Observations on the Great Grebe

Abstract

many ways parallel those of the Western Grebe (Aechmophorus occidentalis), and for many years the two were considered congeneric. Wetmore and Parkes (1954) showed that major should not be included in the genus Aechmophorus, a view which is strongly supported by behavioral evidence reported here and by the structure of the cervical and thoracic vertebrae to be reported on in detail elsewhere. Whether or not major is correctly placed in the genus Podiceps is a question on which I prefer to withhold judgment until more detailed anatomical studies can be made. The adaptations for life as a fish-eating inhabitant of large lakes include the long, narrow body, the long neck, the long, pointed bill, and the large feet. The narrow body is most evident when the bird is in the hand; and in this, the Great Grebe differs from the broader-bodied Red-necked Grebe (Podiceps grisegena) much as the Common Merganser (Mergus merganser) differs from the Common Goldeneye (Bucephala clangula). The long neck and spear-like bill must be efficient tools for the capture of fish. The posture of the neck in certain displays (the S-neck Posture, fig. lh) suggests that there may be a trigger mechanism like that in the necks of herons, anhingas, and the Western Grebe. However, as has been mentioned, the structure of the vertebrae show that such a mechanism, if present in the Great Grebe, must be considerably different from that in the Western Grebe.