Postjuvenal Molt Research Articles

PRE-MIGRATORY LIFE HISTORY STAGES OF JUVENILE ARCTIC BIRDS: COSTS, CONSTRAINTS, AND TRADE-OFFS

Many young birds on the Arctic tundra are confronted by a challenging task: they must molt their feathers and accumulate fat stores for the autumn migration before climatic conditions deteriorate. Our understanding of the costs and constraints associated with these stages is extremely limited. We investigated post-juvenal molt and premigratory fattening in free-ranging juvenile White-crowned Sparrows (Zonotrichia leucophrys gambelii) on the Arctic tundra. We found evidence for trade-offs between premigratory fat accumulation and molt: heavily molting birds had significantly less fat. Birds increased the rate of fat accumulation as the season progressed, but we found no evidence of a similar increase in rate of molt. Using a controlled captive study to isolate the energetic costs of body feather replacement, we found no difference in fat or size-corrected mass of birds actively growing body feathers as compared to controls. Molting birds, however, consumed 17% more food than controls, suggesting a significant cost of body feather growth. Our results provide evidence of significant costs, constraints, and trade-offs associated with post-juvenal molt and premigratory fat accumulation in young Arctic birds.

Geographic Variation in Color, Measurements, and Molt of the Lesser Goldfinch in North America Does not Support Subspecific Designation

Abstract I examined 963 study skins of Lesser Goldfinches (Carduelis psaltria) from the United States to central Mexico, for color, measurements, molt, and plumage wear. These specimens had been previously assigned to as many as three subspecies. Females did not vary geographically in color. Green-backed, green-eared males predominated in the Pacific coastal United States and northern Mexico. Black-backed, black-eared males predominated in the interior, east of 106° West longitude. This west to east color difference varied clinally, and may be a simple genetic polymorphism, so subspecific distinctions cannot be justified by coloration alone. Measurements of bill, tail, and wing, but not tarsus, varied slightly but significantly from smallest along the Pacific coast to largest in south-central Mexico. Since measurements varied clinally, and overlapped extensively, subspecific separation based on size is not practical. Pacific coastal birds subjected to winter rainfall maxima had a complete postbreeding molt, with a sparse prebreeding body molt only in females, and a postjuvenal molt that replaced significantly more flight feathers in males. Interior birds subjected to summer precipitation maxima had a nearly complete or complete prebreeding molt and a usually less complete postbreeding molt. The postjuvenal and postbreeding molts of interior birds were very similar and did not differ between the sexes. Although these sexual and geographic variations of molt are striking, they may reflect phenotypic plasticity in response to environmental contingencies, rather than genetic differences. These variations in one intergrading population support doubts that the Humphrey-Parkes terminology for molts and plumages can reflect phylogenetic homologies among species.

Timing of Postjuvenal Molt in African (Saxicola torquata axillaris) and European (Saxicola torquata rubicola) Stonechats: Effects of Genetic and Environmental Factors

Data on the timing of postjuvenal body molt of 322 Stonechats (Saxicola torquata) were examined by multifactorial residual maximum-likelihood analysis for effects of external and genetic factors. The Stonechats, which belonged to the European subspecies (S. t. rubicola), the African subspecies (S. t. axillaris), and their F1, and F2 hybrids, were exposed to different photoperiodic conditions. The birds differed conspicuously in the timing and duration of their postjuvenal molt. These differences were significantly related to photo-periodic conditions, genotypic group, and the interaction of these factors. European birds generally molted earlier and faster than African birds, and hybrids showed intermediate patterns. Both subspecies started molt earlier under shorter photoperiods but took longer to complete it. African Stonechats had a weaker response to photoperiod than the European subspecies. In addition, molt timing was negatively related to hatching date, with chicks hatched late in the season molting at a younger age than those hatched earlier. Finally, the two subspecies differed in their molt timing when exposed to short days at an early age. The earlier a European bird was placed under short days, the earlier it molted; the reverse was true in African Stonechats. From a small data base, we estimated heritabilities (h2) through full-sib analyses and offspring-parent regressions. In both subspecies, the timing of molt showed high genetic variation, especially at its onset. Within photoperiodic groups, h2 at molt onset was close to unity but decreased during the course of molt. The two Stonechat subspecies timed their postjuvenal molts in a qualitatively similar manner but showed differences that may reflect differences in the selection pressures of their respective environments.

Variable Expression of Sexually Mosaic Plumage in Female Lesser Kestrels

Estacih Bioldgica de Dofiana, C.S.I.C., Avda. M. Luisa s/n, Pabellh de1 Per%, 41013 Sevilla, Spain, e-mail: Tella@cica.es Key words: plumage coloration; Lesser Kestrel: Falco naumanni. The Lesser Kestrel (Falco naumanni) is sexually di- morphic with respect to plumage coloration (Cramp and Simmons 1980). Adult males have a gray-blue head, rump, tail and upper wing-coverts, unspotted chesnut mantle and scapulars, pink-buff to cream with some dark brown marks on the breast, belly and flanks, and a black subterminal tail band. Yearling (i.e., sec- ond-calendar year) males differ because upper wing coverts are brown with dark bars, showing variable extension of gray and brown in the head and tail. Fe- males are completely brownish, independent of age, with dark bars on the head, back and tail, and stripes on the breast and belly. Nestlings show sexual dimor- phism in the rump, and sometimes in tail color (grayish in males, brownish in females) (Negro and Hiraldo 1991, Tella et al. 1996a). Both sexes have a partial post-juvenal molt (October-May), and a complete post- breeding molt (June-January) in yearling and older birds. Between 1993 and 1995, we captured and color banded 389 female Lesser Kestrels in Los Monegros (NE Spain, Tella et al. 1996b). Most of them had al- ready been banded as nestlings in the previous five years, enabling us to determine their exact age. Looking for plumage variability of these females, we found two of them showing male and female plumage expressed in a mosaic fashion. The first one (OM), a three-year-old female, was caught on 1 May 1993. The left half of its head was like that of a male (gray) and the right side like that of a female (striped brown), and the rest of its plumage was normal. The same female was recaptured on 7 April and 21 June 1994, and it showed no male color patches. However, we trapped OM again on 26 May and 7 June 1995, and again it showed partial male coloration. On this occassion, we photographed the bird to add to our detailed descriptions. The head was bilaterally colored, gray in the left and striped brown in the right. Moreover, the left wing was more similar to that of yearling males than to that of females, with almost unspotted chestnut lesser and middle wing co- verts, and banded greater covers. The tail also had one grayish central rectrix. The rest of the plumage was

Autumnal Migration Departure Schedules in Mountain White-Crowned Sparrows

During seven autumn seasons, Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) departed on migration from a subalpine meadow in September and October. On average, juveniles migrated 3.2 days earlier than adults and there was no difference in schedules of males and females within these two classes. Data from frequently trapped individuals showed that they departed as soon as they became fat. Peaks in departure dates did occur but only once did one occur just before a storm. Mean departure dates among years varied by 14 days in juveniles and eight days in adults. This interannual variation was related to reproductive schedule; departure of the population being delayed by about one day for every two days of delay in nesting (the latter being caused by late-lying snows). Reasons for a decrease in the fledging-migration interlude in juveniles in heavy snow years could have involved an overlapping of postjuvenal molt with premigratory fattening and/or telescoping of molt. Late-born young did not migrate later than those born earlier nor were they leaner at the time of departure. Temporal compensation in adults during heavy snow years was accomplished primarily by overlapping postnuptial molt with parental care and sometimes with premigratory fattening because molt duration did not decrease with season. Premigratory fattening occurred in about nine days in all birds with the average gain per day being 2.3 to 2.6% of initial body mass for the four sex-age groups. Propensity to return to the study area was not related to the body mass at departure in the previous autumn or to its date. It was hypothesized that the attainment of peak fat stores usually served as the proximate stimulus for migration.

The Summer Biology of an Unstable Insular Population of White-Crowned Sparrows in Oregon

We analyzed nest productivity, population size, and temporal aspects of nesting, molting, and premigratory fat deposition in an isolated population of Mountain Whitecrowned Sparrows (Zonotrichia leucophrys oriantha) on the eastern slope of Hart Mountain, Oregon, from 1972 to 1986. This population, nesting from 1,800 to 2,300 m, is near the lower altitudinal limit of oriantha's geographic distribution at the latitude of southern Oregon. Hart Mountain is an isolated massif separated by unsuitable habitat from nearby populations of this bird in the Steens Mountains (80 km) and the Warner Mountains (65 km). The sex ratio of adults was probably 1:1. The number of pairs in a defined sample area diminished from 41 in 1974 to 16 in 1979, and to a smaller but unmeasured number by 1982 to 1986. Losses of eggs and nestlings to predators and to snowstorms were comparatively very large, and productivity (0.99 to 1.72 fledged young per pair per year) was inadequate to replace losses of adults. The year-to-year return ratio (minimum survivorship) of adults was likewise comparatively low, 0.37 in males, 0.31 in females, indicating that mortality was unusually large or that breeding-area fidelity was poor. Analysis of return ratios in relation to population size showed that new oriantha were recruited to the study population from other localities, but not in sufficient numbers to maintain stability. Summer time budgets of oriantha on Hart Mountain were very similar to time budgets of two other populations of these birds in the subalpine zone, suggesting that the Hart Mountain population was not stressed by shortages of time. The postnuptial and postjuvenal molts, in fact, were longer than those of oriantha in a subalpine population. We suggest that we witnessed in 1972 to 1986 the declining phase of repeated cycling of numbers, or of extinction and refounding, that may characterize insular populations or populations at their limits of distribution. On Hart Mountain, heavy losses of progeny to predators and weather were not being compensated by recruitment of adults from nearby sources.

Super-Normal Clutches in Herring Gulls in New England

BAKER, M. C., L. R. MEWALDT, AND R. M. STEWART. 1981. Demography of White-crowned Sparrows (Zonotrichia leucophrys nuttallO. Ecology 62:636-644. BAPTISTA, L. R., AND M. L. MORTON. 1982. Song dialects and mate selection in montane White-crowned Sparrows. Auk 99:537-547. CORTOPASSI, A. J., AND L. R. MEWALDT. 1965. The circumannual distribution of White-crowned Sparrows. Bird-Banding 36:141-169. EMLEN, J. T. 1943. Sex ratios in wintering Gambel Whitecrowned Sparrows. Condor 45:196. HARDY, J. L., D. R. ROBERTS, AND R. C. BANKS. 1965. The composition of a wintering population of Whitecrowned Sparrows in Kern County, California. Condor 67:90-91. KETTERSON, E. D., AND J. R. KING. 1977. Metabolic and behavioral responses to fasting in the White-crowned Sparrow (Zonotrichia leucophrys gambelii). Physiol. Zool. 50:115-129. KETTERSON, E. D., AND V. NOLAN, JR. 1976. Geographic variation and its climatic correlates in the sex ratio of eastern-wintering Dark-eyed Juncos (Junco hyemalis hyemalis). Ecology 57:679-693. KETTERSON, E. D., AND V. NOLAN, JR. 1979. Seasonal, annual, and geographic variation in sex ratio of wintering populations of Dark-eyed Junco (Junco hyemalis). Auk 96:532-536. KETTERSON, E. D., AND V. NOLAN, JR. 1982. The role of migration and winter mortality in the life history of a temperate-zone migrant, the Dark-eyed Junco, as determined from demographic analyses of winter populations. Auk 99:243-259. KING, J. R., D. S. FARNER, AND L. R. MEWALDT. 1965. Seasonal sex and age ratios in populations of the Whitecrowned Sparrows of the race gambelii. Condor 67: 489-504. KING, J. R., AND L. R. MEWALDT. 1981. Variation of body weight in Gambel's White-crowned Sparrows in winter and spring: latitudinal and photoperiodic correlates. Auk 98:752-764. LEWIS, R. A., M. L. MORTON, AND D. S. FARNER. 1968. A second large wintering population of White-crowned Sparrows, Zonotrichia leucophrys gambelii, in Washington. Condor 70:280. MEWALDT, L. R. 1964. Effects of bird removal on a winter population of sparrows. Bird-Banding 35:184-195. MEWALDT, L. R. 1976. Winter philopatry in Whitecrowned Sparrows (Zonotrichia leucophrys). N. Am. Bird Bander 1:13-20. MORTON, M. L., J. L. HORSTMANN, AND C. CAREY. 1973. Body weights and lipids of summering Mountain White-crowned Sparrows in California. Auk 90:8393. MORTON, M. L., J. R. KING, AND D. S. FARNER. 1969. Postnuptial and postjuvenal molt in White-crowned Sparrows in central Alaska. Condor 71:376-385. PARSONS, J., AND L. F. BAPTISTA. 1980. Crown color and dominance in the White-crowned Sparrow. Auk 97: 807-815. STEWART, R. M., L. R. MEWALDT, AND S. KAISER. 1974. Age ratios of coastal and inland fall migrant passerines in central California. Bird-Banding 45:46-57.

Postnuptial and Postjuvenal Molts of Red-Winged Blackbirds in Cass County, North Dakota

Postnuptial and Postjuvenal Molts of Red-Winged Blackbirds in Cass County, North Dakota

Photoperiodic Control of the Molt Cycle in the Chaffinch (Fringilla coelebs)

Abstract The molt cycle in Chaffinches (Fringilla coelebs) has a circannual periodicity under constant photoperiodic conditions (12:12LD, 20:4LD). The molt cycle and/or rate, however, can be modified by artificial alteration of daylength. The time of onset and completion of the post-nuptial molt in Chaffinches under natural conditions is a remote expression of vernal photostimulation. The timing of the molt is initiated at the end of the unifactorial phase of photoperiodic control. The onset of molt is induced after a latent period and its termination after another period, i.e. the molt begins and ends spontaneously. Under natural conditions, daylength immediately before and during the molt does not control either the time of onset or of termination of molt. The additional control system increases the rate of the molt in its early phase under short days, whereas under long days it decreases the rate of molt in its late phase. This system may play an adaptive role in synchronizing the end of the molt among birds that begin molt at different times. The postjuvenal molt begins and finishes spontaneously under control of a program of the individual development of juveniles. Short days increase the rate of molt and initiate earlier onset and completion, whereas long days decrease the rate of the molt and delay the times of onset and completion. Juvenile birds from late broods molt more rapidly than those from early broods. A combination of different programs and photoperiodic control of the molt synchronizes the termination of the molt in juveniles from early and late broods under natural conditions in summer and autumn.

Control of sex differences in the plumage of the house sparrow, Passer domesticus

AbstractIn an experimental study of sexual dimorphism in plumage coloration in the house sparrow, Passer domesticus, skin grafts were exchanged between nestlings on the first to sixth day after hatching. Before fledging, the young birds were moved from the nest to cages and kept for several weeks for observation of the coloration of feathers produced by host and graft skin. The adult feathers that developed on grafted skin at the postjuvenal molt corresponded to those of the donor, regardless of the sex of the host.

Sex Ratio and Sex Determination of Immature Brown-Headed Cowbirds

An unbalanced sex ratio with a predominance of males in the Brown-headed Cowbird (Molothrus ater) has been documented by Friedmann (1929), Mcllhenney (1940), and others. These workers did not investigate sexes in different age groups. Recently Darley (1971) found the sex ratio to be equal in second-year birds. I therefore investigated the sex ratio of more than 7,000 immature (first-year) cowbirds captured in westcentral Kansas. A protracted postjuvenal molt often complicates sexing of immatures by plumage during late summer. Wing length criteria proposed by Wood (1969) were not accurate for this study, so I propose alternative criteria.

The effect of the postjuvenal molt in the house sparrow on infestations of the quill mite, Syringophiloidus minor (Berlese) (Acarina: Syringophilidae).

Syringophiloidus minor (Berlese) was recovered from House Sparrows, Passer domesticus L., ranging in age from nestlings to adults. Of 492 sparrows examined, 402 (82%) were infested. The primaries, major primary coverts, secondaries and rectrices were the most frequently infested feathers. Colonization of the primary coverts and secondaries of the juvenal plumage is selective, with mites favoring those feathers which occupy positions near the end of the molt sequence. Postjuvenal molt alters the frequency of infestation of feathers within a tract and also the frequency of infestation of entire tracts or combinations of tracts. The selective value of the infestation patterns in the juvenal and nuptial plumages and the probable sources of the dispersants which colonize the nuptial feathers during the postjuvenal molt are discussed.

Geographic and Seasonal Variation in the Occurrence of Incompletely Pneumatized Skulls in the House Sparrow

The process of skull ossification or pneumatization, by which most songbirds obtain a double-layered cranium during the first year or so of life, has received detailed documentation for the House Sparrow (Passer domesticus) (Nero 1951; Harrison 1960). House Sparrows commonly achieve the fully double-layered, adult cranium by the age of 6 months, with incomplete pneumatization persisting in occasional individuals for a somewhat longer period (up to 221 days in one sparrow seen by Nero). During each of four seasons in 1968-69, I collected P. domesticus at five localities on an east-west transect running from the eastern edge of the Great Plains at Lawrence, Kansas, into the southern Rocky Mountains at Gunnison, Colorado (table 1). These specimens were preserved as flat skins and cleaned skeletons with entire skulls. I collected only individuals which had completed the postjuvenal molt. This restriction, coupled with the observation that all birds collected during spring and summer were in breeding condition, reasonably assures that individuals taken in spring and summer were in at least their second calendar year of life. The occurrence of a few such individuals with skulls not completely ossified (this condition is hereafter abbreviated as snco, the fully pneumatized condition is termed sco) prompted me to assess the proportions of snco's in each seasonal locality sample. Packard (1967) has studied morphological geographic variation in P. domesticus along essentially the same transect. Chi-square tests of proportional differences in twoway contingency tables provided the statistical foundation for all of the following analyses.

Evaluation of Proximal Primary Feather Criteria for Aging Wild Pheasants

Wild Illinois pheasants (Phasianus colchicus) captured in fall and winter, 1969-70 and 1970-71, and separated into juvenile and adult age-classes on the basis of bursa depths, were used to evaluate proximal (innermost or Number 1) primary measurements as age criteria. The proximal primary shaft diameters (PPSD) of 307 cocks, collected during fall, separated into juvenile and adult age-classes at 3.210 mm (0.1264 inch) with 92 percent reliability. A sample of 46 cocks, collected duxing winter, separated with 98 percent reliability at the same measurement. In a sample of 285 hens captured during fall, the separation point occurred at 2.908 mm ( 0.1145 inch) with 90 percent reliability. However, in a sample of 234 hens taken during winter, separation occurred at 2.858 mm (0.1125 inch) with 92 percent reliability. The reliability of PPSD as separation criteria could not be enhanced by taking into account the lengths of the proximal primaries. Oven-drying of proximal primaries was necessary to obtain repeatable measurements. Mean PPSD of juveniles of both sexes were significantly larger in the fall than in the winter, whereas those of adults showed no signi$icant difference. The fully grown PPSD of juveniles of both sexes, as measured in fall, were positively correlated with their estimated hatching dates. The PPSD of adults were inversely correlated with their estimated dates of molt initiation. Although there was no apparent explanation for seasonal differences in PPSD, the smaller PPSD of juveniles in winter suggested lower fall-to-winter survival rates of late-hatched juveniles (with large proximal primaries), compared with early-hatched juveniles. Dorney and Holzer ( 1957 ) used the diameter of the ninth primary shaft as a criterion for estimating the age of ruffed grouse ( Bonasa umbellus ) cocks in spring. Wishart (1969) extended this technique to game-farm-reared ring-necked pheasants, using the proximal (Number 1) primary because juvenile pheasants, unlike grouse, replace the outer two (Numbers 9 and 10) juvenal primaries during their post-juvenal molt (Wright and Hiatt 1943). The purpose of this paper is to evaluate the application of this technique to wild Illinois pheasants. Evidence will be presented on the possibility of age-specific differences in fall-towinter mortality. We thank W. R. Edwards, C. M. Nixon, Dr. G. C. Sanderson, and Helen C. Schultz 1 A contribution from Illinois Federal Aid Project W-66R, the Illinois Department of Conservation, the U. S. Bureau of Sport Fisheries and Wildlife, and the Illinois Natural History Survey, cooperat-

Postnuptial and Postjuvenal Molt in Rufous-Collared Sparrows in Northwestern Argentina

been proposed to date (Chapman 1940; Koepcke 1963, 1971; Phelps and Phelps 1955; Wetmore 1951). Owing to this diversity the Zonotrichia capensis complex is an especially attractive model for examination of adaptive radiation in various functional attributes. The investigations by Chapman (1940), Miller (1961), Wolf (1969), and Davis (1971) provide the basis for an initial survey of the patterns of molt in populations of Z. capensis extending from Costa Rica to Peru'. To these reports I am now able to add data from Z. capensis in northwestern Argentina. Attention will be confined here mainly to the pattern and tempo of molt. The phasing and regulation of molt cycles as components of the entire annual cycle will be considered in a separate report.

Molt Cycles of Purple Martins (Progne subis)

Interest in the adaptive aspects of avian molt cycles has recently engendered several studies of molt, relying, in part at least, upon a detailed comparative base. Comparative studies of avian molts including detailed comparisons between sexes and among juveniles, first-year birds, and adults of a single passerine species are rare; Foster's (1967) is the only one known to me. The Purple Martin (Progne subis) is a species in which juvenal, first-year, and adult plumages (the latter two strongly sexually dimorphic) can be distinguished (Ridgway 1904; Niles, unpubl.), and is thus an appropriate subject for the examination of intrapopulation variation in molt. This paper describes certain aspects of the postnuptial and postjuvenal molts of Purple Martins, with emphasis on age-related or sexrelated differences in timing and extent of the molts. The molts are also discussed relative

A Breeding Biology Study of the Verdin, Auriparus flaviceps (Sundevall) in Arizona

The breeding biology of the verdin, Auriparus flaviceps (Sundevall), was studied from February 1965 through January 1967 in a Larrea-Franseria-Cercidium association, 9 miles NE of Mesa, Maricopa Co., Arizona. Behavioral data were obtained principally from studying 12 banded nesting pairs. Ninety-three verdins (36 adults, 26 immatures, fledglings that had not completed the postjuvenal molt, and 31 nestlings) were marked. The solitary verdin was resident in the study area and appeared to occupy a large home range. Breeding home ranges of six pairs in 1965 averaged 23.7 acres. Only the area near the nest was defended by both sexes. Vocal activity appeared to be extremely important in pair-formation and in integrating the verdin's activities. Eight different notes were distinguished; functions of these are discussed. Two kinds of nests were constructed: -breeding nests built by the pair and utilized for rearing the young; roosting nests built by either the male, female or lst-year verdins for roosting. Two types of roosting nests were distinguished: small nests built in late summer and larger structures, similar to breeding nests, built in autumn and winter. Roosting nests had less lining material, the entrance was more centered and the nest cup, was not deep compared to the breeding nest. Both roosting and breeding nests were composed of three distinct layers. The verdin entered the roost for the night earlier than most desert birds, and was one of the latest to arise in the morning. In 1965 eggs were found from 6 March to 8 June; in 1966, from 16 March to 29 May. Eggs were laid singly on consecutive days. Mean clutch size for 28 clutches was 3.82 eggs. Modal clutch size was four eggs. Second broods were common. Only the female incubated; the male did not develop an incubation patch. The incubation period ranged from 14 to 17 days in five nests. The mean diurnal attentive period was 11.9 min and the mean inattentive period was 9.6 min. The female incubated throughout the night. During the 1st week of the nestling period, only the female was observed to feed the young. Thereafter, the male fed the nestlings as frequently or more frequently than the female. No evidence of regurgitation feeding was found. The nestling period was 17 to 19 days. Hatching weights of the young ranged from 0.7 to 1.0 g. Fledglings received care for about 18 days; typically the male assumed this task and it was he who usually took the fledglings to the nest to roost. Fledglings were dependent upon their parents for food during the 1st week. Hatching success for 25 breeding nests was 48.8%; fledgling success was 29.1%. In 20 completed clutches, hatching success was 54.5%; fledgling success 32.4%. 1 Present address: Department of Biology, Florida Technological University, Orlando 32816

Postnuptial and Postjuvenal Molt in White-Crowned Sparrows in Central Alaska

Breeding of migratory birds at high latitudes involves problems of allocation of time and energy among the functions of migration, reproduction itself, and molt. Indeed, in some species, notably swallows and flycatchers, the timing system that has evolved defers the postnuptial molt entirely or mainly until after the southward migration (Johnson 1963). In some populations or species, as in Zonotrichia leucophrys gambelii (Farner 1964), these three functions are sharply partitioned temporally through the course of the late spring and

Age Determination of Pheasants by Measurement of Proximal Primaries

A technique is described for separating adult from juvenile ring-necked pheasants (Phasianus colchicus), from measurements of the shaft diameter and total length of the first primary. The pheasant is one of a few Galliformes to molt all ten primaries during their postjuvenal molt (Petrides 1942:323). Most other gallinaceous game birds retain the outer two juvenal primaries and these feathers are commonly used for separating adults from juveniles. The complete molt of primaries in pheasants has apparently caused investigators to abandon the wing and look elsewhere for age separation between adults and immatures. Ideally, an age criterion should be quantitative and have no overlap between ageclasses. Stokes (1957), and Gates (1966) have shown, for example, that age determination from spurs of male pheasants does not meet either of these standards. Not only do spur lengths overlap, but there is overlap in qualitative characteristics as well. The bursal-depth technique (Linduska 1943) has remained the most reliable aging method for pheasants described to date. However, one of the main weaknesses of both the spur and the bursa as aging criteria is that their reliability becomes questionable after midwinter, that is, the length of the spur of This content downloaded from 157.55.39.210 on Sat, 30 Jul 2016 05:19:26 UTC All use subject to http://about.jstor.org/terms AGING PHEASANTS BY PROXIMAL PRIMARY MEASUREMENT * Wishart 715 Table 1. Comparison of post-juvenal primary 1 measurements of male and female ring-necked pheasants sampled at 16-18 weeks in October, and 48-50 weeks in May. DIAMETER OF PRIMARY 1 (MM) LENGTH OF PRIMARY 1 (MM) AGE-SEX CLASS N x SE Range N x SE Range Male (16-18 wks) 109 3.06 ? 0.01 2.76-3.38 108 163.5 ? 0.42 153-175 Male (48-50 wks) 76 3.05 +0.01 2.84-3.29 62 164.1 + 0.56 155-176 Female (16-18 wks) 100 2.79 0.01 2.60-3.03 100 148.7 ? 0.50 138-161 Female (48-50 wks) 100 2.77 + 0.01 2.40-3.00 82 149.0 ? 0.52 139-160 juveniles progressively continues to increase and the depth of the bursa of juveniles continues to decrease as the bird becomes older. The purpose of this study was to investigate the use of proximal primaries as age criteria in pheasants. The proximal primaries were selected because, as post-juvenal feathers, they are completely grown at about 10-11 weeks and are retained for approximately 1 year (Westerskov 1957:2627). Although the proximal post-juvenal primaries are adultiform, their growth is completed by a bird that is approximately one-half adult size (Westerskov 1957:29). Thus, the proximal post-juvenal primaries are unlikely to be as large as the proximal postnuptial primaries which are grown by adults about the same time of year. I am indebted to J. Pelchat, Alberta Fish and Wildlife Branch, for the care and maintenance of the experimental birds. I wish to thank R. Finegan, B. C. Fish and Wildlife Branch, B. Murray and E. Ewaschuk, University of Alberta, and Janis Hall, formerly of the Alberta Fish and Wildlife Branch, for their assistance in taking several thousand wing measurements. I am grateful to F. C. Zwickel, University of Alberta, for his critical reading of the manuscript.

The Nomenclature of Plumages and Molts

IN The Auk of 1959 (76: 1-31) there appeared an article by P.S. Humphrey and K. C. Parkes entitled "An approach to the study of molts and plumages," which will be the subject of this paper. Some readers may not be familiar with Humphrey and Parkes's paper and therefore would welcome a summary of the principal points discussed by these authors. Feeling unhappy with the terminology of molts and plumages as proposed (in 1900) by Dwight, and which has been, to use their words, the foundation of most, if not all, subsequent work, they decided to replace it with an almost completely new nomenclature. In their opinion (p. 14) "there is clearly a need for a semantically 'clean,' independent, uniform, and practical terminology applicable to plumages and molts of all birds," and therefore they endeavored to introduce a nomenclature which might assist in clarifying homologies of molts and plumages. With that aim in mind, they do not spare a single one of the expressions which are in current use, except the term juvenal plumage. They do away with adult, subadult, immature, annual (or perennial) plumage, nuptial plumage, off-season or non-breeding plumage, and so with Dwight's whole system of molt nomenclature, because they believe that molts should be named in terms of the incoming, and not of the replaced, generation of feathers. They introduce the new term basic plumage to designate what we used to call annual or, following Lynes (1930: 38), perennial, plumage. The molts by which this basic plumage, as well as the juvenal plumage, are replaced should henceforth both be called prebasic molts, no longer the annual and the postjuvenal molt, respectively. In birds which have as adults two plumages per cycle, as, for instance, the Scarlet Tanager (Piranga olivacea), the complete molt is, in their