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Foraging Ecology Of Temperate-Zone And Tropical Woodpeckers, Robert A. Askins
Foraging Ecology Of Temperate-Zone And Tropical Woodpeckers, Robert A. Askins
Biology Faculty Publications
The foraging behavior of 11 species of woodpeckers in Guatemala, Maryland, and Minnesota was studied in order to test the seasonal stability hypothesis. This hypothesis predicts that specialization and species richness should be no greater for tropical wood-excavators than for those in the temperate zone because wood-excavators in both regions are buffered against seasonal change. Niche breadth values for six variables that describe foraging methods and perches were calculated by two methods. Unweighted niche breadth values were similar for tropical and temperate woodpeckers for all variables except foraging techniques; in this case the temperate species are more specialized. With weighted …
The Distribution, Ecology And Growth Of The Chestnut Lamprey, Ichthyomyzon Castaneus, In The Clearwater River, Minnesota, Charles S. Holt, Paul A. Durkee
The Distribution, Ecology And Growth Of The Chestnut Lamprey, Ichthyomyzon Castaneus, In The Clearwater River, Minnesota, Charles S. Holt, Paul A. Durkee
Journal of the Minnesota Academy of Science
This study dealt primarily with the ammocoete stage of the chestnut lamprey, lchthyamyzan castaneus (Girard). The population estimate for ammocoetes in the 25.5 m2 section studied was 540 individuals. The lengths of 452 ammocoetes collected ranged from 42 to 164 mm. A total of 213 chestnut lampreys were retained for laboratory study. Twenty of these were adults with an average length of 136.8 mm (range= 125 mm to 191 mm). Six age classes of ammocoetes were determined. An average increase in body length of recaptured ammocoetes of 2.9 mm was observed during the summers of 1980 and 1981. The habitat …