Hatching and fledging times from grassland passerine nests

Studies in Avian Biology 43- 4
By: , and 
Edited by: Christine A. RibicFrank R. Thompson III, and Pamela J. Pietz



Accurate estimates of fledging age are needed in field studies to avoid inducing premature fledging or missing the fledging event. Both may lead to misinterpretation of nest fate. Correctly assessing nest fate and length of the nestling period can be critical for accurate calculation of nest survival rates. For researchers who mark nestlings, knowing the age at which their activities may cause young to leave nests prematurely could prevent introducing bias to their studies. We obtained estimates of fledging age using data from grassland bird nests monitored from hatching through fledging with video-surveillance systems in North Dakota and Minnesota during 1996&ndash;2001. We compared these values to those obtained from traditional nest visits and from available literature. Mean and modal fledging ages for video-monitored nests were generally similar to those for visited nests, although Clay-colored Sparrows (Spizella pallida) typically fledged 1 day earlier from visited nests. Average fledging ages from both video and nest visits occurred within ranges reported in the literature, but expanded by 1&ndash;2 days the upper age limit for Clay-colored Sparrows and the lower age limit for Bobolinks (Dolichonyx oryzivorus). Video showed that eggs hatched throughout the day whereas most young fledged in the morning (06:30&ndash;12:30 CDT). Length of the hatching period for a clutch was usually >1 day and was positively correlated with clutch size. Length of the fledging period for a brood was usually <1 day, and in nearly half the nests, fledging was completed within <2 hr. Video surveillance has proven to be a useful tool for providing new information and for corroborating published statements related to hatching and fledging chronology. Comparison of data collected from video and nest visits showed that carefully conducted nest visits generally can provide reliable data for deriving estimates of survival.

Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Hatching and fledging times from grassland passerine nests
Series title Studies in Avian Biology
Series number 43
Chapter 4
ISBN 9780520273139
Volume 43
Year Published 2012
Language English
Publisher University of California Press
Publisher location Berkeley, CA
Contributing office(s) Northern Prairie Wildlife Research Center
Description 14 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Video surveillance of nesting birds (Studies in Avian Biology no. 43)
First page 47
Last page 60