Dissertations and Theses @ UNI

Availability

Open Access Thesis

Keywords

Hawks--Physiology; Fat cells; Fat cells; Hawks--Migration; Academic theses;

Abstract

Many species of birds store fat as the primary fuel for migration. Although this is well-documented in many avian families, little is known about fat-storing patterns of migrating birds of prey. Pre-migratory fattening has been recorded in falcons and presumed in buteos. However, fat-storing patterns in migrating Accipiter hawks has not been documented. This study examined the fat-storing patterns of Sharp-shinned Hawks (A. striatus) during a portion of its fall migration. During Sharp-shinned Hawk migration three possible fat-storing patterns are predicted: I) fat deposition increases, 2) fat deposition is maintained, or 3) fat deposition decreases. To determine which strategy is utilized, birds were trapped during September 1996 at two locations along their southward migration: Duluth, MN and Glen Haven, WI. These locations are approximately 460 km apart. Morphometric measurements were taken at each site to determine whether the birds represented similar populations. Pectoral muscle development was scored to determine condition. Subcutaneous subalar fat content was scored to determine fat deposition. Analysis of the morphometric data indicated the birds represented the same population. Fat and pectoral muscle score analyses suggested that Sharp-shinned Hawks store relatively little fat, while maintaining good muscle condition during early migration. The low fat storage was consistent with the optimal body fat hypothesis which predicted lower fat storage when food resources are predictable and with the increased threat of predation.

Year of Submission

1997

Degree Name

Master of Arts

Department

Department of Biology

First Advisor

Orlando Schwartz

Second Advisor

Jill Trainer

Third Advisor

Nixon Wilson

Comments

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Date Original

1997

Object Description

1 PDF file (36 leaves)

Language

en

File Format

application/pdf

Included in

Biology Commons

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