Fat content in migratory central Arizona Brazilian free-tailed bats, Tadarida brasiliensis (Molossidae)

Southwestern Naturalist
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Abstract

Fat content of migratory Tadarida brasiliensis was determined during the spring, summer and fall of 1972 in the Verde Valley of Arizona. Fat indices were highest in March arrivals, generally declined throughout the summer, and were lowest in September. In both 1972 and 1973 bats had arrived at the study area by mid-March. In 1971 bats were last noted at the area in mid-October while in 1972 they had disappeared by late September. On the basis on physiological calculations it is estimated that bats collected in March 1972 possessed sufficient fat reserves to carry them a mean distance of 716 km north of the study area while September bats had only enough reserves to fly 386 km southward, about 160 km short of the nearest known Sonora wintering locality. It is suggested that in spring the bats may have a more rigidly timed migration and so put on excess fat to counter an uncertain environment to the north. The fall migration may be triggered by more unpredictable events, such as the passage of cold fronts, and less fat reserves may be required for movements into more favorable southern locales.

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Publication type Article
Publication Subtype Journal Article
Title Fat content in migratory central Arizona Brazilian free-tailed bats, Tadarida brasiliensis (Molossidae)
Series title Southwestern Naturalist
DOI 10.2307/3669717
Volume 21
Issue 3
Year Published 1976
Language English
Publisher Southwestern Association of Naturalists
Publisher location Dallas, TX
Description 6 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Southwestern Naturalist
First page 321
Last page 326
Country United States
State Arizona
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