Campylobacter jejuni infection associated with relatively poor condition and low survival in a wild bird

Campylobacter jejuni is the most common foodborne pathogen in industrialized countries. Most human infections come from contaminated poultry, but wild birds are also known to harbor C. jejuni. Wild birds are often described as asymptomatic carriers, but this assumption is based on domestic poultry research. We studied the effects of C. jejuni infection on body condition and survival of adult and nestling American crows Corvus brachyrhynchos in Davis, California. Previous work demonstrated that more than half of the crows in this population are infected with C. jejuni and that at least some of the isolates carried by crows are similar to those found in domestic animals and humans. In this study, we compared the body condition of infected and uninfected individuals at the time of capture among adults (n = 44; 52% infected) and nestlings (n = 97; 77% infected). We subsequently monitored these banded individuals for up to 3 yr and used mark–recapture survival analysis to estimate relationships between infection status and later survival. We found that adult crows infected with C. jejuni were in poor condition relative to uninfected adults: average body mass of infected birds was 12% lower, whereas average body size did not differ between the two groups. Likewise, apparent survival probability was lower for infected adults. In contrast, nestling body condition, fledging success, and survival did not differ by infection status. This is the first study to document adverse effects of C. jejuni infection in a free‐living, wild bird. If these effects are widespread, C. jejuni exposure may be a cause of conservation concern for some species, especially when human activities increase exposure to infections or introduce novel strains to wild bird populations. Our results add to the growing body of work demonstrating hidden long‐term costs of seemingly mild infections in wild populations.     

Sources of variation in haematocrit in birds

The validity of the haematocrit or packed cell volume as an indicator of condition in wild birds has recently been questioned. We reviewed over 300 published papers on haematocrit values for wild birds. These studies show that changes in haematocrit could be caused by a number of different natural factors that include age, sex, geographical elevation, energy expenditure, parasitism, nutrition and genetics. Haematocrit also increased with age from hatching, due to increased erythropoiesis, so that adult birds generally have greater haematocrit values than nestlings or juveniles. Haematocrit values were either independent of elevation or increased with elevation. A meta-analysis of 36 studies showed no difference in haematocrit between the sexes. Relationships between haematocrit value and both energy expenditure and parasitic infection vary between studies. In temperate climates, haematocrit tended to be higher in winter than in summer, which may be due to dehydration or increased oxygen demand caused by thermogenesis, moult or acquisition of reproductive status. Our review indicates that the use of haematocrit as a sole indicator of condition or health could lead to incorrect conclusions if natural factors that can affect haematocrit are not taken into consideration.     

Haematocrit is weakly related to condition in nestling Barn Swallows Hirundo rustica

Currently, there is no agreement about the suitability of haematocrit (the proportion of blood volume occupied by packed red blood cells) as a predictor of condition in birds. In order to clarify this point, genetic and environmental components of phenotypic variation for a number of traits were estimated in nestling Barn Swallows Hirundo rustica by means of a partial cross-fostering experiment. The studied traits were haematocrit, two morphological traits used as estimates of condition in birds (body mass and body mass relative to body size) and a morphological trait that presumably is not associated with condition (tarsus length). First, we found that body mass relative to body size was related to haematocrit, supporting the suggestion that haematocrit reflects condition in this species. Secondly, we found that the coefficient of residual (i.e. environmental) variation of haematocrit was larger than that of tarsus length, but smaller than those of body mass or body mass relative to body size. Under the hypothesis that traits closely related to condition (and, ultimately, to fitness) are characterized by large residual variance, these results also suggest that haematocrit is related to condition, but that this relationship must be weak. Therefore, the use of haematocrit as an estimate of condition is not recommended. Finally, heritabilities of the studied traits were calculated, differing significantly from zero only for tarsus length, the trait with the smallest residual variation. However, a consistent pattern in the relationship between heritability and genetic variation was not found.     

Ageing and reproduction: antioxidant supplementation alleviates telomere loss in wild birds

Reproduction is inherently costly. Environmental stressors, such as infection and limited food resources, can compromise investment at each breeding attempt. For example, recent data on captive birds showed that increased reproductive effort accelerates ageing. However, the effects of nutritional status and infection on ageing remain unknown. Telomeres function as protective caps at the ends of eukaryotic chromosomes, and changes in telomere length is a commonly used proxy for ageing. To partially address the mechanisms of ageing following reproduction, we supplemented, medicated or administered a combined treatment to wild blue tits (Cyanistes caeruleus) breeding in central Spain during 2012. The nutritional supplement consisted of two different antioxidants, whereas the medication was an antimalarial treatment against blood parasites. We evaluated the effect of these manipulations on reproductive success and parasite loads in the first breeding season, and on changes in telomere length between two consecutive breeding seasons. Supplemented birds showed no reduction in blood parasite infections in 2012, although they exhibited higher body mass and fledging success. The antimalarial drugs reduced infections by several parasite species, but this had no effect on fitness parameters. In the following season, telomeres from supplemented birds had shortened less. Altogether, we found that supplementation with antioxidants provided fitness benefits in the short term and reduced telomere loss a year following treatment. Our results provide indirect empirical support for accelerated telomere loss as a cost of reproduction.     

Co‐infections by malaria parasites decrease feather growth but not feather quality in house martin

During moult, stressors such as malaria and related haemosporidian parasites (e.g. Plasmodium and Haemoproteus) could affect the growth rate and quality of feathers, which in turn may compromise future reproduction and survival. Recent advances in molecular methods to study parasites have revealed that co‐infections with multiple parasites are frequent in bird–malaria parasite systems. However, there is no study of the consequences of co‐infections on the moult of birds. In house martins Delichon urbica captured and studied at a breeding site in Europe during 11 yr, we measured the quality and the growth rate of tail feathers moulted in the African winter quarters in parallel with the infection status of blood parasites that are also transmitted on the wintering ground. Here we tested if the infection with two haemosporidian parasite lineages has more negative effects than a single lineage infection. We found that birds with haemosporidian infection had lower body condition. We also found that birds co‐infected with two haemosporidian lineages had the lowest inferred growth rate of their tail feathers as compared with uninfected and single infected individuals, but co‐infections had no effect on feather quality. In addition, feather quality was negatively correlated with feather growth rate, suggesting that these two traits are traded‐off against each other. We encourage the study of haemosporidian parasite infection as potential mechanism driving this trade‐off in wild populations of birds.     

Response of the haematocrit to body condition changes in Northern Bald Ibis Geronticus eremita

We study the usefulness of the haematocrit as a predictor of body condition in birds, using a captive population of the endangered species Northern Bald Ibis (Geronticus eremita). This population is 14% of the worldwide captive population, which is far greater than the known free-living population. The haematocrit, body mass and body condition index responded in the same sense to two different nutritional periods, and there was a statistically significant relationship between changes in condition index and haematocrit of individual birds between the two periods. We discuss the relationship of these parameters with subcutaneous fat and muscle mass, and analyse the individuals' nutritional status in each of the periods studied. The conclusion was that the haematocrit is sensitive to variations in body condition since it responds to mass-loss processes corresponding to phases of mobilization of fat reserves, a situation prior to the mobilization of muscle proteins when there is a manifest deterioration of the individual's aspect.     

Minor differences in body condition and immune status between avian influenza virus-infected and noninfected mallards: a sign of coevolution?

Wildlife pathogens can alter host fitness. Low pathogenic avian influenza virus (LPAIV) infection is thought to have negligible impacts on wild birds; however, effects of infection in free‐living birds are largely unstudied. We investigated the extent to which LPAIV infection and shedding were associated with body condition and immune status in free‐living mallards (Anas platyrhynchos), a partially migratory key LPAIV host species. We sampled mallards throughout the species' annual autumn LPAIV infection peak, and we classified individuals according to age, sex, and migratory strategy (based on stable hydrogen isotope analysis) when analyzing data on body mass and five indices of immune status. Body mass was similar for LPAIV‐infected and noninfected birds. The degree of virus shedding from the cloaca and oropharynx was not associated with body mass. LPAIV infection and shedding were not associated with natural antibody (NAbs) and complement titers (first lines of defense against infections), concentrations of the acute phase protein haptoglobin (Hp), ratios of heterophils to lymphocytes (H:L ratio), and avian influenza virus (AIV)‐specific antibody concentrations. NAbs titers were higher in LPAIV‐infected males and local (i.e., short distance) migrants than in infected females and distant (i.e., long distance) migrants. Hp concentrations were higher in LPAIV‐infected juveniles and females compared to infected adults and males. NAbs, complement, and Hp levels were lower in LPAIV‐infected mallards in early autumn. Our study demonstrates weak associations between infection with and shedding of LPAIV and the body condition and immune status of free‐living mallards. These results may support the role of mallards as asymptomatic carriers of LPAIV and raise questions about possible coevolution between virus and host.     

MHC‐I provides both quantitative resistance and susceptibility to blood parasites in blue tits in the wild

Major histocompatibility complex (MHC) genes are central for the adaptive immune response against parasites. Here, we investigated potential associations among MHC‐I alleles and blood parasite infections in a natural breeding population of a passerine bird, the blue tit Cyanistes caeruleus, in central Spain. We screened both infection status (presence/absence of infection) and infection intensity to the pathogenic blood parasites Haemoproteus and Leucocytozoon. Three MHC‐I alleles (UA104, UA108 and UA117) were associated with higher or lower infection intensities by Leucocytozoon. Interestingly, these associations were dependent on age and were found both among young and adult birds. No MHC alleles were associated with infection intensity by Haemoproteus parasites. In addition, no significant relationships were detected between infection status by Haemoproteus and Leucocytozoon infections and MHC alleles. The very high prevalence of these two parasites in our study population (79–100%) poses challenges to identify associations with infection status and also suggests that clearance of infections may be rare. In conclusion, associations between specific MHC‐I alleles and Leucocytozoon parasites were related to either high or low infection intensities, and hence increased susceptibility or resistance to infection.     

Malarial parasites decrease reproductive success: an experimental study in a passerine bird

Malarial parasites are supposed to have strong negative fitness consequences for their hosts, but relatively little evidence supports this claim due to the difficulty of experimentally testing this. We experimentally reduced levels of infection with the blood parasite Haemoproteus prognei in its host the house martin Delichon urbica, by randomly treating adults with primaquine or a control treatment. Treated birds had significantly fewer parasites than controls. The primaquine treatment increased clutch size by 18%; hatching was 39% higher and fledging 42% higher. There were no effects of treatment on quality of offspring, measured in terms of tarsus length, body mass, haematocrit or T-cell-mediated immune response. These findings demonstrate that malarial parasites can have dramatic effects on clutch size and other demographic variables, potentially influencing the evolution of clutch size, but also the population dynamics of heavily infected populations of birds.     

Effect of endurance flight on haematocrit in migrating birds

The effects of an endurance flight on the haematocrit, the percentage of packed red blood cells per blood volume, were examined within the framework of six possible factors explaining possible changes in the haematocrit. Two approaches were adopted: (1) the haematocrit was studied in four species of passerine birds which landed on an Italian island after having crossed the Mediterranean Sea on their spring migration in a non-stop flight; (2) the haematocrit was evaluated in six individual red knots after a flight of 1, 2, 4 and 10 h in a wind tunnel and the data thus obtained compared with data on resting birds with or without food. In the four passerine species, the haematocrit decreased from 51% in fat birds to 48% in lean birds. In lean birds, the haematocrit dropped from 48% in birds with well-developed breast muscles to 36% in birds with emaciated breast muscles. In the red knots, the haematocrit was dependent on body mass in flying and resting birds. The haematocrit decreased from about 51% pre-flight to about 49% within 1 h of flight and remained at this level for up to 10 h of flight. Taking the results from the passerines and the red knots together, it seems that the haematocrit drops by a few percentage points within 1 h after the onset of flight, decreases very slowly with decreasing body mass and decreases more steeply in very lean birds having entered stage III of fasting. This indicates that dehydration is not an underlying factor in decreased haematocrit because if this were the case we would expect an increase with endurance flight. We found no effect of the presence of blood parasites on haematocrit. With the onset of flight, haemodilution may be adaptive, because it reduces blood viscosity and, thereby, energy expenditure by the heart, or it may be a sign of water conservation as an insurance against the risk of dehydration during long non-stop flights. During endurance flight, a reduction in the haematocrit may be adaptive, in that oxygen delivery capacity is adjusted to the decreased oxygen needs as body mass decreases. A decreasing haematocrit would also allow birds to reduce heart beat frequency and/or heart size, because blood viscosity decreases disproportionally with decreasing haematocrit. However, when energy stores are about to come to an end and birds increase protein breakdown, the haematocrit decreases even further, and birds probably become anaemic due to a reduced erythropoiesis.     

Sex-biased,but not plumage color-based,prevalence of haemosporidian parasites in free-range chickens

Previous studies found a relationship between blood parasite infection and bird gender, with higher prevalence in males. Some studies also found a relationship between host plumage color and parasitic infection, while others did not. Here, we investigated the blood parasite prevalence in correlation with sex and plumage color in free-range chickens (Gallus gallus domesticus) in China. We analyzed a total of 297 blood samples, out of which 234 chickens tested positive for haemosporidian parasites, with 78.5% parasite prevalence. Out of 139 males, 118 tested positive with 84.8% parasite prevalence while 116 of 158 female samples tested positive (73.4%). Leucocytotozoon was the most frequent genus isolated (193 infected individuals /234 birds), followed by Plasmodium (41 infected individuals/234 birds), with no Haemoproteus parasites being detected. There were no significant differences in the body parameters and chicken color plumages with regards to the infection status. Our study indicated that blood parasite infection was significantly different between male and female chickens, with infection prevalent in males.     

Pathophysiological responses to a schistosome infection in a wild population of mourning doves (Zenaida macroura)

The blood trematode Gigantobilharzia huronensis typically infects passerine birds and has not been reported in other orders of wild birds. However, in the summer of 2011 in Tempe, Arizona, USA, mourning doves (Zenaida macroura; order: Columbiformes) were collected with infections of G. huronensis. This is the first report of a natural schistosome infection found in wild populations of doves. We sought to determine if G. huronensis infections alter the general body condition and physiology of doves, a seemingly unlikely host for this parasite. Specifically, we hypothesized that birds infected with schistosomes would exhibit reduced weight as well as increased markers of stress and immune system activation. Adult male mourning doves (n = 14) were captured using walk-in style funnel traps. After weighing the birds, blood and mesenteric tissue samples were collected. We measured biomarkers of stress including circulating heat shock proteins (HSPs) 60 and 70, as well as oxidized lipoproteins in schistosome-infected and non-infected birds. Indices of immune system reactivity were assessed using agglutination and lysis assays in addition to determining the leukocyte to erythrocyte ratios and prevalence of hemoparasite infections from blood smears. Schistosome-infected mourning doves had significantly increased oxidative stress and evidence of HSP70 mobilization. There was no evidence for weight loss in schistosome-infected birds nor evidence of significant immune system activation associated with schistosome infection. This may be a reflection of the small sample size available for the study. These findings suggest that schistosome infections have pathological effects in doves, but the lack of mature worms suggests that infected birds in this sampling may not have been suitable hosts for parasite maturation.     

Haematological parameters do senesce in the wild: evidence from different populations of a long‐lived mammal

Increasing evidence of senescence has been reported from long‐term studies of wild populations. However, most studies have focused on life‐history traits like survival, reproduction or body mass, generally from a single intensively monitored population. However, variation in the intensity of senescence across populations, and to a lesser extent between sexes, is still poorly understood. In addition, the pattern of age‐specific changes in haematological parameters remains virtually unknown to date for any population of vertebrate living in the wild. Using repeated blood samples collected from known‐aged (2–15 years of age) roe deer (Capreolus capreolus) from two populations facing highly different environmental conditions, we filled the gap. In particular, we investigated age‐specific changes in haematocrit, albumin and creatinine. We reported clear evidence of senescence in all haematological parameters. Moreover, senescence patterns differed between sexes and populations. The rate of senescence was higher in males than in females for haematocrit with no site difference. On the other hand, the rate of senescence in creatinine was higher at Trois Fontaines than at Chizé with no sex difference. Our findings provide a first demonstration of age‐specific declines in haematological parameters in wild populations of large herbivores and show that the process of senescence in vertebrates is not restricted to body mass or fitness components. We also demonstrate that the senescence pattern of haematological parameters is context dependent and varies both between sexes and according to environmental conditions.     

Effect of repeated exposure to Plasmodium relictum (lineage SGS1) on infection dynamics in domestic canaries

Parasites are known to exert strong selection pressures on their hosts and, as such, favour the evolution of defence mechanisms. The negative impact of parasites on their host can have substantial consequences in terms of population persistence and the epidemiology of the infection. In natural populations, however, it is difficult to assess the cost of infection while controlling for other potentially confounding factors. For instance, individuals are repeatedly exposed to a variety of parasite strains, some of which can elicit immunological memory, further protecting the host from subsequent infections. Cost of infection is, therefore, expected to be particularly strong for primary infections and to decrease for individuals surviving the first infectious episode that are re-exposed to the pathogen. We tested this hypothesis experimentally using avian malaria parasites (Plasmodium relictum-lineage SGS1) and domestic canaries (Serinus canaria) as a model. Hosts were infected with a controlled dose of P. relictum as a primary infection and control birds were injected with non-infected blood. The changes in haematocrit and body mass were monitored during a 20 day period. A protein of the acute phase response (haptoglobin) was assessed as a marker of the inflammatory response mounted in response to the infection. Parasite intensity was also monitored. Surviving birds were then re-infected 37 days post primary infection. In agreement with the predictions, we found that primary infected birds paid a substantially higher cost in terms of infection-induced reduction in haematocrit compared with re-exposed birds. After the secondary infection, re-exposed hosts were also able to clear the infection at a faster rate than after the primary infection. These results have potential consequences for the epidemiology of avian malaria, since birds re-exposed to the pathogen can maintain parasitemia with low fitness costs, allowing the persistence of the pathogen within the host population.     

Plasmodium relictum (lineage P-SGS1): effects on experimentally infected passerine birds

We evaluated the effects of Plasmodium relictum (lineage P-SGS1), which is a host generalist, to five species of passerine birds. Light infection of P. relictum was isolated from a naturally infected adult reed warbler Acrocephalus scirpaceus. The parasites were inoculated to naive juveniles of the chaffinch Fringilla coelebs, common crossbill Loxia curvirostra, house sparrow Passer domesticus, siskin Spinus spinus and starling Sturnus vulgaris. Susceptibility of these birds to the infection of P. relictum was markedly different. This parasite developed in birds belonging to the Fringillidae and Passeridae but the starlings (Sturnidae) were resistant. Only 50% of experimental house sparrows were susceptible to the infection. The intensity of parasitemia varied markedly inside and between different susceptible bird species. There were no effects of the infection on body mass or temperature of experimentally infected birds. Infection of P. relictum leads to the significant decrease of haematocrit value and hypertrophy of spleen and liver in heavily infected common crossbills and siskins. This study shows that infection of the same lineage of P. relictum causes diseases of different severity in different avian hosts; that might have different evolutionary consequences and should be taken in consideration in conservation projects.     

A non‐lethal biopsy technique for sampling subcutaneous adipose tissue of small and medium‐sized birds

Analysis of fatty acids from adipose tissue can provide important information about the physiological and nutritional condition of birds. However, non‐lethal biopsy procedures and their potential negative effects on small and medium‐sized birds have not been adequately assessed. We developed a biopsy procedure for collecting small amounts of adipose tissue from the furcular area of small and medium‐sized birds (13–62 g) without adverse effects. The biopsy procedure was performed on Dunlins (Calidris alpina), a medium‐sized migratory shorebird, and small hybrid songbirds (European Goldfinch [Carduelis carduelis] × Atlantic Canary [Serinus canaria]). The biopsy involved making a skin incision 2–3 mm long on one side of the furcular region to collect 2–16 mg of adipose tissue. All birds were monitored for 2 weeks after biopsies to examine potential effects of the procedure on body mass, visible fat deposition, time for wound healing, hematocrit levels, total white blood cell counts, and heterophil:lymphocyte ratios. Visible scars were apparent for 10 d for hybrids and 6 d for Dunlins, with no evidence of infection or abnormal scar tissue formation. Body mass of songbirds did not differ before and after the biopsy, but Dunlins increased body mass and visible fat deposition after biopsy. The collection of adipose tissue in the furcular region was performed only for birds with fat scores ≥2, and the tissue collected never represented more than 0.07% of a bird's body mass; we recommend both these values to avoid any possible unknown negative effects. Our non‐lethal biopsy technique is relatively simple to perform, and we recommend it as an alternative to lethal methods for sampling adipose tissue in studies of wild and captive birds.     

Effects of carotenoids, immune activation and immune suppression on the intensity of chronic coccidiosis in greenfinches

Allocation trade-offs of carotenoids between their use in the immune system and production of integumentary colouration have been suggested as a proximate mechanism maintaining honesty of signal traits. We tested how dietary carotenoid supplementation, immune activation and immune suppression affect intensity of coccidian infection in captive greenfinches Carduelis chloris, a passerine with carotenoid-based plumage. Immune activation with phytohaemagglutinin (PHA) decreased body mass among birds not supplemented with lutein, while among the carotenoid-fed birds, PHA had no effect on mass dynamics. Immune suppression with dexamethasone (DEX) induced loss of body mass and reduced the swelling response to PHA. DEX and PHA increased the concentration of circulating heterophils. Lutein supplementation increased plasma carotenoid levels but had no effect on the swelling response induced by PHA. PHA and DEX treatments did not affect plasma carotenoids. Immune stimulation by PHA suppressed the infection, but only among carotenoid-supplemented birds. Priming of the immune system can thus aid in suppressing chronic infection but only when sufficient amount of carotenoids is available. Our experiment shows the importance of carotenoids in immune response, but also the complicated nature of this impact, which could be the reason for inconsistent results in studies investigating the immunomodulatory effects of carotenoids. The findings about involvement of carotenoids in modulation of an immune response against coccidiosis suggest that carotenoid-based ornaments may honestly signal individuals’ ability to manage chronic infections.     

Migration distance does not predict blood parasitism in a migratory songbird

Migration can influence host–parasite dynamics in animals by increasing exposure to parasites, by reducing the energy available for immune defense, or by culling of infected individuals. These mechanisms have been demonstrated in several comparative analyses; however, few studies have investigated whether conspecific variation in migration distance may also be related to infection risk. Here, we ask whether autumn migration distance, inferred from stable hydrogen isotope analysis of summer‐grown feathers (δ²H_f) in Europe, correlates with blood parasite prevalence and intensity of infection for willow warblers (Phylloscopus trochilus) wintering in Zambia. We also investigated whether infection was correlated with individual condition (assessed via corticosterone, scaled mass index, and feather quality). We found that 43% of birds were infected with Haemoproteus palloris (lineage WW1). Using generalized linear models, we found no relationship between migration distance and either Haemoproteus infection prevalence or intensity. There was spatial variation in breeding ground origins of infected versus noninfected birds, with infected birds originating from more northern sites than noninfected birds, but this difference translated into only slightly longer estimated migration distances (~214 km) for infected birds. We found no relationship between body condition indices and Haemoproteus infection prevalence or intensity. Our results do not support any of the proposed mechanisms for migration effects on host–parasite dynamics and cautiously suggest that other factors may be more important for determining individual susceptibility to disease in migratory bird species.     

Plasmodium relictum (lineage SGS1) and Plasmodium ashfordi (lineage GRW2): the effects of the co-infection on experimentally infected passerine birds

The effects of avian malaria parasites of the genus Plasmodium on their hosts are insufficiently understood. This is particularly true for malarial co-infections, which predominant in many bird populations. We investigated effects of primary co-infection of Plasmodium relictum (lineage SGS1) and Plasmodium ashfordi (GRW2) on experimentally infected naive juveniles of siskin Spinus spinus, crossbill Loxia curvirostra and starling Sturnus vulgaris. All siskins and crossbills were susceptible but starlings resistant to both these infections. A general pattern of the co-infections was that heavy parasitemia (over 35% during peaks) of both parasites developed in both susceptible host species. There were no significant effects of the co-infections on mean body mass of the majority of infected birds. Mean haematocrit value decreased approximately 1.5 and 3 times in siskins and crossbills at the peak of parasitemia, respectively. Mortality was recorded among infected crossbills. We conclude that co-infections of P. relictum and P. ashfordi are highly virulent and act synergetically during primary infections in some but not all passerine birds.     

Ticks Parasitizing Wild Birds in Portugal: Detection of Rickettsia aeschlimannii, R. helvetica and R. massiliae

From January 2002 to December 2004, 152 ticks were collected from 40 wild birds recovered in Santo André Natural Reserve and Monsanto Forestal Park, Portugal mainland. Five ticks species were identified from 22 species of birds, and new host record were provided for some species. In addition, 32 (21%) ticks were screened by PCR to detect infections with agents belonging to order Rickettsiales: Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Rickettsia spp. PCR amplicons were obtained in 5 (15.6%) tick samples. Rickettsia DNA exhibiting gltA sequences similar to those of Rickettsia aeschilimannii, R. helvetica and R. massiliae were identified in Hyalomma marginatum, Ixodes ventalloi and in Rhipicephalus turanicus, respectively. This is the first report of rickettsiae infections in ticks collected from wild birds in Portugal. Giving the results presented above wild birds play an important role in the maintenance and dissemination of several tick species and associated rickettsiae.