Interactive effects of body mass changes and species‐specific morphology on flight behavior of chick‐rearing Antarctic fulmarine petrels under diurnal wind patterns

For procellariiform seabirds, wind and morphology are crucial determinants of flight costs and flight speeds. During chick‐rearing, parental seabirds commute frequently to provision their chicks, and their body mass typically changes between outbound and return legs. In Antarctica, the characteristic diurnal katabatic winds, which blow stronger in the mornings, form a natural experimental setup to investigate flight behaviors of commuting seabirds in response to wind conditions. We GPS‐tracked three closely related species of sympatrically breeding Antarctic fulmarine petrels, which differ in wing loading and aspect ratio, and investigated their flight behavior in response to wind and changes in body mass. Such information is critical for understanding how species may respond to climate change. All three species reached higher ground speeds (i.e., the speed over ground) under stronger tailwinds, especially on return legs from foraging. Ground speeds decreased under stronger headwinds. Antarctic petrels (Thalassoica antarctica; intermediate body mass, highest wing loading, and aspect ratio) responded stronger to changes in wind speed and direction than cape petrels (Daption capense; lowest body mass, wing loading, and aspect ratio) or southern fulmars (Fulmarus glacialoides; highest body mass, intermediate wing loading, and aspect ratio). Birds did not adjust their flight direction in relation to wind direction nor the maximum distance from their nests when encountering headwinds on outbound commutes. However, birds appeared to adjust the timing of commutes to benefit from strong katabatic winds as tailwinds on outbound legs and avoid strong katabatic winds as headwinds on return legs. Despite these adaptations to the predictable diurnal wind conditions, birds frequently encountered unfavorably strong headwinds, possibly as a result of weather systems disrupting the katabatics. How the predicted decrease in Antarctic near‐coastal wind speeds over the remainder of the century will affect flight costs and breeding success and ultimately population trajectories remains to be seen.     

Dose response kinetics of serum vitellogenin, liver DNA, RNA, protein and lipid after induction by estradiol-17 beta in male flounders (Platichthys flesus L.).

1. Male flounders receiving 100 micrograms estradiol each second day were fully induced to vitellogenin synthesis within 11 days, while fishes given 5 micrograms doses continued to accumulate vitellogenin in the serum at a progressive rate through 17 days. 2. Liver DNA per unit fish remained constant, while RNA per unit fish in flounders given 100 and 5 micrograms doses attained values 80 and 25% respectively, above the values found in control animals. 3. Liver RNA per unit DNA increased at maximal rate within 6 days in fishes receiving 100 micrograms doses. RNA synthesis continued at a progressive rate through 17 days in fishes given 5 micrograms doses of estradiol. 4. Liver protein per unit DNA elevated at a plateau 60% above control within 6 days with 100 micrograms doses. Doses of 5 micrograms had only little effect on liver protein. 5. Estradiol had a lipogenic effect on the liver. Cellular lipid rose 120 and 60% above control after treatment with 100 and 5 micrograms respectively. 6. Liver dry weight per unit DNA increased 60 and 55% above control with 100 and 5 micrograms doses respectively. Cellular hypertrophy in fishes receiving the smaller dose was primarily associated with an increase in lipid concentration, while protein and lipid contributed almost equally to cellular growth in fishes receiving the high dose.     

Protein and energy self-selection of turkey hens. Serum prolactin and luteinizing hormone concentrations.

1. The incidence of broodiness was four times as high among turkey hens fed a complete control diet than among hens allowed to self-select their diet from two different feed sources, one being relatively high in protein and the other relatively high in energy (i.e. split-diet). 2. Among non-broody birds, hens fed the split-diet had a significantly lower serum prolactin concentration in the third month of production as compared to control hens. 3. Hens in their second season of egg production had significantly lower serum luteinizing hormone concentrations during the latter stages of egg production than did first season hens.     

Epidermal growth factor (EGF) stimulation of ATP citrate lyase activity in isolated rat hepatocytes is age dependent.

1. The effect of epidermal growth factor (EGF) on ATP citrate lyase activity was determined in freshly isolated hepatocytes from rats of different ages as a function of incubation time, EGF concentration and hepatocyte density. 2. The activity of this enzyme was responsive to both dose and time of incubation of EGF with a two-fold increase in ATP citrate lyase activity and a half-maximal effect between 10(-12) and 10(-11) M. 3. EGF effects were detectable by 5 min. 4. The age of the rats had a strong effect on the magnitude of the EGF effect with ATP citrate lyase activity in younger (8 weeks) rats being more responsive than in older (14 weeks) rats.