Birds In Good Condition Research Articles

When do helpers help? Food availability and helping in the moorhen, Gallinula chloropus

The importance of food availability as a constraint upon cooperative behaviour was examined by providing supplementary food on some breeding territories of a population of moorhens (Gallinula chloropus). First brood juveniles on territories provided with food were more likely to feed their younger second brood siblings. Supplementary feeding improved the physical condition of juveniles above that of unfed conspecifics, and birds in better condition were more likely to be helpers. Helpers on fed territories also provided more food to siblings than did their counterparts on unfed territories, enabling parent birds to reduce their work rates. Results are discussed in relation to the benefits which may accrue to helpers and the energetic costs of cooperation which may act as proximate constraints upon potential helpers.

Selection of Heather Age and Chemical Composition by Red Grouse in Relation to Physiological State, Season and Time of Day

When given a choice of heather of the same age but different chemical composition, captive Red Grouse in poor body condition preferred to eat plants containing more nitrogen and phosphorus, but not calcium, whereas birds in good condition showed no such preference. When given a choice of different ages of heather at the same height at different times of year, grouse in poor condition ate more of the young, more nutritious, heather than did those in good condition, at all seasons; all birds preferred young heather in spring. This confirms the importance of physiological state of the bird, and chemical composition of the heather, in determining choice. Selection for N and P (not Ca) from heather by wild Red Grouse were correlated negatively with mean weights of heather particles eaten and with total weights of crop contents (which were assumed to reflect feeding rates). Grouse thus tended to be more selective for N and P when they ate smaller particles and fed slowly. In autumn and winter, wild grouse selected more for N and P, and less for Ca, in the morning and afternoon than in the evening, but there was no difference with time of day in spring. In spring, selection for N and P were lower in the morning and afternoon, and greater in the evening, than in autumn and winter. Seasonal and diurnal variation in selection for nutrients was associated with variation in feeding rates (as indicated by weights of crop contents) and in weights of heather particles eaten.

Variability of Seasonal Scratch Grain Consumption Observed in Leghorns

In a previous report of investigations concerning consumption of scratch grain in the egg laying contests in New Jersey,22R. R. Hannas, An Analysis and Interpretation of Heavy Grain Feeding. Poultry Science, V. III, No. 6. Ralston R. Hannas has expressed the opinion that experience in contest feeding indicates that in general practice, even with heavy feeding of grain in the early fall, sufficient amounts have not been fed to keep the birds in good condition so they will hold up in production during the summer. Evidence presented in this paper throws additional light upon the importance of heavy grain feeding during the four winter months, November–February, in comparison with the spring and summer-fall periods.The following table summarizes the data for the three seasons investigated : November–FebruaryMarch–JuneJuly–OctoberWinterSpringSummer-FallMean productionEggs per bird weekly2.204.573.06Eggs per 100 birds daily31.4365.2843.71Mean Scratch Grain ConsumptionPounds per bird weekly.80.70.46Pounds per 100 birds daily11.4310.006.57