Molt Of Primary Feathers Research Articles

Annual cycles of migratory fattening, reproduction and moult in European quail (Coturnix coturnix)

Experimental studies of the physiological mechanisms underlying avian migration have concentrated on small passerines. The present study is concerned with the regulation of migratory fat deposition in a galliform. the European quail (Coturnix coturnix). The increased mass associated with migration was due exclusively to the deposition of fat whereas the increased body mass of laying females was due to increases in lean tissue and water as well as fat. Annual cycles of body mass, moult, gonadal size and plasma luteinizing hormone were measured every other week in captive males and females held outdoors under natural daylengths and temperatures in Bristol, UK (51° 27′ N). Males and females showed two peaks of fat deposition each year which occurred at the migratory passage times reported in wild birds. Luteinizing hormone levels and gonadal size increased in parallel with vernal fat deposition, and remained high until late summer. The pattern of primary feather moult in the intact birds was similar to that of wild quail, with moult following gonadal regression and being suspended during autumnal fattening. Castration of European quail did not inhibit the expression of migratory fattening, as it does In certain passerines. In fact, castrates displayed fattening cycles that were more clearly defined and of greater amplitude than those in the intact males. The annual cycle of European quail differs from that of other well‐studied passerine migrants such as Zonotrichia sparrows, and this is most likely associated with differences in breeding ecology. In addition, the ability of quail to express vernal fattening independently of the presence of the gonads suggests that taxonomic differences between migratory species are also apparent in the physiological mechanisms of migratory fattening.

Sex-Specific Differences in Molt Strategy in Relation to Breeding in the Wandering Albatross

The extent of molt of primary feathers was studied in relation to the status and to the duration of the interval between breeding attempts in the Wandering Albatross (Diomedea exulans). The replacement of primaries lasts for more than one season, birds showing a typical wave molt with one to three foci occurring on a wing. Molt never occurs on the breeding grounds. In breeding as in nonbreeding individuals, males invariably renew more feathers than females. Breeding males and females renewed each year an average of 8.3 and 7.3 primaries per wing, respectively. The extent of primary molt of breeders was directly related to the duration of the interbreeding period in females but not in males. Males and females breeding for the first time had fewer new feathers than did experienced birds. When they visited the nesting colonies, immature birds had fewer new feathers than did breeding birds of the same sex. In immature birds, the extent of molt was related to the body condition (mass) of males but not of females. The extent of molt was inversely related to mass gain from one season to the next in nonbreeding males. These results suggest that molting in the Wandering Albatross is probably an important constraint that could compete with breeding, particularly in females. Possible reasons for sex-specific differences in molt extent are discussed.

Body Morphometrics and Molt of Bonaparte's Gulls in the Quoddy Region, New Brunswick, Canada

In the Quoddy region of New Brunswick, Canada, the postnuptial molt and feather renewal of Bonaparte's Gulls lasted about 14 weeks with the primary feather molt of the second-year birds being more advanced than that of the adults by 20 to 30 days or 2 to 3 primary feathers. Males were larger than females by body weight, and body, culmen, and tarsal lengths. There was a general trend for migrants passing through the Quoddy region during July and August to be larger in size than during October and November. Based on culmen and tarsal lengths measured on museum specimens collected from different geographical regions of the breeding range, there was a general trend for decrease in body size from east to west, which suggests that the first migrants through the Quoddy region represented populations from the east followed later by western populations.

An analysis of weight changes in the Mute SwanCygnus olor

The weights of Mute Swans contain useful information on individuals' prospects for survival and breeding but to interpret them one needs to know what 'typical' weights would be. This paper uses multiple linear regression to predict such 'typical' weights: 1968 zveighings of 957 Mute Swans, from south Staffordshire, England, are analysed with respect to sex, age, moultstage, month of capture and breeding status. Because of marked sexual dimorphism, knowing a swan's sex is fundamental to interpreting its weight; age from hatching and stage of primary feather growth affect cygnets' weights near fledging; weights of young swans change with age during their first years of life; primary feather moult significantly depresses the weights of first year males but not, in this study area, of older males or females; monthly, seasonal changes are generally small; breeding adults are significantly heavier. The results and their biological implications agree well with other, less comprehensive, analyses. The method desc...

Primary Feather Molt and Serum Luteinizing Hormone Concentration in Chukar Partridge (Alectoris chukar) During a Photoperiodically Induced Molt With or Without Fasting

In two experiments, 135 adult chukar partridge of two genetic lines, one selected for high egg production and a random-bred control line, were induced to molt by reducing photoperiod from 16 hr light/day to 8 hr light/day on Day 0. In Experiment 1, feed was removed from approximately half the birds on Day 0 and returned on Day 7, Birds in Experiment 2 were not fasted. Photoperiod was increased to 16 hr light/day on Day 56. Primary feather molt scores, body weights, and, in Experiment 2, serum luteinizing hormone (LH) levels were monitored weekly through Day 85.Prior to the short day period, birds selected for high egg production and females had lower molt scores than controls or males, respectively. Fasting had no effect on molt scores, egg production, or body weights (except during the fasting period). Selected-line birds returned to lay approximately 3 days earlier and laid approximately 16 more eggs during the second production period than controls.Six days before photoperiod was reduced, immunoreactive serum LH levels were 5 to 8 ng/ml; they declined during short days to about 4 ng/ml. Within 8 days after relighting, LH levels increased to approximately 33 ng/ml in males and 18 ng/ml in females. Luteinizing hormone levels remained elevated in males throughout the subsequent 4 weeks but declined in females as egg production resumed.

BIOLOGY OF THE GREENSHANK IN SOUTHERN AFRICA

Summary TREE, A. J. 1979. Biology of the Greenshank in southern Africa. Ostrich 50:240-251. The Greenshank Tringa nebularia is a widespread visitor to southern Africa but is only normally common at favoured coastal sites. First migrants arrive at the end of July and the last birds leave in early May. Small numbers overwinter. Birds in the interior are forced to move coastward or southwestward once the summer rains set in and rapidly inundate suitable habitat. Peak numbers occur in January at Port Alfred, a coastal site. Greatest concentrations of Greenshanks occur on eutrophic bodies of water in the interior while at coastal localities the density of prawns appears to determine Greenshank numbers. It is normally a diurnal feeder but will feed at night in tidal areas when fattening up for return migration. It roosts communally standing in shallow water. Birds can be aged on plumage condition and primary feather moult. Birds have a lean mass of about 170 g while the potential migratory range on fat deposits accumulated is calculated to carry birds from the Cape coast to the East African lakes and thence to the Mediterranean or Caspian Seas. There is a considerable disparity in mass between inland and coastal localities. One banding recovery in Cyprus is noted; a low retrap rate is gradually being improved by colour ringing.

Primary Feather Molt of Adult Mourning Doves in North and South Carolina

Examination of 8,141 adult mourning doves (Zenaida macroura) in North and South Carolina revealed that substantial numbers complete primary feather molt in September. Adult mourning doves shed primaries at the rate of 1 per 14 days. No difference was found in this rate between sexes or among years, 1969-74. The initiation of molt differed from year to year, and female molt always preceded male molt. Available data show that southern doves complete primary molt a month earlier than northern doves. Therefore, age based on primary molt can be biased upward if all molt-complete wings from southern hunting samples are considered immature. J. WILDL. MANAGE. 43(1):202-207 Indices of mourning dove reproductive success can be derived from age ratios obtained through hunter bag surveys. This information combined with indices of breeding population size allows biologists to evaluate trends in both population size and annual production. Biologists segregate immature and adult doves by wing plumage characteristics. After the completion of annual wing molt, such identification becomes impossible. Currently, molt-complete doves are considered to be immatures in September, because in a Missouri study of adult mourning dove primary feather molt, 97.5% of the adults had not completed primary molt until October (Sadler et al. 1970). The number of molt-complete doves averaged 6.2% in the Eastern Management Unit Dove Wing Collection Survey for the 1967-70 September hunting seasons (J. L. Rous, pers. comm.). If the Missouri findings do not apply to the entire range of the mourning dove, the possibility of age ratio error exists. This study was undertaken to document adult primary molt in North and South Carolina, examine variability in rate of molt among years and between sexes, predict the earliest dates at which adults complete primary molt, and compare this study's findings with the earlier Missouri study (Sadler et al. 1970). We express our gratitude to R. A. Coon, D. H. Johnson, and R. E. Tomlinson, U.S. Fish and Wildlife Service, and K. C. Sadler, Missouri Department of Conservation, for many helpful suggestions regarding data analysis and manuscript preparation.

Delayed Molt of Primary Feathers of Mourning Doves during Winter

Delayed Molt of Primary Feathers of Mourning Doves during Winter

THE MOULT OF THE WHITE‐BACKED AND RÜPPELL'S GRIFFON VULTURES GYPS AFRICANUS AND G. RUEPPELLII

SummaryMoult is continuous throughout the life of the White‐backed Vulture and Rüppell's Griffon Vulture. Primary feather moult starts about 10 months after the bird leaves the nest, and the first feather to be shed is the innermost primary. From this position primary moult proceeds in an orderly sequence outwards towards the tip of the wing. Secondary feather replacement does not occur by the progression of moult waves, but by the irregular growth of feathers. It probably takes about 3 years of moult activity to complete the first feather replacement. Subsequent feather replacements occur by a slow but continuous process of feather replacement. Birds in adult plumage do show variations in the speed of moult, but this could not be related to breeding or body condition.

Effects of thiouracil on testicular regression, thymus weights, and molt in pheasants

Administration of 0.1% (by weight) thiouracil in the diet of adult male pheasants ( Phasianus colchicus) from the peak to the end of their breeding season (2–3 months) caused the growth of large goiters, but had no observable effect on normal regression of their testes. No significant differences ( P > .05) occurred in body, testis, adrenal, or anterior pituitary weights nor in total gonadotropin content of the pituitaries between thiouracil-treated and control birds. Thymus weights differed significantly ( P < .02) between treated and control groups, being smaller for the former. Thiouracil had no effect on the progression of the postnuptial molt of primary feathers.

Eye Lens Weights as Indicators of Age in Rock Doves

Variation in eye lens weights of 45 known-age rock doves (Columba livia) and 92 rock doves collected over a 15-month period indicated that lens weights could be used to estimate age only in nestlings and early juveniles. Little, if any, increase in lens weight was apparent after the first 112 days. While numerous workers have shown eye lens weights to be reliable indicators of age in several species of wild mammals, investigators applying the technique to birds have reported only limited success due primarily to early attainment of adult size. Friend (1967) presented a comprehen- sive review of this literature. Labisky et al. (1969:272) reported that lens weights could not be used satisfactorily to separate juve- nile ring-necked pheasants (Phasianus col- chicus) into monthly age-classes, juvenile cocks older than 5 months or juvenile hens older than 3 months from adults, or adults into yearly age-classes. Rock doves were trapped in Boston, Mas- sachusetts, as part of a survey of their protozoan, nematode, and ectoparasites. Be- cause examination of the bursa and pattern of primary feather molt provided only rela- tive age, eyes were collected to determine if lens weights could be used to separate juvenile doves into monthly age-classes, and adults into yearly age-classes. The author wishes to thank Barbara

The Effect of Progesterone on Egg Formation in Sixteen-Week Old Pullets

ABSTRACT PROGESTERONE, a steroid hormone found in the blood of hens and roosters but not in capons (Fraps et al., 1949), has been shown to affect the ovary differently, depending on dosage, interval of treatment and method of administration. Shaffner (1955) reported that hens injected with progesterone ceased egg production immediately after treatment and showed signs of heavy molt from ten to fourteen days later. He indicated that most of the birds had resumed egg production eight weeks following the treatment. Egg weight and body weight were not influenced by the treatments. Different methods of administering progesterone to yearling hens were compared by Adams (1955) who found that whether fed, implanted, or injected, progesterone caused a decrease in egg production and an increase in the rate of primary wing feather molt. Estrogen primed rabbits need 200 mg. of progesterone orally to equal uterine proliferation of rabbits injected subcutaneously with 0.25 to . . .