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Understanding and quantifying demographic parameters that influence population growth is necessary to effectively maintain population persistence in the presence of recent changes in climate and land use. We used a combination of capture–recapture and harvest information from a 42 yr dataset to create an integrated population model that estimates population abundance, annual survival, and per capita recruitment in Northern Bobwhite (Colinus virginianus). We evaluated the associations of commonly reported population metrics (age ratios from harvests, annual survival, and recruitment) to population growth rate using correlation analysis. We also modeled the effects of population abundance, breeding-season temperature, breeding-season precipitation, fall minimum temperature, and fall precipitation on recruitment. Recruitment averaged 1.55 (range: 0.82–2.21) and was most strongly correlated with population growth (r = 0.78, 95% confidence interval [CI]: 0.63–0.88), followed by annual survival (r = 0.38, 95% CI: 0.09–0.61). We found a weak correlation between fall age ratios and population growth rate (r = 0.11, 95% CI: −0.19 to 0.40). Recruitment exhibited weak, nonlinear, negative density dependence (β1 = −0.13, 95% credible intervals [CRI]: −0.17 to −0.08 and β2 = −0.03, 95% CRI: −0.07 to 0.004). Breeding-season maximum temperature and breeding-season precipitation had a significant, positive effect on recruitment (β3 = 0.15, 95% CRI: 0.11–0.19 and β4 = 0.10, 95% CRI: 0.05–0.16, respectively). Fall minimum temperature and fall precipitation both had negative but uncertain effects on recruitment (β5 = −0.03, 95% CRI: −0.08 to 0.01 and β6 = −0.02, 95% CRI: −0.07 to 0.01, respectively) but less so compared to weather in the breeding season. Our results illustrate that recruitment (1) can be estimated without data on fecundity and chick survival by using integrated population models and (2) is highly correlated with population growth in Northern Bobwhites. We encourage natural resource managers to focus on actions that increase Northern Bobwhite recruitment.

We conducted a comparative study of 2 closely related and sympatric species, Northern Bobwhite (Colinus virginianus) and Scaled Quail (Callipepla squamata), to explore the drivers of interspecific variation in alternative reproductive strategies. Specifically, we used parentage analyses to determine rates of extrapair paternity and intraspecific brood parasitism for each species, and evaluated possible mechanisms for explaining variation in these rates between the 2 species. During 2013–2014, we genotyped hatched (n = 388 for Northern Bobwhite and n = 214 for Scaled Quail) and unhatched (n = 32 for Northern Bobwhite and n = 9 for Scaled Quail) eggshells from 34 Northern Bobwhite and 22 Scaled Quail nests in western Oklahoma, USA. Extrapair paternity occurred in 85% of Northern Bobwhite nests and 9% of Scaled Quail nests. The number of sires for each nest was greater in Northern Bobwhite nests (x = 2.29 ± 0.14 SE sires per nest) than in Scaled Quail nests (x = 1.09 ± 0.06 sires per nest). Intras...

Patterns of nest defense against predators by ground-nesting bird species in the wild are poorly understood, largely because of a historical inability to directly monitor nests. Most nest-defense studies have observed responses elicited from artificial predators or human observers presented to nesting birds, and few have attempted to present these events in the context of predator—prey relationships found in the wild. We hypothesized that predator threat level (e.g., the threat posed to the clutch or to the clutch and the attending adult), parental characteristics, clutch investment, and future reproductive opportunities would influence avian nest-defense decisions. During 1999–2006, we examined predation events (n = 242) from 790 video-monitored Northern Bobwhite (Colinus virginianus) nests. We evaluated parental, predator, daily, and seasonal correlates that potentially contributed to patterns of nest defense by Northern Bobwhites using a model selection approach. The top model showed that nes...

We obtained 1,040 bp of sequence from the mitochondrial DNA (mtDNA) genes cytochrome b (cyt b; 736 bp) and NADH-subunit 2 (ND2; 304 bp) to address phylo- genetic relationships among the four species in the Scaled Quail complex. California Quail (Callipepla californica) and Gambel's Quail (C. gambelii) were sister taxa, whereas the rela- tionships of the Elegant Quail (C. douglasii) and Scaled Quail (C. squamata) were unclear; they might be sister species, or Elegant Quail might be the sister to California plus Gambel's quails. A third, less-likely alternative predicts a contemporaneous origin of Elegant Quail, Scaled Quail, and the ancestor of California and Gambel's quail. The latter phylogenetic hy- pothesis, however, matches Hubbard's (1973) biogeographic model. Irrespective of which biogeographic hypothesis is correct, calibration of mtDNA genetic distances suggests that the speciation events are much older than the late Pleistocene dates given by Hubbard. Cal- ibration of the rate of mtDNA (cyt b, ND2) evolution based on dating of fossil remains of the extinct species Cyrtonyx cooki suggested a rate of 2% per million years. Northern Bobwhite (Colinus virginianus), Mountain Quail (Oreortyx pictus), and Montezuma Quail (Cyrtonyx montezumae) were successively more distantly related to the Scaled Quail complex. Phylo- genetic trees derived from allozymes (Gutierrez et al. 1983) and mtDNA sequences were topologically identical, suggesting that both types of gene trees recover the species tree. Re

The development of functional capacity of skeletal muscle proceeds more rapidly in precocial than in altricial birds and more rapidly in leg than in pectoral muscles. To determine whether protein accumulation and electrolyte differentiation proceed in parallel with functional development, we examined changes in protein (lipid-free dry mass, LFDM), K+ concentrations, and Na+ concentrations in pectoral and leg muscles during postnatal development in altricial European Starlings (Sturnus vulgaris) and precocial Japanese Quail (Coturnix c. japonica) and Northern Bobwhites (Colinus virginianus). Proportion of LFDM in pectoral muscle had a similar pattern of increase in the three species during development, whereas the proportion in leg muscle was slightly higher in bobwhites than in the other two species during the first two weeks. Concentrations of K+ increased and Na+ decreased during development. [K+] exceeded [Na+] for the first time at 4 to 8 days for pectoral muscle and 2 to 8 days for leg muscle in starlings, and at about 5 days for pectoral muscle and 1 to 2 days for leg muscle in quail. Electrolyte concentrations approached adult levels at 13 to 16 days in starlings and 8 to 11 days in both quail. These ages preceded fledging in starlings and first flight in quail by 4 to 6 days. In neonates of each species, the proportion of LFDM was 3 to 5% higher in leg muscle than in pectoral muscle; adult levels of LFDM were achieved 3 to 7 days earlier in leg muscle. Differentiation of the two electrolytes (i.e. crossing of [K+] and [Na+] curves) occurred 2 to 4 days earlier in leg muscle than in pectoral muscle, especially for quail. These results indicate that compositional development of muscle parallels functional development of precocity during postnatal growth. Because the production and maintenance of proteins and the differentiation of electrolytes require metabolic energy expenditure, chemical maturity may compete with growth rate for allocation of energy and nutrients. Received 16 September 1996, accepted 13 May 1997. PROTEINS AND ELECTROLYTES are important chemical bases for the contractile and conductive apparatus of skeletal muscle. Because animals exhibit significant functional development during their postnatal growth, concentrations of these chemicals must change with increasing functional capacity. Previous studies have revealed that protein contents and excitability of skeletal muscles increase dramatically during the early growth period in mammals and birds (Moulton 1923, Dickerson 1960, Hazlewood and Nichols 1969). For instance, in the pectoral muscle of cockerels (domestic fowl), fibrillar and sarcoplasmic proteins increase 3E-mail: ichoi@dragon.yonsei.ac.kr 4Present address: Department of Biology, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Louis, Missouri 63121, USA. more than 2-fold during the first month of growth (Dickerson 1960). Excitability of muscle fibers, indicated by resting membrane potential, increases more than 3-fold in the rat gastrocnemius (Hazlewood and Nichols 1969) and is known to be established by differential partitioning of electrolytes (e.g. potassium and sodium) across the cell membrane (Vernadakis and Woodbury 1964, Hazlewood and Nichols 1969, Park et al. 1981, Ward and Wareham 1985). The age at which concentrations of proteins and electrolytes reach mature levels has been called the point of "chemical maturation" (Moulton 1923). Although previous studies have described ontogenic patterns of the chemical composition of muscle tissue, few data relate variation in the processes of chemical maturation to variation in the rate of development of functional capacity.

ABSmAcr.-We investigated the effects of dietary protein quality on the development and functioning of the immune system in four-week-old Northern Bobwhite (Colinus virginianus) chicks. Chicks were fed isocaloric diets containing 8, 15, or 33% protein over a three-week period. Significant reductions in the rate of body growth were evident in chicks receiving 8 and 15% protein. Development of the bursa of Fabricius and spleen was significantly depressed in the 8% protein group compared to the other two treatments. Lymphocyte yields from dissociated lymphoid organs of chicks fed 8% protein were substantially reduced compared to birds fed higher levels of protein. In vitro lymphoproliferative responses of cultured splenocytes to mitogenic stimulation (concanavalin A, pokeweed mitogen, and Salmonella typhimurium), white-blood-cell counts, and in vivo measures of humoral immunity did not differ among dietary treatments. Cell-mediated immune function, as measured by an in vivo hypersensitivity response to an intradermal injection of a T lymphocyte-dependent mitogen (phytohemagglutinin), was significantly suppressed in the 8% protein group compared to the other two treatments. Several measures of immune-system development and function were significantly correlated with body mass change during the trial. Results indicated that four-week-old Northern Bobwhite chicks fed an 8% protein diet for three weeks may have difficulty expressing a competent immune response to pathogenic challenge in the wild. Received 30 January 1992, accepted 25 November 1992.

We measured values for natural remanent magnetization (NRM) and isother- mal-induced remanent magnetization (IRM) in the head and neck for relatively large samples of eight bird species, and smaller samples of 13 additional species. Significant differences were found in mean NRM values among species; values ranged from 3.090 x 10-12 T (tesla) for the Carolina Wren (Thryothorus ludovicianus) to 38.069 x 10-12 T for the Northern Bobwhite (Colinus virginianus). Mean IRM values ranged from 337.6 x 10-12 T in Chimney Swifts (Chaetura pelagica) to 1,889.1 x 10-12 T in European Starlings (Stutnus vulgaris), with intraspecific variation being notably high. For two European Starlings and a Common Grackle (Quiscalus quiscula), about three-fourths of the IRM was located in the head and one-fourth in the neck; heads of two Northern Bobwhites contained an even greater proportion of the IRM. In general, the direction of the ferromagnetic material varied substantially among individuals within species. No significant differences were found in mean-vector directions among species. Linear regressions of NRM and IRM values on the logs of mean body mass indicate that the intensity of magnetism is related to species size. Insectivores, which also were the smallest species, had lower NRM and IRM values than found for omnivores sampled. Characteristic demagnetization-remagnetization curves suggest that most of the magnetic materials are interacting single-domain or pseudosingle-domain grains of magnetite. Three species may contain some superparamagnetic material. No differences were found between migratory and nonmigratory species with respect to the amount of remanent magnetism, or the extent of intraspecific variability in orientation direction of NRM. Received 24 May 1990, accepted 23 September 1991.

MANY bird studies have shown individual differences in vocalizations within one species. For the most part such spectrographic studies deal with passerine songs, but some work with game birds has been done. Beightol and Samuel (1973) recently completed an analysis of American Woodcock (Philohela minor) vocalizations and showed that individual birds were readily identified by their voice prints. Williams (1971) also found individuality in calls of Bobwhite (Colinus virginianus). If identification of the drums of individual Ruffed Grouse (Bonasa umbellus) were possible then it could be used as a new "tool" for study of longevity and movements of this bird. The drum of the Ruffed Grouse is a nonvocal sound produced by rapid wing strokes (for an exact description of this display, see Hjorth 1970: 225-232). Aubin (1972) examined this nonvocal form of communication and concluded that Ruffed Grouse "answer drumming sounds" of nearby birds, and that the number of wing strokes and the duration of each drum were variable for an individual bird. In our study of the drums of Ruffed Grouse, we were interested particularly to learn if individuals were recognizable by their drumming.

Intraspecific geographic variation in the "hoy" call of female Bobwhite (Colinus virginianus) was studied. Twelve morphometric characters of sonograms of this call for 38 individuals, recorded in the field at the 4 extreme corners of the species' contiguous range in the U.S., were examined by univariate and multivariate statistical techniques. In spite of the absence of striking qualitative differences apparent dialects have been detected for the four populations. Department of Zoology, University of Nebraska, Lincoln, Nebraska 68508. Present address: Department of Biology, Creighton University, Omaha, Nebraska 68178. Accepted 1 June 1976. THE study of individual variation in avian vocalizations attempts to define the limits of variation for single populations (Borror 1959, 1965; Marler and Isaac 1960a, 1960b, 1961; Konishi 1964; Hutchison et al. 1969; Hekenlively 1970; Heinz and Gysel 1970; Emlen 1971a; Williams 1972; Beightol and Samuel 1973), failing to address the dimensionality of the species. Only through detailed analyses of intraspecific variation can one approach the systematics of a species. Many studies of geographic variation in passerine vocalizations (Thielcke 1969; Lemon 1969, 1971; Nottebohm 1969; Shiovitz and Thompson 1970; Bertram 1970; Emlen 197 ib; Harris and Lemon 1972; Baker 1975; Orejuela and Morton 1975) have been reported while only two such studies (Wiley 1971, Van Der Weyden 1973) have been published concerning nonpasserines. All of these studies have dealt with qualitative differences, or at best a few quantitative differences of sonograms, treated univariately, in discussing the species' variability. This study attempts to discern geographic variation in the vocalizations of four populations of the Bobwhite (Colinus virginianus) within its contiguous range in the United States, through multivariate analysis of quantitative morphometric characters of sonograms of one of its calls. The Bobwhite provides an excellent opportunity for study of geographic variation of vocalizations. With the exception of populations in northern Sonora, Mexico, Oregon, Washington, and Idaho, its range is continuous through much of the United States and Mexico. The contiguous U.S. populations have been divided into 3, 4, and 6 subspecies (Aldrich 1946, Ridgway and Friedmann 1946, A.O.U. 1957). Measurements of these subspecies (Aldrich 1946) reveal only slight morphological variation. On the basis of limited samples, Holman (1961) detected a north-south decrease in mean size of skeletal elements to be the only osteological trend for these populations. Ripley (1960) identified a similar trend in the weights of Bobwhites in the east. Aldrich (1946) and Rosene (1969) reported some color variation but suggested that this might be more ecotypic than geographic. The fact remains that several American subspecies of Bobwhite are recognized (A.O.U. 1957), implying a degree of genetic isolation among the contiguous populations. This reduction in gene exchange might be a result of pair formation taking place within coveys, while they are still intact (Stoddard 1931), but unmated males may still pair with females separated from their mates after the coveys disperse. Coupled with the random movement of birds after the breeding season (Stoddard 1931, Agee 1957, Rosene 1969), this would allow for gene exchange between coveys. The low vagility of the Bobwhite (Stoddard 1931, Leopold 1933, Murphy and Bas85 The Auk 95: 85-94. January 1978 This content downloaded from 157.55.39.78 on Mon, 20 Jun 2016 07:25:04 UTC All use subject to http://about.jstor.org/terms 86 RAYMOND B. GOLDSTEIN [Auk, Vol. 95

PAIR bond establishment in birds may be manifested through a variety of behavior patterns. Typically there is a tendency to remain in close proximity to a single individual while avoiding others. Often reproductive and protective behavior are restricted to that individual; aggressive behavior is usually directed only toward other conspecifics. Other behavioral adjustments may be an expression of pair formation as well. A previous study of Ringed Turtle Doves (Streptopelia risoria) (Erickson and Morris 1972) demonstrated that performance levels of two principal behavior patterns, bow-cooing, and nest soliciting, differed according to whether the male was displaying to an unfamiliar female or to a former mate. The functional significance of these behavior patterns is not positively known, but it was suggested that bow-cooing is effective in achieving reproductive isolation, and nest soliciting is important in establishing the pair at the nest site. It was found that much more bow-cooing was exhibited in the presence of unfamiliar females, while slightly more nest soliciting was displayed to former mates. Other investigators have reported such modifications in display and vocalization among mated pairs. Stettner et al. (1966) and Stettner et al. (1971) found more frequent aggression toward nonmates and greater frequency of copulation with mates in Bobwhite Quail (Colinus virginianus). Mundinger (1970) discovered that paired male and female cardueline finches modify their calls to resemble one another. He found changes of this sort even in mixed-species pairs where Pine Siskin (Spinus pinus) males were paired with European Siskin (Carduelis spinus) females. Perhaps most dramatic are the antiphonal duets that develop among pairs of several avian species. Such duets may be either very simple and occasional as occurs in the "hit-tuck" of the White-breasted Nuthatch (Sitta carolinensis) (Kilham 1972) or as elaborate and extended as the flutelike, multiphrased expositions of the African bou-bou shrikes (Thorpe and North 1965). Although it is clear that pair formation may be reflected in modifications of social interaction with both mate and nonmate, as yet few investigators have systematically attempted to trace the development of such behavioral modifications. The present study was designed to follow the divergence in performance when animals are exposed to familiar and unfamiliar animals.

THE Scaled Quail (Callipepla squamata) is known to hybridize with at least two other quails, the Gambel's, Lophortyx gambelii (Bailey, 1928) and the Bob-white, Colinus virginianus (Sennett, 1892). This paper is concerned with the latter cross. In the fall of 1940, Elmer Hanson of Racine, Wisconsin, who bought and sold live wild animals, showed me a crate containing six quail. When asked to identify these birds I said they were Scaled Quail, although the coloring was generally darker and by no means typical. Hanson informed me these birds were hybrids between a Bob-white and a Scaled Quail. The history of Hanson's birds is briefly this. He had held a pair each of Bob-white and Scaled Quail in the same pen awaiting prospective buyers. No such buyers materialized so Hanson was forced to hold the birds into the breeding season; and because space was limited, both pairs were kept in one small pen. Assuming that these distinct species would segregate during mating, no further thought was given to the birds until both females built nests and laid eggs. Hanson then noticed that the male Bob-white courted both hens and drove the male Scaled Quail from them. When the young hatched and were half-grown, the cross between the male Bob-white and female Scaled Quail was detected. The hybrids, six in all, represented a complete hatching of the six eggs laid. All were raised, and when I saw the birds in October of that year they were lively and appeared to be in perfect health.

Descriptions of a portable egg candler, an egg volumeter, and the technique of photographing incubated eggs with transmitted light have been presented elsewhere (Hanson, 1954, Journ. Wildl. Mgt., 18: in press). This report, primarily a continuation of the above report, presents photographs and notes on the developmental stages of three species: the Mallard (Anas platyrhynchos), Wood Duck (Aix sponsa), and Bob-white Quail (Colinus virginianus). These photographs should also be useful in determining the stage of development of eggs of other species whose incubation periods are similar. Photographs