Degree Name

Master of Science (MS)

Semester of Degree Completion

1975

Thesis Director

Lawrence Barrie Hunt

Abstract

A series of homing experiments using 39 color-marked Bank Swallows (Riparia riparia) were carried out in eastern Illinois during the summer of 1975. The swallow colony was located four km east-northeast of Charleston, Illinois at the Charleston Stone Quarry. Eight release sites were located in the four compass directions from the home colony at distances of 14.4 to 32.3 km away.

The colony was approached before dawn and swallows were captured using tube traps. Birds were color-marked, banded, and taken in individual bags to the release site by automobile. Cloud cover, wind velocity, wind direction, and orientation behavior were recorded for each release.

Only 1/3 of the released birds successfully homed. Of the 13 that returned, eight homed from approximately 16 km north of the home site. There was a non-random final orientation between the north and northeast compass points (chi-square = 68.6; p<1%). Approximately 59% of these birds flying north-northeast homed successfully. The fastest homing velocity was 7.2 km/hr. There seemed to be no correlation between weather conditions and homing success. Swallows homed successfully under both clear and cloudy skies, and some succeeded against strong winds.

Returning swallows would typically approach the burrow several times, "hesitate" at the entrance, and finally enter the burrow. Almost immediately the swallow began to carry food or nesting material.

Some evidence exists that landmark and compass orientation were used by the swallows which homed. Evidence that landmark orientation was used is supported by the fact that sites #1 and #5 both produced more successful returns than any other sites. This type of homing improvement is said to be typical of landmark orientation. Approximately 56% of the swallows released chose a north-northeast orientation which tends to support compass orientation. However, this orientation could · have been a "nonsense" one since this orientation was not the home direction for any of the birds which flew in that direction.

Marking techniques were found to be inadequate because of poor visibility and low variability; therefore, homing success may have been better than the figures indicate. Possible solutions, although untested, include the use of colored streamers attached to the leg of the swallow or colored feathers glued to wing and tail coverts.

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