Genomic insights into isolation of the threatened Florida crested caracara (Caracara plancus).

We conducted a population genomic study of the crested caracara (Caracara plancus) using samples (n = 290) collected from individuals in Florida, Texas, and Arizona, United States. Crested caracaras are non-migratory raptors ranging from the southern tip of South America to the southern United States, including a federally protected relict population in Florida long thought to have been isolated since the last ice age. Our objectives were to evaluate genetic diversity and population structure of Florida's apparently isolated population and to evaluate taxonomic relationships of crested caracaras at the northern edge of their range. Using DNA purified from blood samples, we conducted double-digest restriction site associated DNA sequencing and sequenced the mitochondrial ND2 gene. Analyses of population structure using over 9,000 SNPs suggest that two major clusters are best supported, one cluster including only Florida individuals and the other cluster including Arizona and Texas individuals. Both SNPs and mitochondrial haplotypes reveal the Florida population to be highly differentiated genetically from Arizona and Texas populations, whereas, Arizona and Texas populations are moderately differentiated from each other. The Florida population's mitochondrial haplotypes form a separate monophyletic group, while Arizona and Texas populations share mitochondrial haplotypes. Results of this study provide substantial genetic evidence that Florida's crested caracaras have experienced long-term isolation from caracaras in Arizona and Texas and thus, represent a distinct evolutionary lineage possibly warranting distinction as an Evolutionarily Significant Unit (ESU) or subspecies. This study will inform conservation strategies focused on long-term survival of Florida's distinct, panmictic population.

Molecular detection of bacteria in the families Rickettsiaceae and Anaplasmataceae in northern crested caracaras (Caracara cheriway).

Bacterial pathogens of the families Anaplasmataceae and Rickettsiaceae are often spread to humans or other animals from bites from infected arthropod hosts. Recently, an increasing number of studies have implicated migratory birds in the circulation of these pathogens through the spread of arthropod vectors. However, few studies have examined the potential for resident bird populations to serve as reservoirs for these zoonoses. In this study, we used nested PCRs of the GroESL and 17 kDa genes to screen for Anaplasmataceae and Rickettsiaceae, respectively, in a resident population of the northern crested caracara (Caracara cheriway) from Florida (n=55). Additionally, a small number (n=6) of captive individuals from Texas were included. We identified one individual (1.64%) positive for Rickettsia felis and one (1.64%) positive for Ehrlichia chaffeensis; both these individuals were from Florida. Presence of these pathogens demonstrates that these birds are potential hosts; however, the low prevalence of infections suggests that these populations likely do not function as an ecological reservoir.

Prevalence of antibodies to West Nile virus and other arboviruses among Crested Caracaras (Caracara cheriway) in Florida.

We documented the antibody prevalence to three arboviruses, St. Louis encephalitis virus (SLEV), eastern equine encephalitis virus (EEEV), and West Nile virus (WNV), in Crested Caracaras (Caracara cheriway; n = 80) in Florida from 2007 to 2008. Antibody prevalence to WNV was higher (9%) than for the other viruses. Most seropositive birds were adults (< or =3 yr of age), with 55% of adults testing positive for antibodies to at least one virus. Adults were significantly more likely to have antibodies to WNV than nonadults (P<0.001). Prevalence of SLEV and EEEV antibodies among Crested Caracaras was 3% for each virus, and three adult caracaras had indistinguishable anti-flavivirus antibodies. The susceptibility of Crested Caracaras to adverse effects of WNV, SLEV, or EEEV infection remains unknown; however, we observed that some free-ranging individuals survived infection and successfully fledged young. Knowledge of arboviral infection among Florida's Crested Caracara, which is both state and federally threatened, is valuable considering increasing pressure on this population from rapid and extensive habitat alterations.

Leucocytozoon toddi and Haemoproteus tinnunculi (Protozoa: Haemosporina) in the Chimango caracara (Milvago chimango) in southern Chile

Two species of blood protozoans were identified from blood smears collected from 15 specimens of the Chimango caracara (Milvago chimango) on Isla Grande de Chiloé in southern Chile. These included Leucocytozoon toddi in 13 birds, including all 5 of the 4-6 week old nestlings examined, and 8 of the subadults or adults. One of the nestlings also had a dual infection of L. toddi and Haemoproteus tinnunculi. These are the first reports of blood parasites from M. chimango