Time and heat allocations to balance conflicting demands during intermittent incubation by Yellow-eyed Juncos

F. Reed Hainsworth, Thomas Moonan, Margaret A. Voss, Kimberly A. Sullivan, Wesley W. Weathers

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


We use a new method to analyze time allocations influencing average egg temperatures during intermittent incubation. It measures relative investment in parental self-maintenance versus embryo development rate, or the extent to which performance for either is compromised from integration of both functions. Unlike attentiveness (min/hour on the nest), we compare time when eggs cool and heat with the subsequent time when egg temperatures are kept relatively constant (t(equil)). When these times are equal eggs increase in mean temperature at a maximum rate/bout. Corresponding average egg temperatures are halfway between average egg temperatures achieved with high frequency incubation (t(equil) = 0) and those achieved with continuous incubation. We reanalyzed previously published data for Yellow-eyed Juncos Junco phaeonotus (Weathers and Sullivan 1989). Results showed variable rates of increase in mean egg temperatures, but over 4 of 8 days at 3 of 6 nests average egg temperatures represented a balance between the conflicting demands. Remaining days and nests showed allocations favoring embryo development rate. Thus females on average either balanced conflicting demands during incubation or were able to shift allocations toward development rate. This occurred because several bouts with short t(equil) favoring self-maintenance early and late in a day were balanced or exceeded by a few bouts with long t(equil) favoring development rate at midday.

Original languageEnglish (US)
Pages (from-to)113-120
Number of pages8
JournalJournal of Avian Biology
Issue number2
StatePublished - Jun 1998

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


Dive into the research topics of 'Time and heat allocations to balance conflicting demands during intermittent incubation by Yellow-eyed Juncos'. Together they form a unique fingerprint.

Cite this