Colorado College Logo

  DigitalCC

Use AND (in capitals) to search multiple keywords.
Example: harmonica AND cobos

Brood size dependent differences in prey delivery rates among Flammulated Owls (Psiloscops flammeolus)

by Grundy, Bryan David

Abstract

Optimal clutch size has been an important focus within evolutionary biology since David Lack’s innovative work in 1947. Prey abundance, typically thought to limit clutch size, may be especially limiting in raptors, since the females contribute minimally to prey provisioning. Studying species with significant energetic constraints may illuminate the relationship between energetics, parental division of labor and clutch size. Flammulated Owls (Psiloscops flammeolus) are a small raptor with prey that is small relative to their body size, further constraining flammulated owls energetically when compared to raptors with larger prey. I hypothesized that female flammulated owls with clutches of three will contribute more to prey deliveries than females with clutches of two, while male prey delivery rates will not vary with brood size. Prey delivery data from 115 flammulated owl nests in the Front Range of Colorado were recorded from 2004-2013. During the second half of the nestling period broods of three received more prey deliveries than broods of two (p < 0.05). Additionally, during the second half of the nestling period no significant difference was found between male and female prey delivery rates for broods of three (p > 0.05). However, among adults with broods of two, males provided significantly more prey than females (p < 0.05). Male prey delivery rate between brood sizes was not significantly different (p > 0.05). These results indicate that broods of three may require greater energy expenditure than broods of two from the female, but not the male parent. While these results pertain to a bird with a small inflexible clutch size, similar research on birds with larger more flexible clutch sizes may reveal how and if clutch size and parental division of labor have co-evolved within avian taxa.

Note

PDF title page date: 19th day of May, 2014.

The author has given permission for this work to be deposited in the Digital Archive of Colorado College.

Includes bibliographical references.

Colorado College Honor Code upheld.

Administrative Notes

PDF title page date: 19th day of May, 2014.

The author has given permission for this work to be deposited in the Digital Archive of Colorado College.

Colorado College Honor Code upheld.

Copyright
Copyright restrictions apply.
Publisher
Colorado College
PID
coccc:9689
Digital Origin
born digital
Extent
34 pages : illustrations
Thesis
Senior Thesis -- Colorado College
Thesis Advisor
Snyder, Marc Linkhart, Brian
Department/Program
Biology
Degree Name
bachelor
Degree Type
B.A.
Degree Grantor
Colorado College
Date Issued
2014-05