Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Brown-Headed Cowbirds in Eastern and Western North America Show Similar Use of Courtship Songs in Copulation Contexts

Edna Gorney-Labinger and Stephen I. Rothstein
The Condor
Vol. 104, No. 4 (Nov., 2002), pp. 866-872
Stable URL: http://www.jstor.org/stable/1370711
Page Count: 7
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Brown-Headed Cowbirds in Eastern and Western North America Show Similar Use of Courtship Songs in Copulation Contexts
Preview not available

Abstract

Past work with captive Brown-headed Cowbirds (Molothrus ater) has suggested geographic variation in the relative importance females place on the two categories of male courtship song, flight whistles and perched songs. However, audio-recorded copulation sequences showed that western M. a. obscurus (California) and eastern M. a. ater (Maryland, Oklahoma and Missouri) males gave both song categories immediately before and during most sequences in nature, matching previously reported data for the third subspecies, M. a. artemisiae. Thus field data provide no evidence for geographic variation in song use during mating. Because female lordosis responses to flight whistles in captivity can be negated by certain research methodologies, unlike perched song responses, flight whistle responsiveness appears to be more dependent on experience. In all regions, males sang at higher rates prior to and during copulation than in other contexts, a distinctive manner of vocalization that may influence female mating and fertilization choices. /// Estudios anteriores que utilizaron individuos de Molothrus ater en cautiverio han sugerido una variación geográfica en la importancia relativa que dan las hembras a las dos categorías de canto de cortejo de los machos: silbido al vuelo y canto de percheo. Sin embargo, grabaciones de audio secuencias de copulación mostraron que en estado silvestre los machos de M. a. obscurus del oeste (California) y M. a. ater del este (Maryland, Oklahoma y Missouri), presentaron las dos categorías de canto antes y durante la mayoría de las secuencias, lo que concuerda con datos previamente reportados para una tercera subespecie, M. a. artemisiae. Por lo tanto, los datos de campo no proveen evidencia de variación geográfica en el uso de los cantos durante el apareamiento. Debido a que la respuesta de lordosis de las hembras al silbido al vuelo se ve alterada por la variación en las metodologías de investigación usadas en cautiverio, mientras que la respuesta al canto de percheo no, la respuesta al silbido al vuelo parece ser más maleable. En todas las regiones, los machos cantaron a una mayor tasa antes y durante la cópula que en otros contextos, lo que representa un modo de vocalización distintivo que puede influenciar la elección de la pareja y fertilización de las hembras.

Page Thumbnails

  • Thumbnail: Page 
866
    866
  • Thumbnail: Page 
867
    867
  • Thumbnail: Page 
868
    868
  • Thumbnail: Page 
869
    869
  • Thumbnail: Page 
870
    870
  • Thumbnail: Page 
871
    871
  • Thumbnail: Page 
872
    872