Several animal species have recently been shown to have hybrid origins, but no avian examples have been documented with molecular evidence. We investigate whether the Audubon's warbler (Dendroica auduboni), one of four visually distinct species in the yellow-rumped warbler complex, has originated through hybridization between two other species in this group, the myrtle warbler (D. coronata) and...

Diseases caused by crown rust (Puccinia coronata f. sp. avenae) and powdery mildew (Blumeria graminis f. sp. avenae) are among the most important constraints for the oat crop. Breeding for resistance is one of the most effective, economical, and environmentally friendly means to control these diseases. The purpose of this work was to identify elite alleles for rust and powdery mildew resistance...

Hybrid zones between recently diverged taxa are natural laboratories for speciation research, allowing us to determine whether there is reproductive isolation between divergent forms and the causes of that isolation. We present a study of a classic avian hybrid zone in North America between two subspecies of the yellow-rumped warbler (Dendroica coronata). Although previous work has shown very l...

Avian brood parasites reduce the reproductive success of the host, which favours the evolution of antiparasitic defences, such as aggression towards parasites or rejection of their eggs. The red-crested cardinal, Paroaria coronata, is a potential good-quality host of the shiny cowbird, Molothrus bonariensis. However, the frequency of cowbird parasitism in cardinal nests is very low and there ar...

Despite the growing concern over reptile population declines, the effects of modern industrial silviculture on reptiles have been understudied, particularly for diminutive and often overlooked species such as small-bodied snakes. We created 4 replicated forest-management landscapes to determine the response of small snakes to forest harvesting in the Coastal Plain of the southeastern United Sta...

In a number of the avian species in which testicular development can be evoked by increased daily photoperiods it has been found that such development cannot be sustained indefinitely and that there is a period following each cycle of development during which increased daily photoperiods are ineffective. This period is commonly designated as the refractory period. Much of the available informat...

The role of extracellular fl-1,3-glucanases and chitinases was investigated in oat leaves after infection with different rust fungi . The oat leaves (Avena sativa L .) were inoculated with the compatible rust Puccinia coronata f. sp . avenae and the two nonpathogens Puccinia recondita f. sp . tritici and Puccinia graminis f. sp. tritici . No alterations in enzyme activities were found in the co...

A total of 234 helmeted guinea fowls, Numida meleagris coronata, were examined for lice at five localities in South Africa. These were the Mountain Zebra National Park in the eastern Karoo, Cape Province; the Andries Vosloo Kudu Reserve and the farm Bucklands, in Valley Bushveld, eastern Cape Province; the Bontebok National Park, south-western Cape Province; and the southern part of the Kruger ...