a participatory rural appraisal technique (prat) was used to obtain information from 132 randomly selected turkey farmers in two out of four agricultural development zones in kwara state, nigeria. data were obtained on socio-occupational status of farmers, their production objectives, experience, flock structure, management practices, marketing and consumption of turkey eggs. the results showed...

The traditional explanation for interspecific plumage colour variation in birds is that colour differences between species are adaptations to minimize the risk of hybridization. Under this explanation, colour differences between closely related species of birds represent reproductive character displacement. An alternative explanation is that interspecific variation in plumage colour is an adapt...

The evolution of bird plumage colouration may be explained by a wide range of selective pressures, including both defensive and advertising needs. However, the relationship between plumage colouration and body size has never been investigated in detail. Here we hypothesize that body size represents a constraint for the evolution of plumage colour heterogeneity because the relative number of bod...

BACKGROUND Plumage coloration is important for bird communication, most notably in sexual signalling. Colour is often considered a good quality indicator, and the expression of exaggerated colours may depend on individual condition during moult. After moult, plumage coloration has been deemed fixed due to the fact that feathers are dead structures. Still, many plumage colours change after moult...

Most studies investigating the function and evolution of ornaments have focused on males. Variation in ornaments may also reflect individual quality and convey information in females. We examined correlations between female plumage colour and reproductive variables in the sexually dichromatic songbird, the American Redstart (Setophaga ruticilla (L., 1758)). Female American Redstarts display yel...

Sexually selected ornaments often function as condition-dependent signals of quality (or 'indicators'). When ornamentation is costly, only high-quality individuals can afford to produce the most elaborate signals. The plumage ornamentation of male red-billed queleas, Quelea quelea, is an ideal candidate for an indicator because it is continuously variable, conspicuous, sexually dimorphic, is di...

The ecological effects of global climate changes include shifts of species' distribution and changes in migration strategies and phenotype. Colour polymorphism, which can be envisaged as a species' evolutionary response to alternating conditions or to a wide range of habitats, may be affected by climate changes as well. The scops owl (Otus scops) shows two main colour morphs, dark- and pale-red...

Red plumage is produced mainly by deposition of carotenoid pigments into the feathers and is assumed to be costly. Recent studies suggest red plumage may be a condition-dependent, sexually selected signal. To date, few studies have explored the relationship between carotenoid-based plumage colour and genetic (realised) reproductive success. This is despite the rarity of genetic monogamy among a...

Studies of the patterns of diversification of birds on islands have contributed a great deal to the development of evolutionary theory. In white-winged fairy-wrens, Malurus leucopterus, mainland males develop a striking blue nuptial plumage whereas those on nearby islands develop black nuptial plumage. We explore the proximate basis for this divergence by combining microstructural feather analy...

The present study was conducted to determine egg production traits and egg quality characteristics in black and brown lines of Japanese quail. A total of 500 quails comprising 400 females and 100 males obtained from two breeding centers were raised according to the standard procedure for Japanese quail. They were grouped in according to their plumage colours. Age at first egg-laying has been re...