Bird winter-feeding has become a popular backyard activity around the world, particularly in northern regions of Europe and America with cold winters. However, short- long-term ecological consequences such artificial feeding remain inconclusive. In seasonal environments, timing breeding is crucial aspect that can strongly influence reproductive output ultimately fitness. Individual condition at...

in the present study the allelic polymorphisms of gh, ghr and tgfβ3 genes and its association with egg production traits were investigated. blood samples randomly were collected from breeder hens of mazandaran native fowls breeding station and transported to the laboratory in cold chain condition. dna was extracted using modified salting out method and the desired loci were amplified by specifi...

The present investigation was undertaken to compare the histological changes in thyroid gland of female reproductive cycle of Hipposideros lankadiva (kelaart).Thyroid gland showed marked seasonal variation in weight, quantity of colloid and follicular epithelial height, suggesting that the thyroid gland remains inactive during quiescence and winter dormancy and it became active during the time ...

We examined possible mechanisms underlying seasonal stress modulation in Lapland longspurs ( Calcarius lapponicus), a species that breeds and molts (the energetically costly replacement of feathers) in the Alaskan Arctic. Free-living Lapland longspurs show dramatically reduced maximal corticosterone release during molt compared with the breeding season, an effect lost in captive birds. Neither ...

It is well-known that the blood properties change with seasons, and especially many reports in respect to change in water content have been made. For example, Kuroda (1) reported that the water content in blood increases in summer, while it decreases in winter. The fact can be explained by the view of Bazett (2), Sjostrand (3), Yoshimura and others (4) that the circulating blood volume, especia...

armenian gull larus armenicus formerly listed as a subspecies for herring gull larus argentatus and further introduced as a full species in 1980. this species mostly found in caucasus and middle east regions. thair breeding areas are in georgia, armenia, turkey and iran. meyghan wetland is an important wintering area for a number of migratory species especially for common crane grus grus, furth...

Seasonal declines in avian clutch size are well documented, but seasonal variation in other reproductive parameters has received less attention. For example, the probability of complete brood mortality typically explains much of the variation in reproductive success and often varies seasonally, but we know little about the underlying cause of that variation. This oversight is surprising given t...

The breeding of yaks is highly seasonal, there are many crucial proteins involved in the reproduction control program, especially in follicular development. In order to isolate differential proteins between mature and immature follicular fluid (FF) of yak, the FF from yak follicles with different sizes were sampled respectively, and two-dimensional gel electrophoresis (2-DE) of the proteins was...