were identified in our sample. Phylogenetic analysis revealed that this parasite clusters more closely with leucocytozoids found in owls and passerines than it does with leucocytozoids found in birds of the genera Buteo and Accipiter of the order Accipitriformes. This is the first described species of Leucocytozoon that parasitizes diurnal raptors in which gametocytes develop exclusively in roundish host blood cells. It is also the first Leucocytozoon species that is described and named in birds of the Falconiformes, in which, for unclear reasons, leucocytozoids are significantly less prevalent and less diverse than in raptors with a similar behavioral ecology belonging to the Accipitriformes.