Relative Organ Size in Migratory Birds

Kelsea Zitt Butler University, Lauren Goertzen Butler University
Faculty Sponsor(s): Shelley Etnier Butler University
Birds may travel thousands of miles during seasonal migrations. Before and during migration, researchers have observed physiological changes in the size of multiple organs. For example, before taking off, the heart and pectoral muscles of migratory birds undergo hypertrophy to cope with the exhausting flight (Starck, 1999; Piersma and Lindstrom, 1997; Piersma,1999). Conversely, the stomach, liver, and kidneys gradually decrease in mass before departure, while the intestines decrease in length (Piersma, 1998). Notably, the gizzard does not experience changes before or after migration nor does it atrophy like the liver and intestines during migration (Piersma, 1998; Starck, 1999). In this study, we investigate the relative size of organs in two small, migratory birds: Swainson's Thrush (Catharus ustulatus) and Tennessee Warbler (Leiothlypis peregrina). Samples were collected as part of the Butler Explores Avian Kollisions project (BEAK) which monitors window strike collisions on Butler's campus during the fall and spring migrations. Those specimens were used to establish standard values for the relative size in the pectoral muscles, heart, liver, kidney, gizzard and intestines in both species for each migration season. Gizzard contents were examined for changes between species and between spring and fall migrations. We will be testing hypotheses that organ-body size ratios are similar in the fall and spring, as well as across species.
Oral Presentation

When & Where

11:15 AM
Gallahue Hall 102