A blood-based multi-biomarker approach reveals different physiological responses of common kestrels to contrasting environments.

The increase of urbanization and agricultural activities is causing a dramatic reduction of natural environments. As a consequence, animals need to physiologically adjust to these novel environments, in order to exploit them for foraging and breeding. The aim of this work was to compare the physiological status among nestling common kestrels (Falco tinnunculus) that were raised in nest-boxes located in more natural, rural, or urban areas in a landscape with a mosaic of land uses around Rome in Central Italy. A blood-based multi-biomarker approach was applied to evaluate physiological responses at multiple levels, including antioxidant concentrations, immunological functions, genotoxicity, and neurotoxicity. We found lower concentrations of glutathione and GSH:GSSG ratio values and higher proportions of monocytes in urban birds compared to the other areas. We also found higher DNA damage in rural compared to urban and natural krestels and inhibition of butyrylcholinesterase activity in urban and natural birds compared to rural area. Finally, we found similar values among study areas for respiratory burst, complement system, bactericidal capacity, and plasma non-enzymatic antioxidant capacity. These results suggest that (i) city life does not necessarily cause physiological alterations in kestrels compared to life in other habitats, and (ii) environmental pressures are likely to differ in typology and intensity across habitats requiring specific responses that a multi-biomarker approach can help to detect. Further studies are needed to assess which factors are responsible for the physiological differences among city, rural, and natural birds, and whether these differences are consistent across time and space.

Reduced ectoparasite load, body mass and blood haemolysis in Eurasian kestrels (Falco tinnunculus) along an urban-rural gradient.

Urbanisation is proceeding at an alarming rate which forces wildlife to either retreat from urban areas or cope with novel stressors linked to human presence and activities. For example, urban stressors like anthropogenic noise, artificial light at night and chemical pollution can have severe impacts on the physiology of wildlife (and humans), in particular the immune system and antioxidant defences. These physiological systems are important to combat and reduce the severity of parasitic infections, which are common among wild animals. One question that then arises is whether urban-dwelling animals, whose immune and antioxidant system are already challenged by the urban stressors, are more susceptible to parasitic infections. To assess this, we studied nestlings of Eurasian kestrels (Falco tinnunculus) in Vienna, Austria, during 2015 and 2017. We measured biomarkers of innate immune function, oxidative stress and body mass index and ectoparasite infection intensity in 143 nestlings (from 56 nests) along an urban gradient. Nestlings in more urbanised areas had overall fewer ectoparasites, lower haemolysis (complement activity) and lower body mass index compared to nestlings in less urbanised areas. None of the other immune or oxidative stress markers were associated with the urban gradient. Despite some non-significant results, our data still suggest that kestrel nestlings experience some level of reduced physiological health, perhaps as a consequence of exposure to more urban stressors or altered prey availability in inner-city districts even though they had an overall lower ectoparasite burden in these heavily urbanised areas.

Falcons From the United Arab Emirates Infected With Chlamydia psittaci/C abortus Intermediates Specified as Chlamydia buteonis by Polymerase Chain Reaction.

Chlamydiaceae are obligate intracellular bacteria with a broad host range. Several studies have found chlamydial species that are genetically intermediate between Chlamydia psittaci and Chlamydia abortus in various avian species. One of these intermediate Chlamydia species, found in a red-shouldered hawk (Buteo lineatus), was recently classified as a new species Chlamydia buteonis. This newly described Chlamydia species has, so far, only been reported in hawks exhibiting clinical signs of conjunctivitis, dyspnea, and diarrhea. In the present study, fecal samples of 5 gyrfalcons (Falco rusticolus), 3 gyr/peregrine falcon hybrids (Falco rusticolus × Falco peregrinus), and 15 falcons of unknown species presented to falcon clinics on the Arabian Peninsula were shipped to the Vetsuisse Faculty, University of Zurich (Zurich, Switzerland), for examination for the presence of Chlamydiaceae. A step-wise diagnostic approach was performed to identify the chlamydial species involved. Chlamydiaceae were detected in 21/23 falcons by a family-specific real-time quantitative PCR (qPCR). Further identification with a 23S ribosomal RNA-based microarray assay and 16S conventional PCR and sequencing yielded inconclusive results, indicating the presence of an intermediate Chlamydia species. Because none of the falcons tested positive for Chlamydia psittaci by specific qPCR, all 23 samples were subjected to a Chlamydia buteonis-specific qPCR, which was positive in 16/23 samples. Detailed information regarding clinical history was available for 8 falcons admitted to a falcon clinic in Dubai, United Arab Emirates. Six of those birds that were presented to the clinic because of loss of performance and poor general condition, including vomiting and diarrhea, were positive for C buteonis. In 2 birds without clinical disease signs admitted for a routine health examination, 1 was positive for C buteonis, and 1 was negative. It is yet unknown whether Chlamydia buteonis causes disease in birds, but the findings in this study indicate that Chlamydia buteonis may be an infectious pathogen in falcon species.

Isolation and characterization of microsatellite loci in merlins (Falco columbarius) and cross-species amplification in gyrfalcons (F. rusticolus) and peregrine falcons (F. peregrinus).

Merlins, Falco columbarius, breed throughout temperate and high latitude habitats in Asia, Europe, and North America. Like peregrine falcons, F. peregrinus, merlins underwent population declines during the mid-to-late twentieth century, due to organochlorine-based contamination, and have subsequently recovered, at least in North American populations. To better understand levels of genetic diversity and population structuring in contemporary populations and to assess the impact of the twentieth century decline, we used genomic data archived in public databases and constructed genomic libraries to isolate and characterize a suite of 17 microsatellite markers for use in merlins. We also conducted cross-amplification experiments to determine the markers' utility in peregrine falcons and gyrfalcons, F. rusticolus. These markers provide a valuable addition to marker suites that can be used to determine individual identity and conduct genetic analyses on merlins and congeners.

Ancient DNA from a 2,500-year-old Caribbean fossil places an extinct bird (Caracara creightoni) in a phylogenetic context.

Since the late Pleistocene humans have caused the extinction of species across our planet. Placing these extinct species in the tree of life with genetic data is essential to understanding the ecological and evolutionary implications of these losses. While ancient DNA (aDNA) techniques have advanced rapidly in recent decades, aDNA from tropical species, especially birds, has been historically difficult to obtain, leaving a gap in our knowledge of the extinction processes that have influenced current distributions and biodiversity. Here we report the recovery of a nearly complete mitochondrial genome from a 2,500 year old (late Holocene) bone of an extinct species of bird, Caracara creightoni, recovered from the anoxic saltwater environment of a blue hole in the Bahamas. Our results suggest that this extinct species is sister (1.6% sequence divergence) to a clade containing the extant C. cheriway and C. plancus. Caracara creightoni shared a common ancestor with these extant species during the Pleistocene (1.2-0.4 MYA) and presumably survived on Cuba when the Bahamas was mostly underwater during Quaternary interglacial intervals (periods of high sea levels). Tropical blue holes have been collecting animals for thousands of years and will continue to improve our understanding of faunal extinctions and distributions. In particular, new aDNA techniques combined with radiocarbon dating from Holocene Bahamian fossils will allow us to place other extinct (species-level loss) and extirpated (population-level loss) vertebrate taxa in improved phylogenetic, evolutionary, biogeographic, and temporal contexts.

The Complete Mitogenome of Falco amurensis (Falconiformes, Falconidae), and a Comparative Analysis of Genus Falco.

In this study, we sequenced the complete mitogenome of Falco amurensis (Falconiformes, Falconidae). The F. amurensis mitogenome is 17,464 bp long, and contains 37 genes, including 13 protein-coding genes (PCGs), two rRNAs, 22 tRNAs, and two non-coding regions (control region and pseudo-control region). Most PCGs initiate with ATG and terminate with TAA. atp8 exhibits the highest evolutionary rate, with cox1 showing the lowest. rrnS and rrnL contain three domains with 46 helices and six domains with 59 helices, respectively. All tRNAs have a typical cloverleaf secondary structure, except that trnS(agy) lacks the dihydrouracil arm. The control region is located between trnT and trnP and the pseudo-control between trnE and trnF. Phylogenetic relationships of 23 species from Falconiformes were analyzed based on the nucleotide sequences of the 13 PCGs and two rRNAs. The results support Falco as a monophyletic taxon, and F. amurensis has a close relationship with the clade containing F. cherrug/F. rusticolus/F. peregrinus.

Description and molecular characterization of a new Leucocytozoon parasite (Haemosporida: Leucocytozoidae), Leucocytozoon californicus sp. nov., found in American kestrels (Falco sparverius sparverius).

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.

Intestinal and liver flukes of birds of prey (Accipitriformes, Falconiformes, Strigiformes) from Slovakia: uniform or diverse compound?

During 2012-2014 up to 286 birds of the orders Falconiformes (5 species), Accipitriformes (11 species), and Strigiformes (7 species) were examined for trematodes and this represents the first detailed study in Slovakia. A total of 12 trematode species belonging to the families Diplostomidae, Cyathocotylidae, Strigeidae, and Opisthorchiidae were identified. Rare infections were found in falcons where only two species (40 %) and three of 85 examined birds (3.5 %) were infected with a low range of two to four worms of generalists Strigea falconis or Plagiorchis elegans. Contrary to that, ten accipitriformes species (90.9 %) and 63 of 156 bird individuals (40.4 %) were infected with nine flukes: Conodiplostomum perlatum, Conodiplostomum spathula, Neodiplostomum attenuatum, Neodiplostomum spathoides, Parastrigea flexilis, Strigea falconis, Strigea vandenbrokae, Paracoenogonimus ovatus, and Metorchis bilis. S. falconis and N. attenuatum were the most frequent, occurring in parallel in eight and four bird species, in numbers up to 575 and 224. The intensity of infection with other fluke species was low ranging from one to 13 worms. Three owl (Strigiformes) representatives (42.9 %) were exclusive hosts for Neodiplostomum canaliculatum and Strigea strigis, and the proportion of positive and dissected individual birds was 10:45 (22.2 %). Both trematodes occurred in two or three owl species. In conclusion, apparent dissimilarity of trematode load of three unrelated lines of falcons, eagles, and owls was revealed. The present study extends our knowledge on the composition of the trematode fauna in Slovakia as all species except S. falconis and P. elegans that represent new host and species records in Slovakia.

Evaluation of the phenol red thread tear test in falconiformes.

Falconiformes are active searchers and hunters that require visual precision to catch their prey and survive in the wild. Despite this, ocular disease is likely to be underdiagnosed in these species, at least in part because of limited proven diagnostic methods and lack of published scientific data. Tear film deficiency is recognized as an important ocular surface disease in dogs but has not been well evaluated in birds. To evaluate the phenol red thread (PRT) tear test as an alternative method to the Schirmer tear test (STT) for determining tear production in Falconiformes, we assessed the PRT tear test twice for each eye in 21 birds from the genus Falco. The mean PRT test values for the right (OD) and left (OS) eyes were OD=30.2±4.6 mm/15 s and OS=29.1±3.7 mm/15 s, with an overall PRT test value for both eyes (OU) of 30.6±4.2 mm/15 s. Good reproducibility was seen with the PRT test as shown by the strong positive correlation between the first and second tests in the birds. The PRT test method provides repeatable results that are easy to obtain, easy to read, and achieved under the same conditions as the STT.

Ticks (Acari: Ixodidae) on resident and migratory wild birds in Orinoquia region, Colombia.

Several species of hard ticks, including those of the genera Ixodes, Haemaphysalis, Amblyomma, and Rhipicephalus, are of medical and veterinary importance and have been reported in association with Neotropical wild birds. Colombia, known for its great bird diversity, has 57 confirmed tick species. However, there are few studies on the association between wild birds and ticks in Colombia. The Orinoquia region, a migratory center in Colombia, provides a unique opportunity to study wild bird-tick associations and their implications for tick-borne disease dynamics. Our study, conducted between October and December 2021, aimed to identify hard ticks infesting resident and migratory wild birds in the department of Arauca and to assess the presence of bacteria from the genera Anaplasma, Borrelia, Ehrlichia, Rickettsia, and piroplasms. A total of 383 birds were examined, of which 21 were infested. We collected 147 ticks, including Amblyomma dissimile (larvae), Amblyomma longirostre (nymphs), Amblyomma mixtum (adults), and Amblyomma nodosum (larvae and nymphs). We did not detect bacterial DNA in the tested ticks; however, piroplasm DNA was detected in ticks from three of the infested birds. Of the 21 bird-tick associations, six are new to the Americas, and interesting documentation of piroplasm DNA in A. longirostre, A. nodosum, and A. dissimile ticks from wild birds in the region. This study provides valuable insights into the ticks associated with wild birds and their role in the dispersal of ticks and pathogens in Colombia, enhancing our understanding of tick life cycles and tick-borne disease dynamics.

The genome sequence of the Mauritius kestrel, Falco punctatus (Temminck, 1821).

We present a genome assembly from an individual male Falco punctatus (the Mauritius kestrel; Chordata; Aves; Falconiformes; Falconidae). The genome sequence is 1,279.3 megabases in span. Most of the assembly is scaffolded into 23 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled and is 17.34 kilobases in length.

Infection of juvenile falcons (Falco spp.) with intestinal Lawsonia intracellularis.

Intestinal infection of many host species with Lawsonia intracellularis are widely reported. Analyses of infections among carnivorous falcons have not previously been reported. Fifty juvenile captive falcons (Falco spp.) with or without Lawsonia infection were investigated in the United Arab Emirates, including clinical laboratory methods. Fresh intestinal biopsy samples were analysed by microbiological techniques for Lawsonia and other bacteria and by standard parasitological and pathological methods. Lawsonia intracellularis infection was diagnosed by microbiological examination and qPCR in 10 of 50 juvenile falcons at case examination. Seven of these 10 falcons were of normal clinical appearance, and the other three had other contributing factors to ill-thrift. A range of other conditions were noted in 40 case control falcons. This first report of Lawsonia infection in falcons suggests that the agent may have a limited contribution to clinical disease in these birds, including ill-thrift syndromes. This lack of clinical disease association mimics that noted among Lawsonia infections recorded in other avian families.

Trophic Niche Breadth of Falconidae Species Predicts Biomic Specialisation but Not Range Size.

Trophic niche breadth plays a key role in biogeographic distribution patterns. Theory posits that generalist strategies are favoured in a more heterogeneous set of environments across a spatio-temporal gradient of resources predictability, conferring individuals and species a greater capacity for colonising new habitats and thus expanding their distribution area. Using the family Falconidae (Aves, Falconiformes) as a model study, we tested the prediction that those species with a wider diet spectrum will have larger geographic range sizes and inhabit more biomes. We assessed the relationships between trophic breadth (diet richness and diversity) at different taxonomic resolutions of the prey (class and order), range size and biomic specialisation index (BSI; number of biomes inhabited) for the different species. Despite different diet breadth indexes and taxonomic resolutions defined differently the trophic niche of the clade and species, our findings revealed that trophic breadth was not a good predictor for range size but was for total environmental heterogeneity, with more diet-generalist species occupying a higher number of biomes. Diet breadth at the order taxonomic level showed a higher capacity of predicting BSI than at class level, and can be an important ecological trait explaining biogeographic patterns of the species.

Detection of Eumonospora henryae (Apicomplexa: Sarcocystidae) from Falco columbarius (Falconiformes: Aves): Comparison of host-parasite phylogram and comments on the family Sarcocystidae Poche, 1913.

The genus Eumonospora Allen, 1933 (Apicomplexa: Sarcocystidae), an avian coccidia, is characterized by monosporocystic and octasporozoic oocysts without Stieda and substieda bodies. Some members of Eumonospora, which infect several raptor species, exhibit high levels of pathogenicity, making eumonosporiosis the leading cause of death in captive-bred raptors. The host specificity of these species appears to be mesostenoxenous, as evidenced by unsuccessful transmission between different orders of avian hosts. However, several studies have detected Eumonospora spp. in taxonomically distant avian hosts, indicating that some of these species may be euryxenous. In the current study, diarrheic fecal examination of a captive-bred juvenile merlin (Falconiformes: Aves) in Tokyo, Japan, was conducted, and a large number of oocysts were morphologically and molecularly identified as E. henryae (Yakimoff and Matschulsky, 1932), a coccidia species reported only in Strigiformes. This is a new recorded host for this coccidia. Phylogenetic analyses via Bayesian inference and maximum likelihood methods using concatenated genomic datasets consisting of nuclear 18S rDNA, nuclear 28S rDNA and mitochondrial cytochrome C oxidase subunit 1 gene, revealed a well-supported monophyletic clade of Eumonospora spp. belonging to the family Sarcocystidae Poche 1913, which largely corresponded to the avian host phylogram. Therefore, based on distinguishable oocyst morphology, a new subfamily, Eumonosporinae, within the family Sarcocystidae, is proposed, and a reconsideration of the definition of Sarcocystidae is suggested. Further molecular characterization of this emerging pathogen, as well as clarification of its complete life cycle, including cyst-forming ability, is required for more appropriate generic assessment.

Peristerophila falcophila sp. nov., a new species and first record of quill mites (Acariformes: Syringophilidae) parasitizing birds of the order Falconiformes.

A new species, Peristerophila falcophila Skoracki and Hromada sp. nov. is described from three avian hosts of the genus Falco: F. peregrinus Tunstall, 1771 from Kenya, Germany and Nepal, F. cherrug Gray, 1834 from Romania, and F. sparverius Linnaeus, 1758 from Colombia. This new species differs from closely related Peristerophila accipitridicus Skoracki et al. 2010 as follow: the propodonotal shield is reduced in the posterior part, but not divided into three separate shield (vs. divided into three punctate and saber-like sclerites in P. accipitridicus); the length ratio of setae ve:si is 1:1.6-1.8 (vs. 1:2-2.8); fan-like setae p' and p" of legs III and IV are with 10 tines (vs. 19-20); and the length of setae e2 is 145-155 (vs. 185-215). Additionally, the key to all species of the genus Peristerophila is constructed and the host-parasite relationships are briefly discussed.

Central European Strigeidae Railliet, 1919 (Trematoda: Strigeidida): Molecular and comparative morphological analysis suggests the reclassification of Parastrigea robusta Szidat, 1928 into Strigea Abildgaard, 1790.

Strigeidae Railliet, 1919 are digenean parasites of birds and mammals that are characteristic by their cup-shaped forebody and bilobed holdfast organ. Despite that the family is taxonomically unsettled, particularly due to a very limited number of visible autapomorphic identification features, molecular phylogenetics have never been applied to analyze the relationships among European members of Strigeidae except for the genus Ichthyocotylurus. Here, we analyze the Strigeidae found during the examination of Czech birds performed from 1962 to 2017, and we provide comparative measurements and host spectra, including prevalence and intensity; we also provide and analyze sequences of four DNA loci of 12 of the Strigeidae species. We suggest the reclassification of Parastrigea robusta Szidat, 1928 as Strigea robusta (Szidat, 1928) Heneberg and Sitko, 2018 comb. n. The genera Strigea Abildgaard, 1790 and Parastrigea Szidat, 1928 appear paraphyletic, and morphological diagnostic features of genera within Strigeini Dubois, 1936 are invalid. The mute swan Cygnus olor hosts two Cotylurus spp., Cotylurus syrius Dubois, 1934 and a second species with molecular identification features shared in part with Cotylurus cornutus (Rudolphi, 1808) and Cotylurus gallinulae Lutz, 1928. New host records are provided for seven species. Analyses of non-European genera of the Strigeidae are needed to provide an updated key to Strigeini.

Histological and histochemical study of the uropygial gland of chimango caracara (Milvago chimango vieillot, 1816).

The uropygial glands of birds are sebaceous organs that contribute to the water-repellent properties of the feather coat. We studied the histological and histochemical characteristics of the uropygial gland of chimango caracara using hematoxylin and eosin (H & E), Gomori´s trichrome, orcein, Gomori´s reticulin, periodic acid-Schiff (PAS), Alcian blue (AB) and a variety of lectins. The gland is composed of two lobes and a papilla with 20 downy feathers. It is surrounded by a capsule of dense connective tissue that contains elastic, reticular and smooth muscle fibers. The papilla is delicate and has two excretory ducts. The gland mass relative to body mass was 0.143%. Both adenomer cells and their secretions were stained with Sudan IV, PAS and AB, and were positive for numerous lectins that indicated the presence of lipids and carbohydrates. Immunohistochemical techniques to detect PCNA confirmed cell proliferation in the basal stratum of the adenomer cells. The lipids and glycoconjugates secreted by the uropygial gland serve numerous functions including protection against microorganisms.

Caryospora neofalconis and other enteroparasites in raptors from Mexico.

A coprological survey of enteroparasites in raptors (60 Falconiformes) from Central Mexico is reported. Three samples contained coccidian unsporulated oocysts, one contained Eimeria sp., one contained trematode eggs and one contained capillarid and trematode eggs and Eimeria sp. After sporulation at the laboratory, oocysts from a Falco peregrinus were identified as Caryospora neofalconis. The phylogenetic analysis of the C. neofalconis (GenBank accession number KT037081) showed a close relationship to the Australian strain RY 2014 isolate 16710 (GenBank accession number KJ634019) of Caryospora daceloe, with 99.2% similarity. As far as we are aware, this is the first report of C. neofalconis in raptors from Mexico and the Americas.

Prognostic indicators associated with early mortality of wild raptors admitted to a wildlife rehabilitation centre in Spain.

BACKGROUND: Assessment of the prognostic indicators of wildlife casualties is critical in wildlife rehabilitation practice, to optimize the use of economical resources, and to protect animal welfare. Few studies have been conducted in this field. OBJECTIVE: To identify the prognostic indicators associated with raptor mortality during the first week of hospitalization. ANIMALS AND METHODS: Complete medical records of 1722 wild raptor cases admitted to a wildlife rehabilitation centre from 1995 to 2007 were used. Regression models were created to determine mortality-related factors for different variables (order, sex, body condition (BC), clinical signs, and available haematological and biochemical parameters). RESULTS: In the bivariate analysis, the presence of nervous (OR = 11.9, 95%CI:5.1-27.6) or musculoskeletal (OR = 12.1, 95%CI:5.8-25.3) signs, a poor BC (OR = 32.9, 95%CI:19-81.2), and low values of packed cell volume (PCV), haemoglobin or total solids (TS), were all associated with early mortality. After adjusting variables in the multivariate model, BC was excluded due to co-linearity with other variables, and alteration of the nervous system was the only significant risk factor (OR = 4.0; 95%CI:1.9-8.8). In species specific analysis, poor prognosis was related to neurological signs in Athene noctua, poor BC in Strix aluco, trauma in Acciptiter nisus and Tyto alba, low PCV in Buteo buteo and Falco tinnunculus and low TS in Falco tinnunculus. CONCLUSIONS: Raptors with a poor BC, low values of PCV and those presenting with neurological signs, had the highest risk of dying in the first days of admittance. Thus, either medical care or humane euthanasia for poor prognosis should be performed to address animal welfare.

Miscellaneous ecological notes on Brazilian birds of prey and owls / Notas ecológicas variadas sobre aves de rapina e corujas brasileiras

Sixteen opportunistic field observations of eight species of Brazilian raptors (Falconiformes and Strigiformes) are reported here as a contribution to the knowledge of the natural history of these poorly studied birds in Brazil. The observations are related to the food habits (Buteo albicaudatus, Herpetotheres cachinnans, Milvago chimachima, Falco femoralis), reproduction (Asio stygius, Megascops choliba), mobbing behaviour elicited in other birds (Geranospiza caerulescens, H. cachinnans, F. femoralis, A. stygius, Athene cunicularia) and a rare case of leucism in owls (A. cunicularia).

Dezesseis observações de campo oportunísticas, envolvendo oito espécies de aves de rapina brasileiras (Falconiformes e Strigiformes) são aqui relatadas como uma contribuição para o conhecimento da história natural dessas aves relativamente pouco estudadas em nosso país. As observações estão relacionadas aos hábitos alimentares (Buteo albicaudatus, Herpetotheres cachinnans, Milvago chimachima, Falco femoralis), reprodução (Asio stygius, Megascops choliba), comportamento de tumulto provocado em outras aves (Geranospiza caerulescens, H. cachinnans, F. femoralis, A. stygius, Athene cunicularia) e um caso raro de leucismo em corujas (A. cunicularia).