Geology topics

Thomas C. Michot

Publications and source records attributed to Thomas C. Michot.

20 records · Page 2Linked to original sources

USGS1994

Winter biomass and nutrient values of three seagrass species as potential foods for redheads (Aythya americana eyton) in Chandeleur Sound, Louisiana

We studied biomass and macronutrient content of Halodule wrightii (shoalgrass) throughout the winter and of Thalassia testudinum (turtlegrass) and Syringodium filiforme (manateegrass) in January in Chandeleur Sound, Louisiana Halodule , the primary fcod of wintering redheads, had the lowest biomass of the three species on the study area in mid-winter. Macronutrient content of Halodule did not change during the winter, but aboveground and belowground biomass showed a 90 and 49% ( P <0.0001) decrease from October to March. Macronutrient content seems not to be the basis for selection by redheads of Halodule over the other two seagrass species or of selection of belowground over aboveground parts.

Louisiana↗

USGS1993

Diet differences in Redheads from nearshore and offshore zones in Louisiana

Habitat management decisions for diving ducks in winter are limited by the lack of information concerning their use of nearshore and offshore zones. Therefore, we compared diets of redheads ( Aythya americana ) collected from nearshore (n = 206) and offshore (n = 72) zones during winters at the Chandeleur Islands, Louisiana, 1987-89. A greater (P < 0.05) proportion of redheads from nearshore had food in their esophagus and proventriculus than redheads from offshore. Feeding redheads in the offshore zone consumed more (P < 0.05) animal matter (42% in esophagus) and less plant material (58%) than conspecifics feeding nearshore (13% animal, 87% plant). Contents of proventriculi showed the same trend (P < 0.05). Zone-related diet differences occurred in both sexes and in early and late winter. Food availability and nutritional needs may affect these differences.

Louisiana↗