CLUTCH SIZE IN CAROLINA CHICKADEES.
CLUTCH SIZE IN CAROLINA CHICKADEES. T. David Pitts, The University
of Tennessee, Martin, Martin, Tennessee. Carolina Chickadees (Poecile
carolinensis) are small (body mass of approximately 10 g),
cavity-nesting birds that are permanent residents in Tennessee
woodlands, Each female chickadee typically lays only one clutch of eggs
per year. In northwestern Tennessee where I have studied Carolina
Chickadees since 1970, the earliest clutches are initiated in March and
the latest clutches are laid in May; the peak of egg laying typically
occurs in late March and early April. Clutches in Tennessee range in
size from 2-8 eggs. Both mean clutch size and maximum clutch size
increase from south to north across the range of Carolina Chickadees,
which includes 20+ states in the southeastern part of the United States.
Within each nesting season, clutch size and laying date are inversely
related. Unlike some other species of parids, nest cavity size has not
been shown to significantly affect clutch size in Carolina Chickad ees.
Approximately 60% of the females that nested in more than one year laid
clutches of the same size each year. All of the clutches of 8, the
largest clutches observed, were laid during 1978-1983, the six-year
period with the coldest winters that occurred during my study.