Understanding the mechanisms that influence variation in sexually selected ornaments in seabirds has been challenging owing to the difficulty of capturing and sampling individuals outside of the breeding period when ornaments are usually grown. Stable carbon (dC) and nitrogen (dN) isotopes were used to examine the influence of pre-breeding diet composition on ornament size in the Rhinoceros Auk...

Light stimulation before hatching initiates the emergence of avian visual lateralisation. Since several studies show that birds benefit from being lateralised, we can conjecture that their clutch is being exposed to light during breeding. We tested this assumption in pigeons with a semi-natural setup where the animals were systematically recorded using a movement detection system throughout the...

—The Yellow Warbler (Dendroica petechia) has a mating system characterized by monogamy and biparental care, and has the broadest breeding distribution of any Dendroica species. When faced with a short breeding season and unpredictable conditions at high latitude, they display physiological responses to help optimize the tradeoff between individual risk and reproductive success. Because these ci...

This study was aimed to evaluate the effect of GnRH injection on semen ejaculate characteristics in Awassi rams collected in breeding and non breeding seasons. The study was conducted in late summer to early autumn when breeding activity commences, and in winter during the non breeding season. Twelve mature Awassi rams were used in this study. Animals were randomly allocated into two equal grou...

Cows not conceiving will return to estrus again beginning about 18 to 25 days after the synchronization period. The females will still be synchronized to a slight degree, which gives a second chance to artificially inseminate each female in the early part of the breeding season. Without synchronization, the herd manager is faced with a 21-day period of continual estrus detection and only one op...

Coyote (Car1i.s1ntran.s)depredation is a chronic problem for sheep producers in the western United States. Due to increasingly localized control efforts, behaxior of individual coyotes in sheep-ranching entironments is becoming a more important consideration. We radiotracked 14 coyotes on a year-round sheep-ranching facility in north-coastal California during September 1993-December 1995. Breed...

Phenological studies have demonstrated changes in the timing of seasonal events across multiple taxonomic groups as the climate warms. Some northern European migrant bird populations, however, show little or no significant change in breeding phenology, resulting in synchrony with key food sources becoming mismatched. This phenological inertia has often been ascribed to migration constraints (i....

the data of this study were collected by indigenous chicken breeding centers in the west azerbaijan for 11 generations. the (co) variance components, heritability's, correlations between traits and breeding values were estimated by multi-trait animal model using wombat software. the genetic trends of traits over 11 generations of selection, using average function of breeding values per gen...

Th e energetically challenging periods of molting and breeding are usually temporally separated in temperate birds, but can occur simultaneously in tropical birds, a condition known as molt – breeding overlap. Here, we document great variation in the timing and duration of molting and breeding, and in the extent of molt – breeding overlap, among 87 species of understory passerines in central Am...

Non-point source pollution is widely considered a serious threat to drinking water. Eutrophication in Chinese watershed is mainly due to nitrogen and phosphorus output from agricultural source. Taihu Lake is a typical eutrophic lake in China, a basin representative for the study of the temporal-spatial characteristics of pollution loading of nitrogen and phosphorus to provide scientific basis f...