Factors influencing reproductive performance of northern bobwhite in South Florida

Reproductive success is a critical component of individual fitness, and also an important determinant of growth rates of populations characterized by early maturity and high fecundity. We used radiotelemetry data collected during 2003–2008 to estimate reproductive parameters in a declining northern bobwhite (Colinus virginianus) population in South Florida, and to test hypotheses regarding factors influencing these parameters. The overall clutch size was 12.10 ± 0.22, but females laid more eggs in their first clutch (12.43 ± 0.24) than in subsequent clutches (10.19 ± 0.53) within a nesting season. Daily nest survival was higher for first (0.966 ± 0.003) than subsequent nests (0.936 ± 0.011). Hatchability (proportion of laid eggs that hatched conditional upon nest survival to hatching) was 0.853 ± 0.008, but was higher for nests incubated by females (0.873 ± 0.009) than those incubated by males (0.798 ± 0.018). The proportion of individuals attempting a second nest was 0.112 ± 0.024 and 0.281 ± 0.040 when the first nest was successful and failed, respectively. Hatchability was lower when the nesting habitat was burned the previous winter. We found no evidence that food strip density (a management practice to provide supplemental food) influenced any of the reproductive parameters. Mean summer temperature affected hatchability, nest survival, and proportion of nests incubated by males. Overall, the reproductive output in our study population was lower than that reported for most other bobwhite populations, indicating that low reproductive performance may have contributed to bobwhite population declines in our study site. These results suggest that current management practices, particularly those related to habitat and harvest management, need careful evaluation.     

Optimal group size and northern bobwhite coveys

Northern bobwhite, Colinus virginianus, form social units, called coveys, during the nonbreeding season (approximately September-April). Because the evolutionary advantage of this behaviour is generally unknown, we used controlled group size manipulations within an aviary to investigate whether group size influences (1) the time that the covey spends feeding, (2) the percentage of the covey that is vigilant, (3) the overall vigilance of the group and (4) the time to predator detection. We found that increasing group size increased the time that coveys spent in an exposed feeding area, reduced individual vigilance, improved group vigilance and decreased the time to detection of a potential predator. Additionally, we used experimental reductions of wild northern bobwhite coveys to test whether groups size influences (1) individual and covey survival, (2) daily movement in maintaining covey size and (3) mass change. We conducted field research on 12 independent 259-ha study areas (6 control plots and 6 treatments, where 60% of the population was removed) in east-central Kansas, U.S.A. between 9 November and 31 January, 1997-2000. We radio-marked 386 radiocollared individuals that comprised 137 groups on the study areas. Covey size did not differ between or within years or treatments (X±SE: 10.98±0.22 individuals). Our results indicate that a stable group size existed between 1 and 22 individuals, with 11 being an optimal group size. Small coveys (1-7 individuals) had lower group persistence and individual survival, and used increased movement to create or join larger groups where survival was higher. Large groups (15-22) had lower individual survival, increased group movement and individual mass loss. Density-dependent feedbacks (e.g. lower survival and increased competition) may have lowered larger coveys to a stable size. Our results suggest the regulation of an optimal covey size of 11 was promoted by high group persistence, low group movement, improved feeding efficiency, improved individual predator detection and improved individual survival. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.      

Gastrointestinal helminths of free-ranging Florida panthers (Puma concolor coryi) and the efficacy of the current anthelmintic treatment protocol

Thirty-five Florida panthers (Puma concolor coryi [Bangs, 1899]) collected from six counties in southern Florida between 1978 and 2003 were examined at necropsy for gastrointestinal helminths. The panthers were placed into two groups: 1) treated with anthelmintics (n = 17), and 2) untreated (n = 18). Nine species of helminths (one trematode, six nematodes, and two cestodes) were identified in the untreated panthers. The most prevalent helminths were Alaria marcianae (LaRue, 1917) (100%), Spirometra mansonoides (Mueller, 1935) (91%), and Ancylostoma pluridentatum (Alessandrini, 1905) (89%). Ancylostoma caninum (Ercolani, 1859) is reported from the Florida panther for the first time. The intensities of helminths with prevalences >10% did not differ between untreated panthers collected in 1978-1983 and 1996-2003. Treated panthers had helminth faunas similar to those of untreated panthers. The current anthelmintic treatment being used reduced the intensity of both A. marcianae and A. pluridentatum in panthers < or =6 mo posttreatment (PT); however, treated panthers between 6 and 9 mo PT, and >9 mo PT were similar to untreated panthers. Treatment was less effective on S. mansonoides and Taenia omissa Lühe, 1910. Treated panthers had slightly lower intensities of S. mansonoides at < or =6 mo PT; however, between 6 and 9 mo PT and >9 mo PT they had significantly higher intensities than untreated panthers. At all periods PT, the intensity of T. omissa for the treated panthers was similar to that of untreated panthers. We suggest that Mesocestoides sp. may not be present in the Florida panther population as reported earlier by Forrester et al. (1985), due to parasite misidentification by those authors.     

Effects of fire management on northern bobwhite brood ecology

Northern Bobwhite Colinus virginianus chicks require ample invertebrates for growth and feather development. Early successional or resprouting vegetation provides invertebrates for chicks but may not provide other resources such as roosting and loafing cover that is typically provided by later successional stages. Thus, management for bobwhites provides multiple seral stages in close proximity but the effects of landscape interspersion have not been tested for bobwhite broods. During a 2-year study, we explored the effects of landscape complementation and food availability on growth and survival of bobwhite chicks. We found growth of chicks to be negatively related to home range size which was negatively correlated to the amount of area burned. We also found survival of chicks to be positively related to the amount of burned area (i.e., foraging area) within brood home ranges. To maximize the growth and survival of bobwhite chicks, it would be necessary to increase access to foraging areas while decreasing the size of brood home ranges. Access to foraging areas can be created through frequent prescribed fire at small spatial scales.     

Gastrointestinal helminths and protozoa from two raccoon populations in Kansas

A survey in Kansas compared the prevalence of gastrointestinal helminths and protozoa in 2 raccoon (Procyon lotor) populations; a population in a typical rural setting and a relatively undisturbed population on a military reservation. Gastrointestinal tracts of 128 raccoons were examined. Freeze storage of alimentary tracts prevented collection of data on trematode prevalence. Helminth infections other than trematodes included 1 acanthocephalan, 2 cestodes, and 3 nematodes. Helminths were found in all raccoons from the population on the military installation and 96% of those from the rural population. Prevalence of helminths was generally greater in raccoons from the population living in the rural setting. Eimeria spp. and Sarcocystis sp. were also found, whereas Giardia spp. and Cryptosporidium parvum were not.     

Subspecies and units for conservation and management of the northern bobwhite in the eastern United States

The northern bobwhite (Colinus virginianus) is a small game bird with sedentary lifestyle and has experienced population declines throughout most of its native distribution in the eastern United States. We investigated intraspecific genetic relationships among 14 local populations covering four putative subspecies (C. v. marilandicus, C. v. virginianus, C. v. mexicanus, and C. v. floridanus) in the United States. Analysis of mitochondrial DNA sequences revealed a small, but significant, genetic structure of northern bobwhite populations or subspecies in the eastern US. However, our results did not support current subspecies limits as distinct evolutionarily significant units, based on the amount of population genetic divergences and insufficient lineage sorting of mtDNA haplotypes among subspecies. Instead, our results suggest that C. v. virginianus, C. v. marilandicus, and C. v. mexicanus be merged into a single management unit, and C. v. floridanus be considered as another distinct unit for conservation and management.     

Heterosynapsis and axial equalization of the sex chromosomes of the northern bobwhite quail.

The pairing behavior of the Z and W chromosomes in the female northern bobwhite quail (Colinus virginianus) was analyzed by electron microscopy of silver-stained synaptonemal complexes (SCs). After autosomal pairing was completed, synapsis of the sex chromosomes initiated at the short-arm end of the W chromosome and one end of the Z chromosome. Synapsis then progressed unidirectionally, producing a sex bivalent in which the entire length of the W axis was paired with an equivalent length of the Z axis. Progressive contraction and asymmetrical twisting of the Z axis ultimately resulted in a fully paired configuration with aligned axial ends. Further contraction of the Z axis reduced the extent of asymmetrical twisting such that only the nonaligned centromeric regions distinguished the SC of the ZW bivalent from SCs of similar-sized autosomes in late-pachytene nuclei. Quantitative analyses indicated that the length of the Z axis shortened significantly during the adjustment process, whereas no significant difference occurred in the length of the W axis. The nonalignment of the centromeric regions during transitional stages of ZW synapsis indicates that direct heterosynapsis of nonhomologous segments, followed by axial equalization of the length inequality, is responsible for the length adjustment during synapsis in the sex chromosomes of the bobwhite quail.     

Aflatoxin production in supplemental feeders provided for northern bobwhite in Texas and Oklahoma

Mycotoxins are toxic metabolites produced by varous species of fungi. Aflatoxin (AF), a particular type of mycotoxin, can negatively impact many wildlife species in the laboratory; however, the magnitude of the problem in the field environment is unclear. Wild birds generally consume a combination of native foods and agricultural grains. A common practice in which birds, such as northern bobwhite (Colinus virginianus), contact stored agricultural grain is through supplemental feeding. This feeding practice may promote the production of AF. The objectives of this study were to (1) examine AF production in supplemental feeders and (2) examine the relationship between weather and AF production in supplemental feeders. Samples were collected from supplemental feeders from November through February of 1996-97 and 1997-98. Mean monthly AF concentration of samples from feeders ranged from 0.57+/-2.86 to 15.47+/-14.69 ppb. Aflatoxin concentration in supplemental feeders increased from pre-sample to one month after filling the feeders each year. AF production in supplemental feeders was highly variable among months with no real temporal pattern between years. Instead, AF production was related to the highly variable relative humidity of the study area which influences moisture content of grain. Average relative humidity can be used to predict AF production.     

Gastrointestinal helminths of the lizard Chalcides ocellatus from Benghazi, Libya

Chalcides ocellatus, a scincid lizard, sampled during October 1998 to December 1999 from Benina (farmland) and Al-Kueffia (a rocky area) in Benghazi, Libya, was found to harbour three intestinal nematodes, Pharyngodon mamillatus, Thelandros alatus and Parapharyngodon micipsae, and an intestinal cestode, Oochoristica tuberculata. Thelandros alatus, P. micipsae and O. tuberculata were recorded for the first time in C. ocellatus. Parapharyngodon micipsae was detected in C. ocellatus from Benina and O. tuberculata from lizards in Al-Kueffia. The majority (87.6%) of C. ocellatus were infected with helminth parasites and the levels of infection were higher in males than in females but this difference was not significant. Pharyngodon mamillatus recorded the highest number of nematode parasites in C. ocellatus, although there was no relationship between the number of nematode parasites recovered and host density. In lizards infected with the cestode O. tuberculata, males had shorter snout-vent lengths than females. From a total of 153 C. ocellatus, 120 (78.4%) showed single and 14 (9.2%) showed mixed parasitic infections. Mixed infections between different species of nematodes were not observed.     

Gastrointestinal helminths of Risso's dolphin Grampus griseus from the Western Mediterranean

The gastrointestinal helminth fauna of 17 Risso's dolphins Grampus griseus (Cuvier, 1812) from the Western Mediterranean was analysed. Five helminth species were found. Adults and juveniles of Hadwenius delamurei were collected from the duodenum of 7 animals. Adults were located significantly more anteriorly than juveniles, which is compatible with a previous hypothesis that species of Hadwenius undergo an ontogenetic migration towards the anterior duodenum. Eggs from Pholeter gastrophilus appeared in 1 small cyst in the main stomach. Adults of Tetrabothrius forsteri and Trigonocotyle globicephalae were collected from the duodenum of 1 and 4 individuals, respectively. Metacestodes, Scolex pleuronectis, were found in the liver, pancreas, pyloric stomach and intestine of 13 individuals. The most favored locations were in the mucosa of the terminal colon and in anal crypts. It is likely that worms select these locations to reach the mesenteries and blubber of the anogenital area, where S. pleuronectis might become Monorygma and/or Phyllobothrium. Two individuals of Stenurus globicephalae occurred in the intestine of 1 individual, and were probably swallowed accidentally. The intestinal helminth communities of Risso's dolphin are depauperate. The parasite species found also occur in other oceanic cetaceans from the Western Mediterranean. However, H. delamurei and T. globicephalae are only shared with pilot whales Globicephala spp., which are phylogenetically closely related to Risso's dolphins.     

Parasitic helminths of Eurasian collared-doves (Streptopelia decaocto) from Florida

Sixty-three Eurasian collared-doves (ECDs) (Streptopelia decaocto) from Florida were examined for parasitic helminths from June to December 2001. Nine species of helminths were identified (5 nematodes, 2 cestodes, and 2 trematodes). The most prevalent helminths were Ascaridia columbae (73.0%), Fuhrmannetta crassula (28.6%), Ornithostrongylus quadriradiatus (12.7%), and Bruscapillaria obsignata (11.1%). The helminths with the greatest mean intensity were Tanaisia bragai (13.5), A. columbae (9.3), and O. quadriradiatus (7.1). In Florida, the mean intensity of A. columbae in ECDs (9.3) was similar to that found in white-winged doves (Zenaida asiatica) (9.1) (P = 0.461), and both the intensities were significantly higher than that in the native mourning doves (Zenaida macroura) (3.7) (P = 0.001 and 0.005, respectively). Fuhrmannetta crassula is reported for the first time in columbids from Florida.     

Gastrointestinal helminths of fish-eating birds from Chiloe Island, Chile

Of four species of fish-eating birds from Chiloé Island (Chile), three were infected with eight species of helminths. Tetrabothrius sp. was found in Larus scoresbii. Tetrabothrius cylindraceus, Profilicollis antarcticus, Anomotaenia dominicanus, Stephanoprora denticulata, Capillaria sp. and P. antarcticus were found in Larus dominicanus. Contracaecum rudolphii and Corynosoma sp. infected Phalacrocorax olivaceus. With the exception of S. denticulata, C. rudolphii and Capillaria sp., the above helminths are reported for the first time from Chile.     

Trophic transfer of methyl mercury in the northern Florida Everglades

There are spatial differences in methyl mercury (MeHg) concentrations in biota in Water Conservation Areas 2 and 3 in the Everglades, with higher concentrations generally found in the southern areas. Fish and hemipterans had the most MeHg on a wet weight basis, with levels exceeding 30 ng g^-1. The magnitude of MeHg accumulation in biota varies seasonally and does not always appear to be associated with changes in water column concentration. This is exemplified by periphyton, the base of the foodweb in the Everglades, at a high nutrient sampling site. Although limited in scope, MeHg concentrations presented for biota provide insight into beginning to understand the dynamic nature of Hg transfer in the Everglades foodweb on a spatial and temporal basis.     

Pathogenicity of Eimeria lettyae Ruff, 1985 in the northern bobwhite (Colinus virginianus L.)

Sporulated oocysts of Eimeria lettyae were administered orally to 5-day-old or 18-day-old northern bobwhites (Colinus virginianus, L.). Five-day-old bobwhites were more susceptible based on higher mortality and reduced weight gain. A dose of 5 X 10(5) oocysts produced 25-43% mortality in 5-day-old bobwhites, but none in 18-day-old bobwhites. A dose of 1 X 10(6) oocysts/bobwhite produced 83-100% mortality in 5-day-old bobwhites, and 17-83% mortality in 18-day-old bobwhites. Body weight gain was reduced significantly with a dose of 1 X 10(5) oocysts or greater in 5-day-old bobwhites and with a dose of 5 X 10(5) oocysts or greater in 18-day-old bobwhites. Infection in all age groups reduced concentrations of plasma pigment and plasma protein, but did not affect packed cell volumes. No grossly visible lesions were present in the intestine although there was a shortening of the villi in the duodenum. In mature bobwhites, infection with E. lettyae did not cause mortality, but did reduce egg production and fertility.     

Ecology of helminth parasitism in bobwhites from northern Florida

Examination of 700 northern bobwhites (Colinus virginianus), 50 each February from 1971 through 1984, from Tall Timbers Research Station, Leon County, Florida, disclosed 15 species of helminth parasites. Nine species (Raillietina cesticillus, R. colinia, Aproctella stoddardi, Cheilospirura spinosa, Cyrnea colini, Dispharynx nasuta, Heterakis isolonche, Tetrameres pattersoni, and Trichostrongylus tenuis) generally were found on an annual basis and were considered characteristic components of the helminth fauna. Infrequently found species were Brachylecithum nanum, Rhabdometra odiosa, Capillaria sp., Gongylonema ingluvicola, H. gallinarum, and Oxyspirura matogrosensis. Intensities of C. colini and H. isolonche differed among host sex and age classes, and prevalences and/or intensities of A. stoddardi, C. spinosa, T. pattersoni, and T. tenuis differed between host age classes. Prevalences and/or abundances of seven species (R. cesticillus, R. colinia, C. spinosa, C. colini, H. isolonche, T. pattersoni, and T. tenuis) varied with bobwhite density, apparently because bobwhites were either the primary or only definitive host on the area. Two species (A. stoddardi and D. nasuta) did not vary with bobwhite density, apparently due to the buffering effect of a broad range of definitive hosts on the area. Prevalences and/or intensities of R. colinia, C. spinosa, and T. tenuis differed with agricultural fields status (cultivated versus fallow) suggesting that land use and its attendant habitat changes influenced transmission of these species. The occurrence of C. spinosa and T. pattersoni in individual bobwhites was not independent and was attributed to utilization of the same species of grasshoppers as intermediate hosts. Localized tissue damage and inflammation were associated with A. stoddardi, D. nasuta, C. spinosa, C. colini and T. pattersoni. Decreases in body weight in juvenile bobwhites were associated with increasing intensities of H. isolonche and T. tenuis. The observed relationships to bobwhite density and other variables are discussed with regard to known aspects of life histories of the nine most common species.     

Parasitic helminths of red-bellied woodpeckers (Melanerpes carolinus) from the Apalachicola National Forest in Florida

Seventy-four red-bellied woodpeckers (Melanerpes carolinus) from the Apalachicola National Forest (30 degrees 10'N, 84 degrees 40'W) in northwest Florida were examined for helminths. The most prevalent parasites were the nematode Aproctella stoddardi (11%) and the acanthocephalan Mediorhynchus centurorum (11%). New host records include Pseudaprocta samueli, A. stoddardi, Tridentocapillaria tridens, Diplotriaena americana, Dispharynx nasuta, Procyrnea pileata, Orthoskrjabinia rostellata, and Brachylaima fuscatum. The helminth fauna was characterized by low prevalences and intensities of infection and low numbers of species per bird (1.2). The frequency of prescribed burning and habitat understory flora composition did not influence the prevalences or intensities of helminths in red-bellied woodpeckers collected from 2 similar but differently managed sites within the forest.     

Evaluation of host preferences by helminths and ectoparasites among black-tailed jackrabbits in northern California

Fifty-four black-tailed jackrabbits (Lepus californicus) (five juvenile males, 22 adult males, five juvenile females, and 22 adult females) from Humboldt County, California (USA) were evaluated for sex and age-specific differences in parasite prevalences and intensities, 26 February through 30 October 1996. Nematodes found included Biogastranema leporis in 42 hares (78% prevalence), Rauschia triangularis in 26 hares (48%), Trichostrongylus calcaratus in 14 hares (26%), and Trichuris sylvilagi in two hares (4%). Cestodes found included Taenia sp. cysticerci in five hares (9%) and Taenia sp. coenurus found in one hare (2%). Ectoparasites found included the ticks Dermacentor variabilis on 10 hares (19%) and Ixodes spinipalpis (= Ixodes neotomae) on nine hares (17%), as well as the anoplurid louse Haemodipsus setoni on 12 hares (22%). No significant differences in the parasite prevalences or intensities were found between male and female jackrabbits; this was for all males and females collectively, juvenile males and females only, as well as adult males and females only. Combining male and female hosts, adult jackrabbits had a significantly higher prevalence of B. leporis and R. triangularis compared to juveniles. This is the first known report of Trichostrongylus calcaratus, Rauschia triangularis, Trichuris sylvilagi, and Dermacentor variabilis among black-tailed jackrabbits and the first known report of T. calcaratus and T. sylvilagi in the western USA. This is the first published report of I. spinipalpis, the vector for Lyme disease in California, on black-tailed jackrabbits.     

Parasitic helminths of free-ranging mink (Neovison vison mink) from southern Florida

Five free-ranging mink, Neovison vison mink, from in or near the Fakahatchee Strand Preserve State Park, Collier County, Florida (26 degrees 00'N, 81 degrees 25'W), were examined for parasitic helminths. Nine species of helminths were identified (2 trematodes, 5 nematodes, and 2 acanthocephalans). The most prevalent parasites were Molineus patens (4 of 5 mink), mean intensity 173 (range, 12-342); Strongyloides sp. (4 of 5), mean intensity 48 (range, 1-170); Macracanthorhynchus ingens (immature) (4 of 5), mean intensity 2.5 (range, 1-4); and Alaria mustelae (3 of 5), mean intensity 59.3 (range, 11-127). Polymorphus brevis and Dirofilaria lutrae are reported from the mink for the first time.     

Gastrointestinal helminths of Cuvier's beaked whales, Ziphius cavirostris, from the western Mediterranean

We examined the gastrointestinal helminth fauna of 2 Cuvier's beaked whales, Ziphius cavirostris, stranded on the Spanish Mediterranean coast. Information regarding intestinal parasites of this species is provided for the first time. Six helminth taxa were identified. Thirty type II larvae of the nematode Anisakis sp. were found in the stomach and the intestine of both hosts; 2 type I larvae of Anisakis sp. were found in the intestine of 1 host. One juvenile of the acanthocephalan Bolbosoma vasculosum was found in the intestine; the metacestode Scolex pleuronectis was found mainly in the terminal colon and the anal crypts of both hosts; adult cestodes of Tetrabothrius sp., which may represent a new species, were collected from the duodenum of 1 host. Composition of the intestinal parasitic community is similar to that of other oceanic cetaceans, which mostly include species of Bolbosoma and tetrabothriids (Cestoda).