Aechmophorus occidentalis—Western Grebe // Podiceps/Podilymbus—Eared/Pied-billed Grebe // Podiceps nigricollis—Eared Grebe // Podilymbus podiceps—Pied-billed Grebe // Tachybaptus dominicus—Least Grebe
Grebes are highly aquatic birds seldom leaving the water except in migration. They are expert divers and resort to diving both as a defensive mechanism and for food procurement. Four species regularly occur in our region at present (Ligon 1961).
Fig. 1. Horned Grebe (Podiceps auritus). Photograph by Donna Dewhurst courtesy of the USFWS.
Literature. Ligon 1961.
Grebes are obligate aquatic birds whose presence in fossil deposits implies presence of moderate to large bodies of water within a reasonable distance. Presence at Burnet Cave indicates a probable source in the Pecos Valley to the east, since it is unlikely that suitable habitat was present closer to the cave. Presumably the Colorado River supplied suitable habitat in the Grand Canyon region.
Fig. 1. Western Grebe. National Park Service photograph by Will Elder.
Mid/Late Wisconsin: Sandblast Cave (Emslie 1988)
Late Wisconsin/Holocene: Burnet Cave (Schultz and Howard 1935); Stanton's Cave (Rea and Hargrave 1984).
Literature. Emslie 1988; Rea and Hargrave
1984; Schultz and
Grebes are aquatic birds that are excellent swimmers and divers, requiring at least moderate-sized bodies of water. The diet consists of a wide variety of aquatic animals. The White Lake section of Pleistocene Lake San Agustín sedimentary deposits is the source of the fossil material; the lake itself should have been suitable habitat.
With presently available comparative material, the specimen, a femur, is identified only as a small grebe (Fig. 1).
Fig. 1. Right femur of a small grebe, Pleistocene San Agustín. Scale in mm.
Wisconsin: White Lake (Harris 1993c).
Literature. Harris 1993c.
Synonyms: Podiceps caspicus.
Occurrence at Dark Canyon Cave is not surprising since it is only a short distance from the Pecos Valley flood plain. The Pecos River or ox-bows of the Pecos should have been prime habitat.
Two bones represent this taxon from Dark Canyon Cave; Howard (1971) noted that they are slightly smaller than those of modern examples from New Mexico. She also noted that half of the Eared Grebe bones from Fossil Lake, Oregon, also were small.
Mid/Late Wisconsin: Dark Canyon Cave (Howard 1971).
Late Wisconsin/Holocene: Skylight Cave (Emslie 1988: cf. gen. et sp.); Stanton's Cave (Rea and Hargrave 1984).
Literature. Howard 1971; Emslie 1988; Rea and Hargrave 1984.
Fig. 1. Pied-billed Grebe; US Fish & Wildlife Service photo.
In common with many water birds, this grebe occurs throughout the region.
Mid/Late Wisconsin: Sandblast Cave (Emslie 1988).
Late Wisconsin: Skylight Cave (Emslie 1988).
Literature. Emslie 1988.
This, the smallest of the grebes, is considerably out of place compared to its current distribution. Its nearest approach now is on the western and eastern coasts of Mexico into extreme southern Texas. However, there are occasional occurrences in southernmost California and Arizona.
Sites. Medial Irvingtonian: San Antonio Cave (Rogers et al. 2000: cf.).
et al. 2000.
Last Update: 18 Mar 2013