Paul A. Johnsgard

Hybridization in the Anatidae and Its Taxonomic Implications

Without doubt, waterfowl of the family Anatidae have provided the greatest number and variety of bird hybrids originating from both natural and captive conditions. The recent compilation by Gray (1958) has listed approximately 400 interspecies hybrid combinations in this group, which are far more than have occurred in any other single bird family. Such a remarkable propensity for hybridization in this group provides a great many possibilities for studying the genetics of speciation and the genetics of plumage and behavior, and it also provides a valuable tool for judging species relationships. It may generally be said that the more closely two species are related the more readily these species will hybridize and the more likely they are to produce fertile offspring. In waterfowl, chromosomal imcompatibility and sterility factors are thought to be infrequent, a circumstance which would favor the large number of hybrids encountered in this group. In addition to this, however, it can probably be safely concluded that the Anatidae are extremely close-knit in an evolutionary sense, for their behavior, anatomy, and other characteristics all indicate a monophyletic origin. It was for these reasons that Delacour and Mayr (194.5)) in their revision of the group, sensibly broadened the species, generic, and subfamilial categories, and in so doing greatly clarified natural relationships. Gray’s compilation, although it provides an incomparable source of hybrid records, does not attempt to synthesize these data into any kind of biologically meaningful pattern. For the past several years I have independently been collecting records and information on waterfowl hybrids for the purpose of obtaining additional evidence for species relationships and in order better to understand problems of isolating mechanisms under natural conditions. With the publication of Gray’s bibliography, little purpose would be served by presenting my compilation in toto, since the two lists are practically identical. However, I believe that condensed graphic summaries, arranged by natural subgroups (tribes) rather than alphabetically as done by Gray, have sufficient value and interest to be presented here.

Sympatry Changes and Hybridization Incidence in Mallards and Black Ducks

ASTRACT: Changes in general fall and winter distributions of Mallards and Black Ducks over the past century have resulted in markedly increased sympatric contact during pair formation between these two forms, and have been responsible for increased opportunities for hybridization. Bureau of Sport Fisheries and Wildlife records of hybrids from 34 states indicate a minimal current hybridization rate that is about 4% of the frequency expected on the basis of mating according to mathematical probabilities of chance contact. Thus, hybridization is most frequent where both forms are almost equally abundant, indicating that no reinforcement of differences reducing hybridization in the primary zone of contact is detectable. The primary zone of sympatry has moved eastward approximately 300 miles during the past half century and will almost certainly continue to do so. Owing to its much smaller gene pool, the Black Duck is vulnerable to eventual swamping through hybridization and introgression, although the present hybridization rate is sufficiently low as to make this unlikely in the foreseeable future.

Evolutionary Relationships among the North American Mallards

THIS study is the report of an attempt to understand the evolutionary relationships existing within a group of mallardlike ducks native to North America. The group includes the Common Mallard, Anas platyrhynchos platyrhynchos L.; the Black Duck, Anas rubripes Brewster; the Florida Duck, Anas fulvigula fulvigula Ridgway; the Mottled Duck, Anas fulvigitla niiaculosa Sennett; the Mexican Duck, Anas diazi diazi Ridgway; and the New Mexican duck, Anas diazi novimexicana Huber. All but one of these (the Common Mallard) are restricted to North America, and all these American forms possess a sexually nondimorphic plumage. In all other respects they are extremely similar to the Common Mallard, and a study of their relationships to this form was believed possibly to provide an instructive example of speciation.

Variability in the Electrophoretic Patterns of Avian Serum Proteins

It has been known for more than 50 years that particular proteins characterize every species of plant and animal and that phylogenetic relationships are reflected in protein structure. The first application of this fact to taxonomic studies was by Nuttall ( 1901; 1904) who used the precipitin reaction of immune sera to test degrees of relationship in over 500 species of animals. With refinements in technique have come many more serological studies and the results have justified the statement by Landsteiner (1945) that “chemical differences parallel the variation in structure” and hence are useful in classification. The literattrre on serology is extensive but it has been summarized in the book by Landsteiner ( 1945) and the reviews by Boyden ( 1942 ; 1953). Some of the more recent papers are cited by Stallcup (1954), and Pauly and Wolfe (1957). The development of other methods for protein characterization has suggested that these too might be applied to systematics. Soon after Tiselius (1937) described his apparatus for the electrophoretic separation of colloidal mixtures Landsteiner, Longsworth, and van der Scheer (1938) used it to compare the egg albumins and hemoglobins of five species of birds. Within the next few years there followed the studies by Moore (1945)) Deutsch and Goodloe (1945)) and Deutsch and McShan (1949). These authors investigated the plasma proteins of several species of reptiles, amphibians, fish, birds, mammals, and some invertebrates. They showed that electrophoresis could detect the species specific qualities of proteins and that similarity in proteins paralleled evolutionary relationships. With the development of filter paper electrophoresis the procedure has been simplified and the study of Dessauer and Fox (1956) on the plasma proteins of more than 100 species and subspecies of reptiles and amphibians has been the most extensive to date. Others who have used paper electrophoresis include Zweig and Crenshaw (1957) who found specific characters in the serum proteins of turtles of the genus Pseudemys, and Starr and Fosberg (1958) who published the serum protein patterns of several species of sharks. Woods et al. (1958) used starch gel electrophoresis in a study of the sera of 19 species of invertebrates. The egg white proteins of birds have also been shown to be species specific and to produce excellent electrophoretic profiles. The papers by Bain and Deutsch (1947) and McCabe and Deutsch (1952) are the principal ones to date. The latter reported on 37 species of birds and concluded that the method was applicable to taxonomic problems. Sibley has used paper electrophoresis in a study of the egg white proteins of more than 300 species and has found the conclusions of McCabe and Deutsch fully justified. In 1956, when the senior author began the study described here, the purpose was to determine the uses and limitations of paper electrophoresis in avian taxonomy. Blood serum, rather than egg white, was chosen because of the relatively greater ease of obtaining material. The egg white studies mentioned above were initiated after the work reported here had been completed.

An Electrophoretic Study of Egg-White Proteins in Twenty-Three Breeds of the Domestic Fowl

Fresh albumen samples from a total of 244 eggs from 23 breeds of Domestic Fowl (Gallus gallus) were analyzed electrophoretically. These breeds include the wild-type Red Jungle Fowl, as well as a wide variety of bantam, laying, and exhibition breeds which provide a large amount of morphological and physiological diversity. No variation in the egg-white proteins among these breeds could be detected that was greater than normal sampling and measuring errors inherent in the technique. It is concluded that the structure of the egg-white proteins is phylogenetically conservative.

Behavior of the Australian Musk Duck and Blue- Billed Duck

THE stiff-tailed ducks include a group of nine species currently placed in four genera (Delacour, 1959), of which only two (Oxyura and Biziura) possess the elongated and stiffened rectrices for which the group is named. Biziura is monotypic and consists of the Australian Musk Duck (B. lobata), but Oxyura includes six species which are widely distributed on all continents and is represented in Australia by the Blue-billed Duck (0. australis). Intrageneric relationships and species limits in Oxyura are still somewhat uncertain (cf. Delacour and Mayr, 1945, with Delacour, 1959), due to considerable external uniformity among most species and limited comparative information. Because of these taxonomic uncertainties and the fact that the stiff-tailed ducks tend to have highly varied and elaborate displays, a comparative study of their behavior patterns has been undertaken in hopes of better interpreting relationships in the group. As a first step in that study, the two Australian representatives were investigated in July and August of 1964, and the present paper summarizes my behavioral observations on these species. Some additional observations on the general behavior, vocalizations, and abundance of these and other species are published elsewhere (Johnsgard, 1965).

COMPARATIVE BEHAVIOR AND RELATIONSHIPS OF THE EIDERS

In my earlier paper several behavior patterns of the eiders were either unknown to me or were uncertain, and only general behavioral features of the sea ducks were discussed. Since that time I have obtained behavioral observations on all of the species of eiders. I have been able to make extended observations on captive specimens of the European race of the Common Eider (Somateria mollissimna mollissima), the King Eider (S. spectabilis), and the Steller Eider (Polysticta stelleri) at the Wildfowl Trust, and recently I observed the sexual behavior patterns of wild Spectacled Eiders (Somateria fischeri) near Igiak Bay, Alaska. These latter observations have provided important additional evidence relating to my earlier views on the relationships of the eiders and make it possible to conclude with greater certainty behavioral homologies and probable isolating mechanisms in the eiders and their nearest relatives. The nomenclature used in this paper follows that of Delacour (1959). Previous behavioral studies on the eiders have been relatively few. Hoogerheide (1950) described the behavior of the European race of the Common Eider in detail, and

A Summary of Intergeneric New World Quail Hybrids, and a New Intergeneric Hybrid Combination

The exceedingly close affinities of the quail genera Colinus, Callipepla, and Lophortyx have been recognized for some time and have recently been emphasized by additional morphological (Holman 1961; Hudson et al. 1966), biochemical (Sibley 1960), and pterylographic (Ohmart 1967) evidence. Indeed, Holman has suggested that these three taxa might best be regarded as subgenera. Phillips et al. (1964) pragmatically merged Lophortyx with Callipepla; and Delacour (1961-1962) synonymized not only Lophortyx, but also Oreortyx and Philortyx, with Callipepla, yet retained Colinus as a separate genus. Although Ohmart (1967) questioned the validity of generically separating Lophortyx and Callipepla, he suggested that any new taxonomic reorganization should also include consideration of such related genera as Colinus. One useful source of evidence for judging possible generic distinction is the occurrence of both naturally occurring and artificially obtained hybrids, and their relative fertility. Thus, before advocating any taxonomic changes among the New World quail genera, a review of recorded intergeneric hybrids would seem to be in order.

Lewis-and-Clark Bicentennial Effusia

The process of unifying biogeography has had its many champions. Originally, in pre-evolutionary Europe, biogeography was unified by the common aim of uncovering the centre of origin, a concept derived from biblical texts. Organisms either were created in the places they were found or they moved there from elsewhere (Buffon, 1766; Sclater, 1858). Whether or not the organisms evolved was not an issue in biogeography. Organisms had a centre of origin (either by creation or evolution) from which they moved, thus forming the strange distribution patterns both in living and fossil species. The advent of Darwinian evolutionary theory, a process (natural selection) proposed to explain biogeographical distribution, was seen to be a unifying theme. Organisms had one centre of origin. Ernst Haeckel, who was deeply influenced by Darwin’s work, proposed a centre of origin for mankind. At first he believed it was the lost island of Lemuria, sunk off the coast of Pakistan. In a later revision he moved it to present day Afghanistan