Cytochrome P450 enzyme activity in five herbivorous,non-passerine bird species

We examined hepatic cytochrome P450 activity in wild and hand-reared grey partridges (Perdix perdix), capercaillies (Tetrao urogallus) and ring-necked pheasants (Phasianus colchicus), as well as the enzyme activity in a variety of tissues of hand-reared Japanese quails (Coturnix coturnix japonica) and pigeons (Columba livia). Post-mortem decrease in hepatic enzyme activity in the grey partridge was measured. Hepatic 7-ethoxyresorufin-O-deethylase activity was similar in wild and hand-reared grey partridges and pheasants, but the activity was significantly lower in wild than in hand-reared capercaillies, probably resulting from their phenolic-rich diet. In the tissues of both quails and pigeons 7-ethoxycoumarin-O-deethylase exhibited the highest and 7-pentoxyresorufin-O-deethylase the lowest activity. Hepatic enzyme activity was significantly higher than that in other tissues. In the small intestine some activity could be found, reflecting some intestinal detoxication capacity. Enzyme activity decreased by 34-69% during the 30-min sampling period, which confirmed the importance of equalising sampling time to obtain comparable data. Because the hand-reared birds in this study were fed the same commercial diets, we assumed that the enzyme activity values detected reflect species differences without any induction by dietary secondary compounds.     

Why do many pheasants released in the UK die,and how can we best reduce their natural mortality?

Around 60% of pheasants released for shooting in the UK, an estimated 21 million birds, do not end up at their intended fate: being shot. This constitutes wastage, raising economic, environmental and ethical questions. We review what is known of the fates of released pheasants and consider why they do not directly contribute to the numbers harvested. We focus on four main explanations: predation, disease, starvation and dispersal, and highlight other important causes of mortality. For each explanation, we attempt to attribute levels of loss and identify timings or conditions when such losses may be heaviest. We review factors that exacerbate losses and methods available to mitigate them. Opportunities for amelioration may arise at all stages of the rearing and release of pheasants and involve changes to the conditions under which eggs are produced, the way young pheasants are reared or the management of the environment into which they are released. We found few studies investigating impacts of post-release management techniques on pheasant survival outside of the breeding season within a UK context. We found that a number of less commonly deployed practices focusing on early-life, pre-release management may improve survival. Given the scale of pheasant releasing in the UK, even improvements in survival of 1% would mean that ~?350,000 fewer birds die of natural causes. Complementing current post-release management with proven novel pre-release management interventions could reduce the number of pheasants required for release, whilst maintaining current shooting levels. Lowering release numbers would lower financial costs, benefit the environment and reduce some ethical concerns over the release and shooting of reared pheasants.     

The effects of released pheasants on invertebrate populations in and around woodland release sites

The release of gamebirds for recreational shooting exerts a series of effects on the ecosystems into which they are placed. Pheasants (Phasianus colchicus) are omnivorous and eat invertebrates, especially when young or, if females, when breeding. Consequently, the release of large numbers of pheasants into woodland release pens may affect local invertebrate populations. Previous studies have reported mixed evidence. We conducted pitfall trapping at 13 sites (49 pens) in central England over 2 years (totaling 65 pen measures), comprising three surveys annually, immediately prior to releases in mid‐summer, 4 weeks later when most birds were still in the pens, and another 5 weeks later when most birds had dispersed. We compared traps inside and 25 m outside pens in the same wood. We considered release densities and whether the birds had prior experience of eating invertebrates. While accounting for overall seasonal declines in invertebrates trapped, we detected changes for total invertebrate biomass and total counts indicative of released pheasants causing local decreases inside pens, either directly by predation or indirectly by modifying vegetation. There were also relative decreases outside pens when the pheasants start to disperse, suggesting that the released pheasants may be affecting invertebrates in those nearby areas or that their earlier effects inside the pen, modifying vegetation or increasing invertebrate activity, increased the relative susceptibility of invertebrates there to trapping. However, these effects were not seen for specific invertebrate groups believed to be especially susceptible to pheasants. For slugs and detritivores, we detected small population increases inside pens. Across the study period, decreases for most measures were greater outside pens than inside them. We conclude that any effects pheasants have on invertebrate communities at release sites in woodlands are complex and that long‐term and taxon‐specific studies should be considered to understand the local net ecological effects of gamebird releases on invertebrates.     

Post-release survival of oiled, cleaned seabirds in North America

The number of days between ringing and recovery of oiled, cleaned and released seabirds was extremely low, usually a matter of a few days or weeks, and for three species was 5–100 times lower than for non-oiled birds. For oiled, cleaned Guillemots Una aalge , postrelease life expectancy was 9.6 days and long-term recovery rates were 10–20% of those of non-oiled birds. Measures of survival were not greater for oiled birds treated in recent years with modern methods. The cost and effectiveness of rehabilitation efforts for oiled seabirds need to be reexamined in the light of results showing low post-release survival.     

Do helminths increase the vulnerability of released pheasants to fox predation?

The success of ring-necked pheasant (Phasianus colchicus) restocking in Asturias, northern Spain was assessed, and the role of parasites and predators in the mortality of released birds was studied. The experimental release of 56 radio-tagged pheasants showed that 98% of birds died within 12 days. As soon as 72 h after release, 67.5% of males and 55.0% of females were found dead. Foxes (Vulpes vulpes) killed 63% of the birds. The survival of those birds killed by foxes was lower than for birds which died due to other causes, and pheasants depositing eggs of the nematode Eucoleus contortus (Creplin, 1839) survived less than those apparently non-parasitized. No impact of the parasite on the pheasants' condition was found, but foxes preyed upon parasitized birds more than expected by random. The results suggest that: (i) the current pheasant releases in this area are unsuccessful and need to be improved; (ii) this is mainly due to intense predation by red foxes; and (iii) parasites could have some influence on the predation of released birds by foxes. However, the way parasites affect pheasant vulnerability remains unclear.     

Impact of hand-rearing on morphology and physiology of the capercaillie (Tetrao urogallus)

Morphological and physiological disparities between 20 captive and 11 wild capercaillies were determined. Birds, their pectoral and leg muscles, hearts, livers and gizzards were weighed. The length of small intestines and caeca were measured. Haemoglobin, haematocrit, glucose, triglycerides, total protein, uric acid and thyroid hormones as well as the cytochrome c-oxidase activity of the pectoral muscle and heart were determined. The glycogen and protein contents of pectoral and leg muscles and liver were analysed. Chemical composition (water, fat, protein, ash) of muscles and liver was determined. Captive males had heavier pectoral muscles than wild ones. The result was opposite in females. Wild birds had heavier hearts, livers, and gizzards, and also longer small intestines and caeca than captive birds. The cytochrome c-oxidase activity of pectoral muscle and heart was higher in wild than in hand-reared birds. The chemical composition of livers of wild birds differed significantly from that of hand-reared capercaillies. Plasma uric acid and T(4) concentrations were higher in captive than in wild birds. The observed differences in digestive system and liver can result in diminished ability of captive birds to utilise natural food nutrients. Decreased cytochrome c-oxidase activity of hand-reared birds can affect their takeoff and flying capacity and increase their vulnerability to predation. These facts may contribute to the low survival of hand-reared birds after release.     

Ontogeny of behavior of hand-reared and hen-reared captive houbara bustards

The ontogeny of behavior of hand-reared and hen-reared captive houbara bustards (Chlamydotis undulata) was recorded between hatching and fledging and compared to determine ways to improve the behavioral and physiological health of individuals destined for release into the wild. Chicks from both groups were able to walk and run on the first day after hatching, although they were least active during the first 5 days. Thereafter, time spent prone with the head down, in a half-crouch position (resting on the tarsi) or being brooded during the day (in the case of hen-reared chicks), decreased quickly, and time spent walking and standing increased. Pecking and some preening and comfort behaviors were expressed from the first day in both groups, but increased after ˜15 days. Simple threat displays were first expressed at 6 days in both groups, but developed into more complete displays with age. The only differences found between the two rearing techniques were in time spent walking and in the half-crouch position: hen-reared chicks spent more time walking and less time in a half-crouch position than hand-reared chicks, because the hen stimulates the chicks to move. Lack of exercise during growth may result in poor development of locomotive structures, which may compromise the survival of chicks destined to be released to the wild. However, hand-reared juveniles were equally likely to survive as hen-reared juveniles after being released, suggesting that hen- rearing by captive-bred birds in a confined and artificial environment did not confer appreciable advantages. Zoo Biol 17:245–255, 1998. © 1998 Wiley-Liss, Inc.     

Translocation and early post-release demography of endangered Laysan teal

In an attempt to reduce the high extinction risk inherent to small island populations, we translocated wild Laysan teal Anas laysanensis to a portion of its presumed prehistoric range. Most avian translocations lack the strategic post-release monitoring needed to assess early population establishment or failure. Therefore, we monitored the survival and reproduction of all founders, and their first-generation offspring using radio telemetry for 2 years after the first release. Forty-two Laysan teal were sourced directly from the only extant population on Laysan Island and transported 2 days by ship to Midway Atoll. All birds survived the translocation with nutritional and veterinary support, and spent between 4 and 14 days in captivity. Post-release survival of 42 founders was 0.857 (95% CI 0.86–0.99) during 2004–2006 or annualized 0.92 (95% CI 0.83–0.98). Seventeen of 18 founding hens attempted nesting in the first two breeding seasons. Fledgling success was 0.57 (95% CI 0.55–0.60) in 2005 and 0.63 (95% CI 0.62–0.64) in 2006. The effective founding female population ( N _e) was 13. We applied these initial demographic rates to model population growth. The nascent population size increased to >100 after only 2 years post-release ( λ =1.73). If this growth rate continues, the size of the Midway population could surpass the source population before 2010.     

Covariation among demographic and climate parameters in whiskered auklets Aethia pygmaea

Annual survival rate and other demographic parameters of whiskered auklets Aethia pygmaea , a small planktivorous seabird, were measured at Buldir Island Alaska during 1992–2003 to provide comparative information for auk life history studies and to test for links among climate, age, productivity and survival. Using two 9  m mistnets, we captured and recaptured 384 adult and 193 sub-adult (one year old, a known-age component of our sample) birds as they arrived at the colony after dark during May and June (1,730  capture events). The best fitting model indicated a lower initial survival rate over the first year following marking (0.708±0.036 SE), and subsequent survival (mean 0.835±0.029) covarying with the Aleutian Low Pressure climate Index, with higher auklet survival in years with weak low pressure over the Aleutian Islands. Annual survival rate varied from 0.726±0.127 in 1998–99 to 0.994±0.077 in 1994–95, rates similar to those previously reported for least A. pusilla and crested auklets A. cristatella . A model based only on recaptures of known-age birds indicated a lower local survival estimate over the first year following marking (age one to two years), with no other age-effects on survival. Breeding propensity by age inferred from recaptures of birds with fully-developed brood patches that were originally marked as sub-adults (one year olds) indicated 53% breeding at age two, 94% breeding at age 3, 97% breeding at age 4 and 100% breeding thereafter. The sex ratio of the sampled birds was significantly male biased (60/40), likely due to differences in behaviour between males and females during the incubation stage. Taken together, our data indicate that whiskered auklet survival and productivity covaried with continuous variation in large-scale climatic conditions, the mechanism being either negative effects of stormy North Pacific weather or indirect effects on food supplies.     

Size matters: predation risk and juvenile growth in North Island brown kiwi (

This study investigated how predation risk in North Island brown kiwi changes as the birds grow and develop. Over a 10-year period, 53 adult and 126 young kiwi were radio-tagged at Lake Waikaremoana and studied to determine survival rates, causes of death, and rates of growth. Predation loss amongst adults was low (2.49% year^-1) and caused mainly by ferrets. Young kiwi suffered intense predation from stoats during their first four months of life, but thereafter became too large (> 800 g) for stoats to kill. Juveniles took at least 880 days to attain adult size, about four times longer than expected for a 2–3 kg bird. Growth rates peaked at about the point of hatch, rather than later on in development as in other birds. We suggest that a long evolutionary history dominated by resource limitation rather than predation may account for slow rates of development in kiwi, and that differences among kiwi species in their ability to persist in the presence of stoats are explained by differences in the time that they take to reach safe-size.     

Do radio collars influence mortality and reproduction? A case with ring-necked pheasants (<Emphasis Type="Italic">Phasianus colchicus</Emphasis>) in Central Italy

The effect of radio transmitters on bird survival and reproduction has been explored in the literature, and contradictory results were found. Using the Kaplan–Meier method, we estimated the mortality of female ring-necked pheasants (Phasianus colchicus) in relation to radio load (percentage of total body mass). Low-load birds showed a higher survival, particularly after 2–3 months from release, thus excluding short-term effects of handling and adjusting to packages. Reproductive success was higher for birds with low loads, but the effect was less clear. The results were not influenced by age or body mass. As a rule of thumb, using radio packages lighter than 1.5% of the body mass can be considered safe for pheasants, whereas loads above 2% may have adverse effects.     

Sexual segregation in winter, spring dispersal and habitat use in the pheasant (Phasianus colchicus)

Sexual segregation, spring dispersal and late winter to spring habitat selection were studied in the pheasant Phasianus colchicus L. on two areas for which the proportions of different habitats were similar. On one of the sites (Damerham) hand-reared pheasants were released for shooting. On the other (Fulwell) no releasing or shooting took place.
The sex ratio of birds feeding in fields in autumn favoured males because females fed in groups within woods. Groups of birds were significantly segregated by sex during early to late winter periods, but by late March they were not. Male groups and solitary males in winter were more evenly dispersed than female groups.
At Fulwell, female winter groups consisted of regular group members (mainly adults) and transitory individuals called 'drifters' (mainly immatures).
Females in their first breeding attempt dispersed further from their winter range to their breeding range than did adult females and females dispersed further than males. Males gaining a territory for the first time moved significantly further than old territory owners. Territorial males moved less than non-territorial males between successive spring ranges.
During March June, habitat use by 33 radio-tagged females changed markedly from mixed and deciduous woodland to fields sown with winter and spring corn. The implications for management are outlined.     

Reproductive ecology of Tibetan Eared Pheasant Crossoptilon harmani in scrub environment, with special reference to the effect of food

We studied the nesting ecology of two groups of the endangered Tibetan Eared Pheasants Crossoptilon harmani in scrub environments near Lhasa, Tibet, during 1996 and 1999–2001. One group received artificial food from a nunnery prior to incubation whereas the other fed on natural food. This difference in the birds' nutritional history allowed us to assess the effects of food on reproduction. Laying occurred between mid-April and early June, with a peak at the end of April or early May. Eggs were laid around noon. Adult females produced one clutch per year. Clutch size averaged 7.4 eggs (4–11). Incubation lasted 24–25 days. We observed a higher nesting success (67.7%) than reported for other eared pheasants. Provisioning had no significant effect on the timing of clutch initiation or nesting success, and a weak effect on egg size and clutch size (explaining 8.2% and 9.1% of the observed variation, respectively). These results were attributed to the observation that the unprovisioned birds had not experienced local food shortage before laying, despite spending more time feeding and less time resting than the provisioned birds. Nest-site selection by the pheasants was non-random with respect to environmental variables. Rock-cavities with an entrance averaging 0.32 m² in size and not deeper than 1.5 m were greatly preferred as nest-sites. The birds were also more likely to place their nests in denser high-scrub and closer to streams. In the study area, the low availability of both cliff habitats and high-scrub patches suggested a limitation of sites suitable for nesting, which could be reflected in the between-year re-use of nest-sites (8.9%) and intraspecific nest parasitism (3.8%). Despite the apparent preference for certain nest-site variables, we found no effect of these on clutch fate, suggesting that the risk of nest predation was random.     

Survival, site and mate fidelity in South Polar Skuas Catharacta maccormicki at Anvers Island, Antarctica

In 1974–1975, 34 adult South Polar Skuas Catharacta maccormicki were colour-ringed on 18 nest territories at Bonaparte Point, Anvers Island, near Palmer Station along the Antarctic Peninsula. Subsequently, the area was searched for these birds during the austral summers of 1975–1976 to 1984–1985 and in 1987–1988 and 1989–1990. Fifty-three percent were seen in 1984–1985, 32% in 1987–1988 and 21% in 1989–1990. Annual survival rate averaged 95% from 1974–1975 to 1984–1985; no sexual differences were detected (n = 28 of known sex). Strong territory and mate fidelity were apparent: 34 skuas averaged 1.1 nest territories and 1.7 mates each in 16 years. Only 4 of 34 individuals (all females) were known to change territories, and each territory change involved a change of mates. Although males showed higher territory fidelity than females (P < 0.01), most females (four of five) retained their territories when previous mates failed to return. Seventeen of 34 birds changed mates a total of 24 times; at least 20 mate changes followed the death or disappearance of the former mate. Males showed slightly higher mate fidelity than females (P < 0.04). Female South Polar and Brown Skuas Catharacta lonnbergi did not differ in territory or mate fidelity. From 1974–1975 to 1984–1985, 120 South Polar Skua chicks were ringed on 18 nest territories on Bonaparte Point: 17 were resighted in the Palmer area when they were 3–10 years old. All 15 returnecs were found within 3 km of their natal nest sites, and four of them occupied nest territories on Bonaparte Point.     

BREEDING OF THE WHITE-BACKED AND RÜPPELL'S GRIFFON VULTURES, GYPS AFRICANUS AND G. RUEPPELLII

The breeding season of two species of griffon vultures are described. Rüppell's Griffon Vulture lays 2–3 months earlier than the White-backed Griffon. Young birds were hand-reared to determine their food requirements during growth; these estimates were combined with the food requirements of adult birds to make an estimate of the amount of food a parent bird needs to obtain when it is rearing young. The amount of food actually obtained by a group of birds was recorded from the size of the crops of birds returning to the breeding colony in the afternoon. The comparison of the estimates of the food obtained and the food required through the breeding season suggested that there may be a period during rearing when there was insufficient food available to satisfy the food requirements of both chick and adult. Chicks were found to have a very high survival rate and were probably receiving sufficient food. Presumably adult birds were not therefore receiving sufficient food, and the examination of a sample of adult birds for body condition through the breeding season showed a clear decline in their fat deposits. It was considered that in both species, breeding was timed so that the young left the nest at a period in the year when food conditions were good and the young birds could feed with little competition from adults. The parent birds therefore had to rear young during a season in the year when food conditions were not always adequate and they had to rely on utilising fat reserves. The food conditions for vultures during this study were probably favourable and during years of food shortage breeding may become impossible, or restricted to the most aggressive and dominant individuals.     

Longevity and migration distance differ between wild and hand-reared mallards Anas platyrhynchos in Northern Europe

The mallard Anas platyrhynchos is the world’s most widespread and numerous dabbling duck. It is also farmed and released to the wild by the millions each year, but the effects of this on wild populations remain little studied. By using historical national ringing–recovery data from Sweden and Finland, we here address three predictions based on previous studies: (1) longevity is higher in wild than in hand-reared mallards, (2) wild mallards migrate longer than hand-reared, and (3) migration distance in wild ducks surviving long enough to start fall migration has decreased over the last 50 years. Indeed, wild mallards lived longer than hand-reared (19 versus 9 months in Swedish birds and 13 versus 4 months in Finnish birds). Compared to wild mallards, a smaller proportion of hand-reared birds survived long enough to have the chance to enter the wild breeding population; less than 25 % of the Swedish birds and less than 10 % of the Finnish birds lived a year or longer. Wild birds migrated farther than hand-reared (mean distance in Swedish birds, 676 versus 523 km; in Finnish birds, 1,213 versus 157 km), a pattern caused by both shorter life span and lower migration speed in hand-reared birds. Mean migration distance in wild Swedish mallards was 787 km in 1947–1972 but 591 km in 1977–1993. This difference was not statistically significant, though, possibly due to the limited sample size and lack of data from the last two decades. In general, our study provides a conservative test of the predictions addressed, calling for more research about the consequences of restocking duck populations.     

Early nutrition causes persistent effects on pheasant morphology

Differences in growth conditions during early ontogeny have been suggested to cause permanent effects on the morphology and quality of birds. Yearly variation in growth conditions could thus result in morphological and quality differences between cohorts. In this study, we investigated the effect of small differences in the dietary protein content of captive ring-necked pheasants (Phasianus colchicus) during their first 8 wk posthatching. An experimental increase of the proportion of dietary protein during the first 3 wk of life accelerated growth, whereas a similar manipulation during the following 5 wk had only a limited effect. Compensatory growth during the postexperimental period equalized the size of chicks from different experimental treatments. However, a difference in tarsus length resulting from experimental treatment during the first 3 wk remained into adulthood. Furthermore, the protein content of the diet during the first 3 wk had an effect on the degree of fluctuating asymmetry in tarsus length, suggesting persistent effects on the quality of birds. The results of this study may explain size differences between cohorts that exist in pheasants and may also provide a link between the use of pesticides in agriculture and population effects on pheasants.     

Growth and development of infant giant pandas (Ailuropoda melanoleuca) at the Wolong Reserve,China

From 1991 to 1993 inclusive, seven infant giant pandas (Ailuropoda melanoleuca) were born at the China Conservation and Research Center for the Giant Panda. Average daily weight gain in the first 6 months for mother-reared infants (n = 5) was 71.3 g/day; for one partially mother-reared and partially hand-reared infant, 41.5 g/day; and for one completely hand-reared infant, 50.3 g/day. There was a significant difference in growth rates across the first 6 months in all methods of rearing. In addition, a comparison of growth rates across the three rearing methods showed significant differences in the first, second, third, fifth, and sixth months. Average daily body length increase for mother-reared infants was 4.1 mm/day; for partially mother-reared/partially hand-reared infants, 4.0 mm/day; and for the completely hand-reared infant, 2.8 mm/day. In mother-reared infants, body length increase during the first month was significantly greater than during the following months, and was slowest during the sixth month. At birth, infants were all pink in color with a light white coat of lanugo. Black pigmentation was first noted at 7–10 days of age, which was also the time that initial hair coat growth was seen. Eyes opened at 35–48 days of age. Ears opened at 31–50 days of age. Deciduous dentition was first seen at 82–121 days of age, while permanent dentition began to erupt at 350 days of age. © 1996 Wiley-Liss, Inc.     

Conception rates following intrauterine insemination of European (Dama dama dama) fallow deer does with fresh or frozen-thawed Mesopotamian (Dama dama mesopotamica) fallow deer spermatoza

A total of 121 European fallow deer does, being either parous ( n = 15) or nulliparous ( n = 106), were treated with intravaginal progesterone impregnated controlled internal drug release (CIDR) devices for 14 days. The does were divided into three treatment groups and inseminated in utero by laparoscopy, at approximately 65 hours after CIDR device removal, with 25 × 10⁶ fresh Mesopotamian ( n = 40), 25–35 × 10⁶ frozen-thawed Mesopotamian ( n = 41) or 30–32.5 × 10⁶ frozen-thawed European ( n = 40) fallow deer spermatozoa. The semen used had been collected, from two Mesopotamian and two European fallow deer bucks, by electroejaculation under general anaesthesia. Pregnancy was diagnosed by rectal ultrasonogrdphy on Day 50 after insemination.
There were no apparent differences in the quality of ejaculates between the two subspecies of fallow deer. The volume of semen and the total number of spermatozoa ranged between 0.6–1.2 ml and 2.11–4.95 × 10⁹ per ml of semen, respectively. Evaluation of frozen-thawed spermatozoa revealed post-thaw motility rates between 50–70%. The overall conception rate was 65.3%. A higher conception rate was observed following insemination with European than Mesopotamian frozen-thawed spermatozoa (75% vs. 53.7%, respectively, P < 0.05). Insemination with fresh Mesopotamian spermatozoa increased the conception rate to a level not significantly different from that observed following insemination with European frozen-thawed spermatozoa (67.5% vs. 75%, for fresh Mesopotamian and frozen-thawed European semen, respectively).     

Trichurid nematodes in ring-necked pheasants from backyard flocks of the State of Rio de Janeiro, Brazil: frequency and pathology

The present investigation is related to the frequency of infection and to the gross and microscopic lesions associated to the presence of trichurid worms in 50 ring-necked pheasants (Phasianus colchicus) from backyard flocks in the state of Rio de Janeiro, Brazil. In the investigated birds, the overall infection rate was of 74%, with the presence of Eucoleus perforans with 72% of prevalence and 21.2 of mean intensity, in the esophageal and crop mucosa and rarely in the junction of the proventriculus and esophagus, E. annulatus with 2% and 3 in the crop mucosa, Capillaria phasianina, with 12% and 4.3 in the cecum and small intestine and Baruscapillaria obsignata, for the first time referred in this host, with 2% and 1 in the small intestine. Clinical signs were absent. The gross lesions observed in the crop and esophagus of 14 (38.9%) pheasants parasitized with E. perforans were thickening, small nodules, congestion, and petechial haemorrhages in the mucosa. These birds presented a mean infection of 37.5 and a range of infection of 10-82. The microscopic lesions revealed chronic esophagitis with diffuse inflammatory process in the lamina propria characterized mostly by a mononuclear cell infiltrate and also with the presence of granulocytes. In the case of the parasitism of pheasants with C. phasianina, the gross lesions were absent; microscopic lesions were characterized by chronic typhlitis with mononuclear infiltrate. Gross and microscopic lesions were absent in the pheasants parasitized with E. annulatus and B. obsignata.