A Migratory Divide in the Painted Bunting (Passerina ciris)

Area of Science:

• Ornithology
• Population Genetics
• Evolutionary Biology

Background:

• Painted buntings (Passerina ciris) exhibit allopatric breeding populations along the Atlantic coast and interior southern US.
• Connectivity between breeding and wintering ranges for these populations remains poorly understood.

Purpose of the Study:

• To investigate the population structure and connectivity of painted buntings throughout their annual cycle.
• To identify distinct wintering ranges and migratory patterns using genomic and morphological data.

Main Methods:

• Analysis of genomic data from museum specimens and banded birds.
• Morphological measurements (wing length) correlated with genetic ancestry.
• Assessment of molt-migration phenologies.

Main Results:

• Identification of three genetically differentiated painted bunting populations.
• Confirmation of a distinct Atlantic coast population that remains allopatric year-round.
• Discovery of a migratory divide within the interior breeding range, with Louisiana populations wintering in the Yucatán Peninsula, distinct from those wintering in mainland Mexico and Central America.
• Association between genetic ancestry and wing length variation in interior populations.

Conclusions:

• Painted buntings comprise at least three distinct populations with unique migratory strategies and wintering grounds.
• The study reveals a previously unrecognized migratory divide within the interior breeding range.
• Selection may be driving morphological divergence linked to different migration strategies in painted buntings.