Supplementing a grain diet with insects instead of fruits sustains the body condition of an omnivorous bird.

Omnivores utilize dietary sources which differ in nutrients, hence dietary limitations due to environmental change or habitat alteration could cause nutrient limitations, and thus deterioration of body condition if omnivory is obligate. We investigated how the body condition of the omnivorous Village weaver Ploceus cucullatus (weavers), which forages predominantly on grains, responds to the supplementation of its grain diet with insects instead of fruits. Forty wild-caught weavers held in aviaries were fed a combination of grains and fruits, or grains and insects ad libitum for 8 weeks. We determined diet preference by recording the number of birds on each diet option per minute for 1 h and the amount of food left-over after 3 h of foraging. Fortnightly, we assessed indices of body condition including body mass, pectoral muscle, and fat scores, packed cell volume (PCV), and hemoglobin concentration (HBC). We modeled the number of foragers, food left-over, and body condition indices as functions of diet, while accounting for time (weeks) and sex effects. Grains were the preferred diet, but males ate more fruits and insects than females. Weavers fed on grains and fruits lost body and pectoral muscle mass and accumulated less fat than those fed on grains and insects. This effect was sex-dependent: females supplemented with fruits lost more pectoral muscle mass than males of the same group and males but not females, supplemented with insects accumulated more fat reserve than those supplemented with fruits. PCV and HBC did not differ between diets but increased over the 8 weeks. Weavers are likely obligate rather than facultative omnivores, with insects as being a more nutritive supplement than fruits. Nutrient limitation arising from environmental change or habitat alteration could impair body condition and affect physiological function to environmental seasonality in obligate omnivores like the weavers.

Avian haemosporidians in the cattle egret (Bubulcus ibis) from central-western and southern Africa: High diversity and prevalence.

We described the geographic distribution of 82 haemosporidian lineages (Plasmodium, Haemoproteus, and Leucocytozoon) in the cattle egret sampled in five countries in central-western and southern Africa. Seventy-three lineages have not previously been reported. We determined the prevalence of three haemosporidians in the samples. We investigated the influence of the internal environment of the host and environmental variables on the Plasmodium diversity and whether environmental variables may explain spatial variations in the prevalence of Plasmodium. We screened DNA from 509 blood samples from nestlings in 15 African colonies for infection by sequencing the cytochrome b gene of parasites. The molecular phylogenetic analysis was performed using Bayesian methods and including sequences from the MalAvi and GeneBank databases. We found 62 new Plasmodium lineages in a clade with MYCAME02, which is a lineage described in waterbirds and recently identified in birds of prey as Plasmodium paranucleophilum. Two Haemoproteus lineages identified in cattle egret formed a distinct group with Haemoproteus catharti and MYCAMH1 (Haemoproteus spp.). Seven Leucocytozoon lineages found in the cattle egret clustered with Leucocytozoon californicus. We found different Plasmodium diversities among the colonies sampled, demonstrating that the internal environment of the host is not the primary determinant of diversity. A linear mixed-effects multivariate model showed that precipitation was positively associated with Plasmodium diversity when controlling for the effects of temperature, colony composition (mixed and non-mixed species) and country. Moreover, a generalized mixed model showed that temperature was positively associated with the prevalence of Plasmodium when controlling for precipitation, elevation and country. We conclude that the cattle egret is a good model for future haemosporidian studies, as we found a significant number of new lineages in this host, which occupies regions with different climate characteristics where environmental variables exert an influence on the diversity and prevalence of Plasmodium.

Situation-based survey of avian influenza viruses in possible "bridge" species of wild and domestic birds in Nigeria.

The highly pathogenic avian influenza (H5N1 subtype) recurred in Nigeria after 9 months period of no reported case. A critical look at possible sources of the re-occurrence was desirable. The objective of this study was to determine whether avian influenza viruses were present at reasonably detectable levels (0.5%) in possible "bridge" species of wild and domestic birds. The study was conducted in 8 Nigerian states. A total of 403 birds from 40 species were sampled. Virus isolation was done in embryonated chicken eggs according to standard protocols. The test results were all negative for avian influenza viruses. The overall confidence interval (CI) calculated in R using the exact binomial confidence interval function was 0-0.007406. Tawny Eagle (Aquila rapax) was the lowest sampled 0.3% (1/403) and Red-billed Firefinch (Lagonosticta senegala) the highest 11.7% (47/403). The limitations of the sample size and possibly designing effects on the study, as to make concrete conclusions were acknowledged. Species of wild birds, so identified in the study could be useful in future surveys. Furthermore, multidisciplinary and community oriented approach, blending targeted and passive surveillances was suggested. This approach was envisaged to bring about wider coverage of "bridge" species and clearer insight of their possible roles in avian influenza re-occurrences and spread in Nigeria.